Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition associated with several negative health outcomes. A hallmark of ME/CFS is decreased exercise capacity and often profound exercise intolerance. The causes of ME/CSF and its related symptoms are unknown, but there are indications of a dysregulated metabolism with impaired glycolytic vs oxidative energy balance. In line with this, we recently demonstrated abnormal lactate accumulation among ME/CFS patients compared with healthy controls after exercise testing. Here we examined if cardiac dimensions and function were altered in ME/CFS, as this could lead to increased lactate production. Methods: We studied 16 female ME/CFS patients and 10 healthy controls with supine transthoracic echocardiography, and we assessed cardiac dimensions and function by conventional echocardiographic and Doppler analysis as well as novel tissue Doppler and strain variables. Results: A detailed analyses of key variables of cardiac dimensions and cardiac function revealed no significant differences between the two study groups. Conclusion: In this cohort of well-described ME/CFS patients, we found no significant differences in echocardiographic variables characterizing cardiac dimensions and function compared with healthy controls. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by fatigue, post-exertional malaise, pain, sleeping disturbances and exercise intolerance. Although its cause remains unknown, recent data point to dysregulated energy metabolism as a possible contributing factor ,2. In liStudies with magnetic resonance imaging (MRI) of the heart have suggested lower left ventricular dimensions and provided a plausible basis for reduced left ventricular function and exercise intolerance in ME/CSF . In suppApproval was obtained from the Regional Committee for Medical and Health Research Ethics in Norway (no. 2012/571-1), and the original study  is regisWe performed supine transthoracic echocardiography  after an overnight fast. Conventional echocardiographic, Doppler data and strain variables were analyzed offline by a trained specialist (TGvL) unaware of group affiliation, in accordance with established guidelines  and usinp-values using the Holm–Bonferroni sequential correction method [p < 0.05.All datasets showed a normal distribution as evidenced by Q–Q plots and Shapiro–Wilk’s test. Thus, we used Student’s t test to examine differences between the two study groups. Due to multiple comparisons between the two study groups, there was a possibility of familywise error rate (and thus Type I errors). We therefore adjusted the n method . This isp = 0.13), respectively, and the corresponding BMIs were 24.9 (18.6–31.3) and 23.7 (18.8–35.6) kg/m2, respectively (p = 0.54). On the day of the examination, cardiorespiratory symptoms were not reported by any of the participants in either of the two study groups.The mean (range) ages of the ME/CFS patients and the healthy controls were 40.1 (23.9–52.0) and 35.5 (25.0–44.3) years (p > 0.05) either. In line with these findings, no significant differences in systolic or diastolic blood pressure or in estimated systolic pulmonary artery pressure were found (data not shown). We next performed a wide range of assessments characterizing cardiac function in detail, both in diastole and systole. In addition to standard analysis of biplane left ventricular volumes and ejection fraction (ad modum Simpson), novel speckle-tracking echocardiography was performed. Global longitudinal left ventricular strain revealed similar results (p > 0.05) between the two study groups. Right ventricular function evidenced by tricuspid annulus plane systolic excursion (TAPSE) and peak systolic tissue Doppler velocity (not shown) was also comparable.Cardiac dimensions and function determined by echocardiography are summarized in p > 0.05). In summary, we could not find any significant differences in any parameters of cardiac function between the ME/CFS patients and the healthy controls.Impaired diastolic function is an established contributor to impaired exertional capacity. Here, early and late diastolic filling capacities were similar, as well as was early relaxation by tissue Doppler imaging and computed left ventricular filling pressures  (In this study, we were not able to detect any significant differences between ME/CFS patients and healthy controls in a wide range of variables characterizing cardiac dimensions and function with the use of conventional and advanced echocardiography. These findings, therefore, do not support the hypothesis that reduced cardiac dimensions or function may contribute to early exertional lactate accumulation, early gas exchange threshold or the low exercise capacity in ME/CFS that we recently reported . Our finEvidence for a reduced cardiac capacity in ME/CFS may not be evident in the resting state due to compensatory mechanisms, and absence of statistical differences in key echocardiographic parameters at rest do not necessarily mean that cardiac exertional capacities are similar. Moreover, in our previous study, we found similar blood concentrations of lactate among ME/CFS patients and controls at rest before the first exercise test, but during exercise the lactate concentration accumulated faster among the ME/CFS patients . It woulLimitations of our study were the small sample size and that we only included female ME/CFS patients with moderate disease severity. Strengths include well-characterized participants, including a matched control group, and use of detailed, state-of-the-art echocardiography.We found no significant differences in a wide range of conventional and novel echoardiographic variables characterizing cardiac dimensions and function when comparing ME/CFS patients with healthy controls. Further studies performed with exercising individuals, as well as directly linking cardiac function to biomarkers of metabolism, would be of interest.


Although nonsustained ventricular tachycardia (NSVT) is a risk factor for sudden cardiac death in hypertrophic‐cardiomyopathy (HCM), the impact of premature ventricular contraction (PVC) burden, in the absence of NSVT, is not well‐known.PVC burden may be associated with myocardial fibrosis and genetic mutations in patients with HCM.Of the 212 patients prospectively enrolled to the HCM registry of genetics, 84 were evaluated with both cardiac magnetic resonance, 24‐hour Holter monitoring and genetic analysis. Among them, 71 patients have not been diagnosed with NSVT.P = .003) and PVC burden  during 24‐hour Holter monitoring compared with others. The %LGE and global ECV were correlated with PVC burden . The optimal cutoff value for PVC number for LGE was 45  with 0.733 of the area under the receiver operating characteristic‐curve (P < .001). Thick filament gene mutation was more prevalent in the higher PVC burden group .Patients with NSVT (n = 13) had a higher late gadolinium enhancement (LGE) amount, extracellular volume fraction (ECV), and prevalence of sarcomere mutations compared with patients without NSVT. Among patients without NSVT, those with LGE (n = 46) had a higher total PVC (109 ± 332 vs 7 ± 13, Total PVC burden is significantly related to increase in myocardial fibrosis in HCM patients without NSVT. After excluding those patients who discontinued follow‐ups, were unable to visit the clinic due to migration or death, or were denied participation in the study, 212 patients were consecutively enrolled and underwent genetic testing. Of the 212 patients prospectively enrolled to the HCM registry of genetics,2.2A 24‐hour Holter monitoring was performed with SEER light  machine and was analyzed by both manual and automatic reviews of all 24‐hour echocardiography (ECGs). NSVT was defined as an episode of ventricular tachycardia (VT) with a heart rate of at least 120 beats per minute, lasting for at least three beats and persisting less than 30 seconds. Total PVC number was calculated, and two PVCs in a row were defined as couplet. PVC burden was defined as percent of total PVC number divided by total beats during monitoring.2.3. It was measured at resting and during Valsalva maneuver. LVOT obstruction was defined as a systolic pressure gradient ≥30 mmHg. Details are described in Supplementary Method S1.A routine standard echocardiography study was performed to measure the systolic and diastolic parameters according to the current American Society of Echocardiography guidelines.2.4Cardiac magnetic resonance (CMR) imaging was performed using a 1.5‐T scanner  with a phased array body coil. We analyzed LGE, T1, and extracellular volume fraction (ECV) for presenting myocardial fibrosis. The presence of LGE involvement in each segment and the total number of LGE‐involving segments was measured. Native T1 mapping with the modified Look‐Locker technique was performed during the mid‐diastolic phase, and post‐T1 mapping was performed 15 minutes after contrast media injection using the same slice axis and parameters as the pre‐T1 mapping. The percentage of LGE in LV mass was measured using dedicated quantitative analysis software  on LGE images with phase‐sensitive inversion recovery (PSIR). To improve the reproducibility, a radiologist and a cardiologist, both with more than 10 years of experience analyzed the LGE sizes. Boundaries of contrast‐enhanced areas were automatically traced in each short‐axis slice image. On LGE‐CMR images, the myocardium with an abnormal enhancement was defined as an area of hyperenhancement of more than five standard deviations from the remote myocardium. Remote myocardium was defined as nonenhanced myocardium, which is the opposite of hyperenhanced myocardium. Maximal signal was determined by computer‐assisted window thresholding of the enhanced area. Obvious artifacts, such as those caused by motion, were excluded using a tool from the software package. Total LGE volume was calculated by summing the LGE volumes of all the slices.ECV =  16‐segment model. Currently LGE, reflecting replacement fibrosis, is the most widely proven prognostic marker of SCD in HCM, therefore we chose LGE as a targeted value to determine the cutoff value of PVC burden.2.52.5.1MYH7, MYBPC3, MYH6, and MYL3) and thin filament genes (other sarcomere genes except for thick filament genes). The details are described in Supplementary Method S2.A literature search of the PubMed database was performed for targeted gene selection for the comprehensive HCM‐specific panel. It included 82 genes .2.6t tests were used to compare the means of the continuous variables that were approximately normally distributed between the two groups. Normality was determined using the Shapiro‐Wilk test. Categorical variables were reported as counts (or percentages) and were compared using the χ2 tests. For the reproducibility test, paired sample t‐tests were performed and Pearson's correlation coefficients were calculated. Receiver operating characteristic (ROC) analysis was performed to identify the optimal cutoff values of burden of PVC for the presence of LGE. All clinical statistical analyses were performed using the SPSS version 25.0 statistical package . A two‐sided P‐value <.05 was considered to be statistically significant.Continuous variables with normal distributions are reported as the mean ± SD or 95% confidence interval. The Student 33.1P = .005) and variants of uncertain significance (VUS) of sarcomere‐associated gene . PVC couplet was more prevalent in the NSVT group compared with the no NSVT group . In the echocardiographic analysis, the NSVT group had higher maximal wall thickness , higher LV end‐systolic volume , and lower LV ejection fraction , e′ , a′ , and s′  compared with the no NSVT group. In the CMR analysis, the NSVT group had higher %LGE amount of LV , higher number of LGE segments , and higher LV mass index  compared with the no NSVT group.We compared the baseline characteristics between patients with NSVT n = 13) and without NSVT (n = 71) (Table 3 and wit3.2P = .011), thicker filament gene mutation , and higher total beats , PVC burden  during a 24‐hour Holter monitoring compared with patients without LGE. In the echocardiographic analysis, patients with LGE had a lower a′  compared with patients without LGE. In the CMR analysis, the NSVT group had a lower post‐T1  and higher ECV , LV mass , and LV mass index  compared with patients without LGE.We analyzed the characteristics of the patients without NSVT (n = 71). Baseline characteristics between these two groups according to the presence of LGE are compared in Supplemental Table 3.3P = .002) and PVC burden  of the 24‐hour Holter monitoring. Furthermore, E/e′ was correlated with %LGE . Moreover, ECV correlated with total PVC beats  and PVC burden . Post‐T1 tended to be correlated with PVC burden and total PVC beats . The optimal cutoff value for PVC number for the presence of LGE was 45  with 0.733 of the area under the ROC curve (P = .001)  although it was not statistically significant, and significantly higher prevalence of thick filament gene mutation  compared with the lower PVC burden group . In the CMR analysis, the higher PVC burden group had more prevalent presence of LGE  and higher %LGE amount of LV , number of LGE segments , post‐T1  and ECV  compared with the lower PVC burden group. PVC couplet was more prevalent in the higher PVC burden group compared with the lower PVC burden group   had a tendency of more prevalent pathogenic or likely pathogenic sarcomere‐associated gene mutation  funded by the Ministry of Education. (2014R1A1A2055872).None. The authors had full access to and take full responsibility for the integrity of the database. All authors have read and agreed to the manuscript as written.Appendix S1: Supporting InformationClick here for additional data file.


P < 0.0001). In the hemodialysis group, modest correlation was evident between myocardial ECV and left atrial volume index , while there was no correlation between myocardial ECV and other cardiac parameters including left ventricular mass index and severity of myocardial ischemia. Cardiac CT-based myocardial ECV may offer a potential imaging biomarker for myocardial fibrosis in HD patients.Extent of myocardial fibrosis in hemodialysis patients has been associated with poor prognosis. Myocardial extracellular volume (ECV) quantification using contrast enhanced cardiac computed tomography (CT) is a novel method to determine extent of myocardial fibrosis. Cardiac CT-based myocardial ECV in hemodialysis patients with those of propensity-matched non-hemodialysis control subjects were compared. Twenty hemodialysis patients  and 20 propensity-matched non-hemodialysis controls  who underwent comprehensive cardiac CT consisted of calcium scoring, coronary CT angiography, stress perfusion CT and delayed enhancement CT were evaluated. Myocardial ECV was significantly greater in the hemodialysis group than in the control group (33.8 ± 4.7% versus 26.6 ± 2.9%;  The leading cause of cardiovascular death among HD patients is sudden cardiac death, however, the exact underlying arrhythmic mechanisms remain elusive3. A postmortem study of HD patients without coronary artery disease (CAD) showed that 98.3% had myocardial fibrosis, and the pattern of fibrosis was diffuse4. A recent study demonstrated that diffuse myocardial interstitial fibrosis, not replacement fibrosis, is associated with dispersion of ventricular repolarization in patients with hypertrophic cardiomyopathy5, which suggests the importance of including an assessment of interstitial fibrosis in risk stratification for ventricular arrhythmias. Traditionally, identification of myocardial fibrosis was performed by endomyocardial biopsy. However, this procedure is invasive and may lead to severe complications, while also suffering from sampling errors and interobserver discrepancies in interpretation7.The risk of cardiovascular mortality is increased in chronic kidney disease and hemodialysis (HD) populations11 Myocardial ECV is increased by myocardial fibrosis in a wide range of cardiac diseases, including cardiac sarcoidosis, cardiac amyloidosis, ischemic cardiomyopathy, hypertrophy cardiomyopathy and dilated cardiomyopathy11. An excellent correlation between myocardial ECV assessed by CMR and interstitial fibrosis determined by quantitative histopathology has been confirmed in a number of studies12. However, in patients with HD, low risk gadolinium-contrast medium for nephrogenic systemic fibrosis should only be administered with the smallest possible dose if contrast study is considered necessary for clinical management13.Cardiac magnetic resonance (CMR) can determine the extracellular volume fraction (ECV) of left ventricular (LV) myocardium by measuring T1 relaxation times before and after administration of gadolinium contrast, and has become a noninvasive standard reference of myocardial fibrosisP < 0.001)14. Moreover, Bandula et al. demonstrated a significant correlation between CT-derived myocardial ECV and histologic fibrosis as a percentage 15. Cardiac CT could thus offer a suitable approach for assessing myocardial fibrosis and coronary stenosis in a single study. However, whether or not ECV quantification by cardiac CT allows assessment of increased myocardial fibrosis in HD patients has not been investigated.Recently, several studies have demonstrated the potential of contrast enhanced cardiac computed tomography (CT) to assess myocardial fibrosis with myocardial ECV. Nacif et al. showed a good correlation between myocardial ECV values determined by CMR and cardiac CT , left atrial volume index (LAVI), and severity of myocardial ischemia.At our institution, a comprehensive cardiac CT consisted of coronary CT angiography (CTA), stress dynamic CT perfusion (CTP) and ECV measurement is considered for patients between 45 and 85 years old who are clinically referred for coronary CT angiography with moderate to high pretest likelihood for obstructive coronary artery disease. Between October 2013 and November 2016, a total of 402 patients underwent the comprehensive cardiac CT study. Among them, we consecutively recruited a total of 22 HD patients for this study. Of these, we excluded 2 patients who had undergone maintenance HD for < 12 months. Propensity score matched  non-HD control subjects without any history of cardiovascular disease other than CAD were selected from the same cohort. The final study population comprised the 20 eligible HD patients and 20 propensity matched control subjects. This study was approved by the Clinical Research Ethics Review Committee of Mie University Hospital and performed in accordance with relevant guidelines and regulations. Written informed consent for study participation was obtained from all participants .16, but in brief, the protocol included unenhanced CT , stress dynamic CTP , coronary CTA and delayed-phase CT .Comprehensive cardiac CT examinations were performed using a second- or third-generation dual-source CT . A comprehensive cardiac CT protocol has been described in detail in elsewhere17. Dynamic data sets were acquired for 30 s via an electrocardiographically triggered axial scan mode, repeated at 2 alternating table positions. Tube voltage was set at 80 kV and 70 kV with the second- and third-generation dual-source CT, respectively, and tube current was determined using an automatic exposure control system with a quality reference of 350 mAs/rot at 120 kV for the second-generation and 300 mAs/rot at 80 kV for the third-generation scanner. A standard prospective CTA was performed 10 min after stress dynamic CTP with injection of contrast medium at 0.84 mL/kg over 12 s (26 mgI/kg/s). Tube voltage was 2 × 100 kV or 80 kV in the second-generation scanner and 2 × 80 kV or 70 kV in the third-generation scanner, and tube current was determined using the automatic exposure control system with a quality reference of 350 mAs/rot at 120 kV in the second-generation scanner and 300 mAs/rot at 120 kV in the third generation scanner. Gantry rotation time was 0.28 s in the second-generation scanner and 0.25 s in the third-generation scanner.Stress dynamic CTP was performed with adenosine triphosphate administration and injection of 40 mL (an iodine concentration of 370 mgI/mL) of iopamidol  at a flow rate of 5 mL/s18. Tube voltage was 80 kV and tube current was 370 mA for the second-generation scanner, and was automatically determined by the automatic exposure control system with the quality reference of 580 mAs/rotation at 80 kV for the third-generation scanner. Pre-contrast CT was performed using the same acquisition protocol applied for delayed-phase CT. The time interval between stress dynamic CTP and delayed-phase CT was approximately 20 min.Seven minutes after coronary CTA, end-systolic delayed-phase images were acquired by electrocardiographically triggered axial scan at two alternating table positions20. Myocardial ECV was calculated using commercial software  employing the following equation: ECV = (ΔHUm/ΔHUb)·(1 − Hct), where ΔHUm is the change in myocardial CT attenuation, in Hounsfield units (HU), ΔHUb is the change in CT attenuation of the blood, and Hct is the hematocrit21  was obtained on the subtraction image 17. A normalized MBF value was calculated as an MBF value in each segment divided by the highest MBF value within the 16 segments on an MBF map, then SSS was calculated by adding scores of all segments using a 5-point scale based on normalized MBF values: 0 = normal (> 0.75); 1 = mildly abnormal ; 2 = moderately abnormal ; and 3 = severely abnormal (≤ 0.60).Stress dynamic CTP images were postprocessed using commercially available perfusion software . Myocardial blood flow (MBF) was estimated using a dedicated parametric deconvolution technique, based on a 2-compartment model of the intravascular and extravascular spaces24. Coronary CTA images were visually evaluated for the presence of stenosis in segments with a reference diameter ≥ 1.5 mm as the consensus decision of two observers. Severity of CAD was ranked using the Coronary Artery Disease Reporting and Data System (CAD-RADS): 0, no atherosclerotic change; 1, 1–24% stenosis; 2, 25–49%; 3, 50–69%; 4A, 70–99% in 1 to 2 vessels; 4B, 70–99% in 3 vessels or ≥ 50% in the left main coronary artery; or 5, 100%. Obstructive CAD was defined as stenosis ≥ 50% in ≥ 1 vessel (CAD-RADS ≥ 3)25.The amount of coronary artery calcium was quantified from unenhanced CT using the Agatston scoring method26. Echocardiography was performed in the supine position using a Vivid7 Dimension cardiovascular ultrasound system . LV mass was obtained from coronary CTA using commercially available software .LV volumes and LV ejection fraction (EF) were echocardiographically calculated using the modified Simpson method from apical 4- and 2-chamber views. LV systolic dysfunction was defined as an LVEF less than 50%27.Left atrial volume was measured from CT datasets  on a three-dimensional CT workstation  with the biplane area length methodU tests. Categorical data were assessed using the chi-square test or Fisher’s exact test, as appropriate. Correlations within each group between continuous indices were assessed using Pearson’s and Spearman’s correlation coefficients for parametric and nonparametric data, respectively. In a previous study22, ECV within each subject group was normally distributed with standard deviation of 5 percent points. Assuming a true difference of 5 percentage points between the population means of the HD and control groups, we will need to study 17 HD patients and 17 control subjects to be able to reject the null hypothesis that the population means of the HD and control groups are equal with the power of 0.80 and the Type I error probability of 0.05. Thus, the sample size of 20 per group in this study was considered sufficient for the purpose. Propensity scores for the likelihood of coronary artery disease  were obtained by logistic regression. Matching was made on logit-transformed propensity scores matched to the nearest neighbor in a 1:1 fashion with a caliper of 0.05. A blinded list of mixed HD patients and control subjects in a random order was used for CT image analysis. Two independent observers measured ECV to assess inter-observer reproducibility. Furthermore, one observer measured ECV twice with a washout period of 3 months to determine intra-observer reproducibility. The inter- and intra-observer reproducibility of the myocardial ECV measurement were tested by calculating mean bias and 95% limits of agreement  from Bland–Altman analyses, the coefficient of variation (CV), and interclass correlation coefficient (ICC). Values of P < 0.05 were considered significant. The analyses were performed using SPSS software .Normality was assessed using the Shapiro–Wilk test. Values are expressed as mean ± standard deviation, or median (interquartile range) as appropriate. Values were compared between the two groups by independent t tests and Mann–Whitney Demographic data for 20 HD patients and 20 propensity matched non-HD control subjects are shown in Table P = 0.009). However, there was no difference in severity of CAD as classified by CAD-RADS category, global MBF  or SSS . As for delayed-phase CT, 7 HD patients (22 of the 320 segments) and 8 control subjects (34 of the 320 segments) showed ischemic delayed enhancement, while none demonstrated non-ischemic delayed enhancement. All segments with ischemic delayed enhancement were excluded from ECV analysis.Table P < 0.0001) . Although none showed overt heart failure, LV systolic dysfunction was observed in 7 patients (35%) in the HD group and 1 patient in the control . However, even in a subgroup of patients without LV systolic dysfunction, myocardial ECV was significantly higher in 13 HD patients compared to 19 control subjects . The examples of myocardial ECV map are shown in Fig. 2) than in the control group . LAVI was significantly increased in the HD group than in the control group   than in the control group  and in the control  , while the mean intra-observer difference was 0.28 ± 1.37 (95% limits of agreement: − 2.97 to 2.41%). The CV for the inter-observer and intra-observer measurements of myocardial ECV was 3.20% and 2.98%, respectively. The ICC for the inter-observer and intra-observer measurements of myocardial ECV were 0.962  and 0.966 .In the current study, we investigated the extent of diffuse myocardial fibrosis by comparing myocardial ECV derived from cardiac CT between HD patients and control subjects for the first time. The main findings of our study were: (1) myocardial ECV was significantly greater in HD patients than in control subjects; (2) there was a significant correlation between myocardial ECV and LAVI in HD group.28. Compared to native T1 mapping by CMR, which potentially allows quantification of myocardial fibrosis in HD patients without use of contrast media30, ECV generally shows better agreement with histologic fibrosis. This is because native T1 is affected by more confounders  than ECV28. Additionally, myocardial ECV derived from cardiac CT had excellent inter- and intra-observer reproducibility in this study, which enhaced the validity and reliability of this study.By simply quantifying the interstitial presence of contrast medium relative to the plasma, ECV is well suited to measure interstitial expansion occurring with fibrosis in the absence of interstitial edema32. Analogous to these previous reports, the greater myocardial ECV of the HD group (33.8 ± 4.7%) in the present study would represent a development of myocardial fibrosis, whereas ECV of the controls (26.6 ± 2.9%) is within the normal range. Since it is well documented that ECV is elevated in patients with heart failure with reduced EF33 and there were more patients with LVEF < 50% in the HD group than in the control group, we performed a subgroup analysis that excluded patients with LVEF < 50% and confirmed that ECV was higher in the HD group. Of note, we found a significant correlation between myocardial ECV and LAVI in HD patients. Elevated ECV is reported to be a major contributor to the impaired LV relaxation and stiffness34. With increased LV stiffness, left atrial pressure rises to maintain adequate ventricular filling, and the increased atrial wall tension leads to subsequent left atrial enlargement. Our results showing the correlation between myocardial ECV and LAVI is consistent with this pathophysiological cascade and demonstrates the accuracy for the quantification of ECV in our study.Histological studies have shown that diffuse  myocardial fibrosis was found in HD patientsHowever, several factors potentially affecting myocardial ECV value should be considered when interpreting the results. First, the presence and extent of atherosclerosis in the coronary circulation may be related with increased myocardial ECV in HD patients. Indeed, HD patients exhibited higher calcium scores in the current study. However, we found no significant difference in the severity of obstructive CAD or the severity of myocardial ischemia between HD and control patients. While the effect of chronic myocardial ischemia appears limited in this study, a large-scale study is warranted to explore the effect of chronic myocardial ischemia.29. In our study, interdialysis body weight gain and ultrafiltration volume, representative of changing fluid status, showed no correlations with myocardial ECV. Dialysis vintage also did not show correlation with myocardial ECV. In this regard, a potential explanation is that myocardial fibrosis may correlate with duration of impaired renal dysfunction35. However, the accurate determination of the duration of renal dysfunction is generally difficult because determining the beginning of renal impairment is impossible.Second, whether fluid shifts affect myocardial ECV in HD patients remains an issue of concern since this is crucial to define the reliability of myocardial ECV as a potential marker of myocardial fibrosis among HD patients. However, a recent cardiac MR study by Graham-Brown et al. showed that changes in fluid status among HD patients did not affect native T1 signal, which is theoretically more sensitive to fluid status than myocardial ECV15. Moreover, the histological studies have demonstrated that HD patients showed a larger extent of diffuse myocardial fibrosis19. Third, although total radiation dose (11.3 ± 4.0 mSv) applied in this study was acceptable, combining ECV module and stress dynamic CTP with coronary CTA increased the doses of ionizing radiation and contrast agent compared with coronary CTA alone. Continuous effort to reduce radiation exposure and contrast agent is required. Forth, scan-rescan reproducibility, which is necessary to understand the potential usefulness of ECV in the serial assessment, was not evaluated in this study. Although a recent study showed a high repeatability of CT-derived ECV in patients with suspected coronary artery disease who underwent serial assessment of ECV with a median interval of 5.1 months36, future investigation of repeatability of ECV in HD patients is awaited. Finally, this study did not address clinical outcomes, further studies are warranted to reveal the relationship between myocardial ECV and future cardiac events.This study has some limitations that require acknowledgement. First, myocardial ECV data in our study were derived from a relatively small cohort from a single center. A large-scale study is warranted to validate the results of our study. Second, histologic validation was not performed. Subjects in this study were not eligible for endomyocardial biopsy. However, a previous study showed myocardial ECV determined by cardiac CT correlated with histologic quantification of myocardial fibrosisCardiac CT-based myocardial ECV offers a potential imaging biomarker for myocardial fibrosis in HD patients. Further work is warranted regarding the relationship between myocardial ECV and the development of arrhythmia and heart failure in HD patients.Supplementary Information.


In this follow-up cohort study, 75% of the patients who underwent LPA reimplantation survived until discharge. The survivors had subsequently well-developed pulmonary arteries and tracheas.Pulmonary artery sling (PA sling) often presents as a life-threatening condition requiring urgent surgical correction. We reported 32 cases of PA sling in children who were followed up postoperatively in the past 6 years. All patients with PA slings who were admitted to the hospital from January 2012 to December 2017 and underwent surgery were retrospectively analyzed. The mean age of the 32 patients at repair was 16.97 months . Six patients required ventilator assistance for respiratory failure. All children underwent left pulmonary artery (LPA) reimplantation (n = 32), and 3 patients needed reimplantation slide tracheoplasty (n = 3) due to ventilation weaning failure. Four patients died, 27 patients survived until discharge, and 18 patients were followed up. Pulmonary computed tomography imaging and echocardiography were performed in 18 patients who were followed up. After LPA reimplantation, the tracheal carina area was significantly enlarged compared to that preoperation ( It is characterized by a left pulmonary artery (LPA) from the right pulmonary artery (RPA) and flow between the trachea and esophagus to the left lung hilum; ~ 1/2–2/3 of PA sling patients were found to have complete tracheal rings, also known as "sling complexes"2. Patients with PA sling may experience early-onset dyspnea or difficulty swallowing due to abnormal LPA compression of the tracheobronchus and esophagus. However, many patients have “near-death” spells due to congenital bronchial abnormalities. To date, a few reports on PA sling have focused on the choice of surgical approach4, but there have been no reports of patient development, such as the development of the trachea, height and weight after surgery.Left pulmonary sling (PA sling) was first reported in 1897, and it is still a rare congenital cardiovascular abnormality8. The advantage of the method of correcting cardiovascular malformations and tracheal stenosis is that the problem can be solved with only one surgery. However, the obvious shortcomings of this method are below. First, the postoperative mortality rate of children under one year old is high9 for requiring longer cardiopulmonary bypass (CPB) times. Second, there are many early and late complications associated with tracheal anastomosis. Even the most popular slide tracheoplasty approach cannot avoid those complications such as anastomotic leakage, late tracheal softening and tracheal restenosis after tracheoplasty11. In recent years, some experts have adopted the strategy of single left pulmonary artery transplantation, thereby relieving pressure on the trachea, and obtaining space for the growth and development of the stenosed trachea. Kwak et al. performed left pulmonary artery transplantation alone in 14 PA sling children with tracheal stenosis12. However, the authors did not perform a long-term follow-up of tracheal development in these children. For PA sling children with tracheal stenosis, it is still unclear whether left pulmonary artery transplantation alone can promote further growth and development of the stenosed trachea. Cardiovascular computed tomography angiography (CCTA) is considered to contribute to the assessment of congenital heart disease (CHD)13, especially when planning for cardiovascular diseases and tracheobronchial abnormalities, so we performed pulmonary artery + 3D bronchial reconstruction evaluations for the followed-up patients.Current viable surgical options include LPA reimplantation and LPA reimplantation + tracheoplasty. Most researchers recommend correcting vascular malformations and tracheal stenosis at the same time under cardiopulmonary bypass through median sternotomyHere, we report our experience with 32 patients with PA sling who underwent left pulmonary artery reimplantation from 2012 to 2017. According to the preoperation and postoperation tracheal CT, the tracheal area was measured before and after surgery to assess tracheal development. In the end, a comparison of various developmental indicators among children of the same age was carried out.A total of 32 left pulmonary slings diagnosed by echocardiography and CT were retrospectively analyzed from January 2012 to December 2017 .Among the 18 follow-up patients, 9 were female, and 9 were male     in the change of tracheal carina area between the patients with only PAS (n = 12) and PAS + additional cardiac lesions (n = 6)  Fig. A. To red04) Fig. B. The no28) Fig. C. Moreov28) Fig. D. In addLong-term hypoxia and dyspnea caused by tracheal stenosis during early childhood can lead to limited development in PA sling children. We compared the patient's preoperative and current body height and weight. We mainly observed the body weight and height of normal children before and after surgery  Fig. . Thus, tThe mean follow-up time for 18 survivors was 25.23 months (age from 16.97 (0.5–128 months) to 43.22 (10–156 months). All patients  were asymptomatic at the last follow-up. The survival rate after simple left pulmonary artery reimplantation was 93.10%.15. Simultaneous LPA reimplantation and tracheoplasty are recommended under CPB in PA sling children with complete tracheal rings and tracheal stenosis17. Complete tracheal rings always prevent tracheal development. Tracheoplasty can treat tracheal stenosis directly and ensure ventilation postoperatively. Although the outcome of PA sling has improved in recent decades after the application of slide tracheoplasty, the complications of tracheoplasty still remain a great challenge and include anastomosis leakage, granulation tissue formation and tracheobronchomalacia20. If tracheobronchomalacia was found postoperatively, then these children had worse outcomes and needed more ventilation time11. If granulation of the tracheal tissue emerged postoperatively, then bronchoscopic intervention and a longer ICU stay would be needed17. Oshima et al. examined the postoperative complications11 of 31 children who underwent PA sling repair; 5 children developed granulation tissue, 3 children had tracheomalacia, and 2 children had anastomotic leakage. To avoid the complications of tracheoplasty, could complete tracheal rings continue grow only by removing PA sling compression? We have found that some PA sling children with complete tracheal rings who only underwent LPA reimplantation achieved good outcomes4, but these children need to be further followed up.PA sling is a rare, congenital cardiovascular disease in children and is always associated with tracheal stenosis and a complete tracheal ring21. In their study, 9 patients underwent LPA reimplantation only and survived until discharge. These 9 patients were followed up for 8 years (3.1–12.7 years) and were asymptomatic. However, there was no evidence to demonstrate that the stenosis site of the trachea can continue to grow with only LPA reimplantation.In our study, 32 pediatric LPA sling patients with complete tracheal rings and stenosis underwent LPA reimplantation only. A total of 3 children needed another slide tracheoplasty due to extubation failure. Among the other 29 children, 27 survived until discharge, 18 children were followed up, and 9 children were lost to follow-up for social reasons. The total in-hospital mortality rate in this study was 12.5%  in the tracheal carina area postoperatively without tracheoplasty. To reduce the effects of tracheal development rates at different ages, normalized values of tracheal carina area/height were applied and significantly increased after LPA reimplantation, which means that the tracheal carina area increased more rapidly than body height after LPA reimplantation. The normalized TA1/TA2 value also significantly increased from 0.6151 to 0.9665. The stenosis site of the trachea could grow faster than the normal site in PA sling children after LPA reimplantation. The normalized values of tracheal carina area/height and TA2/TA2 both significantly increased after LPA reimplantation in our study. In conclusion, the stenosis site of the trachea, even in PA sling children with complete tracheal rings, showed accelerated development after LPA reimplantation.It was believed that as long as complete tracheal rings were observed in PA sling children, tracheoplasty must be performed or tracheal developmental would stop. In contrast, in all 18 patients who were followed-up in our study, the tracheal stenosis site was observed to be growing after LPA reimplantation. The statistics show significant increases  in the flow velocity of the LPA before and after LPA reimplantation in our study. Although there was no significant difference, our result showed there was a downward trend in LPA blood flow velocity after surgery. This means that the further development of the diameter of LPA may have undergone after reimplantation.Left pulmonary artery stenosis after reimplantation is known to be a rare complication. In Goldstein and colleagues’ studyIt can be seen that all patients had a normal body height and weight postoperatively compared to the normal population of the same age. Some children even exceeded the development rate of the normal population postoperatively. Long-term hypoxia and dyspnea caused by tracheal stenosis during early childhood can lead to limited body development in PA sling children, and these factors can be significantly improved by accelerated tracheal development after LPA reimplantation. This may explain the accelerated development in body height and weight.Our experience with LPA reimplantation in 32 PA sling children with tracheal stenosis provides strong evidence in favor of the procedure. The follow-up of 18 children showed promising results regarding growth of the stenosis site in the trachea, even in patients with complete tracheal rings. We recommend that the choice of LPA reimplantation should be made carefully and by considering the patient’s clinical status. All the surgeries in this study were performed by the same surgeon; thus, we were able to eliminate the effects of interoperator variability on the outcome of surgery. This adds further value to our results. However, further investigations are be necessary to confirm which kinds of PA sling patients can truly benefit from LPA reimplantation.23.This study was approved by the Institutional Review Board . All the informed consents have been obtained from the patients’ parents due to all the patients under 18-year-old. All the methods were in accordance with the relevant guidelines and regulationsWe conducted a retrospective analysis of patients diagnosed with PA sling from 2012 to 2017 from our departmental database. Patients with LPA reimplantation were recruited for further study. The inclusion criteria were: ① pediatric patients under 18 years old; ② with a clear diagnosis of pulmonary sling and tracheal narrowing. The exclusion criteria were: ① the tracheal and pulmonary artery surgery at the first stage; ② patients with chromosomal abnormalities; ③ the patients received CPR during in the hospital. All methods required informed consent in accordance with the relevant guidelines and regulations. We recorded and summarized the clinical information, including sex, time of surgery, and weight at the time of surgery, symptoms, preoperative ventilation, surgical treatment, and prognosis, of patients with PA sling.1, when the diameter of the tracheal is less than 3 mm or the length of narrow section beyond 1/2 of the whole length of the tracheal, the patients needed to receive first stage surgery of both tracheal and pulmonary artery.The 4th intercostal space was incised and the chest was open. After the LPA freed, it was ligated with silk thread and the distal end of the LPA was blocked with blocking forceps. The LPA was cut 2 mm from the ligation line, and the broken end of the LPA was sutured. After the main pulmonary artery dissociated, the LPA and the main pulmonary artery was made an end-to-side anastomosis. If all the procedure completed, no bleeding was detected and the chest was closed. According to referenceDue to the 7-year study period, the patients underwent two different CCTA scans using a variety of different CT scanners. Echocardiographic images were reviewed by cardiologists, while CCTA images were reviewed in consensus by two radiologists in our group. CT image postprocessing used artificial image recognition based on custom software on MATLAB to determine the tracheal area at the narrowest section of the trachea.p value < 0.05 was considered to indicate a significant difference. Statistical analysis was performed using MATLAB software .Descriptive statistics are used to describe the frequency (percentage) of each anomaly. A paired t-test was used to compare the differences between the observations before and after surgery in patients with PA sling. A


R2 = 0.395–0.679, all p < 0.001) identified specific qualitative gait characteristics as independent determinants for all quantitative PA dimensions, whereas motor capacity was an independent determinant only for the PA dimension duration. Demographic and health-related parameters were not identified as independent determinants. High associations between innovative, qualitative, and established, quantitative PA performances may suggest gait quality as a potential target to increase quantity of PA in multi-morbid, older persons.This study aimed to identify determinants of quantitative dimensions of physical activity  in community-dwelling, multi-morbid, older persons with cognitive impairment (CI). In addition, qualitative and quantitative aspects of habitual PA have been described. Quantitative PA and qualitative gait characteristics while walking straight and while walking turns were documented by a validated, sensor-based activity monitor. Univariate and multiple linear regression analyses were performed to delineate associations of quantitative PA dimensions with qualitative characteristics of gait performance and further potential influencing factors . In 94 multi-morbid, older adults (82.3 ± 5.9 years) with CI , analyses of quantitative and qualitative PA documented highly inactive behavior (89.6% inactivity) and a high incidence of gait deficits, respectively. The multiple regression models (adjusted  Decreased motor capacity, defined as maximal level of functioning under standardized conditions , as wellAlthough there is still no gold standard in sensor-based activity monitoring , technicTurning while walking stands out as a more demanding movement for older persons, compared to straight walking ,24, and The potential of innovative, qualitative characteristics of PA performance have so far mainly been used in discriminative studies to describe motor differences between healthy, high functioning persons as compared to impaired populations ,19,30,36To represent specific disease-related symptoms, such qualitative measures are of particular interest for specific patient groups such as persons with CI. Especially older adults with CI have a reduced gait quality, which is not only a risk factor for falls but also a predictor for further cognitive decline ,40. HoweIn previous studies that aimed to identify determinants of PA performance, parameters of socio-demographic, medical, psychological, cognitive, or functional status were used and indicated low to moderate associations with quantitative parameters of habitual PA ,46,47,48To the best of our knowledge, a research approach to identify determinants of quantitative PA performance with focus on innovative, qualitative characteristics of gait performance in multi-morbid and older persons with motor and cognitive impairment has not been undertaken so far. Based on low levels of PA performance in older persons with CI , the devThe main aim of this study therefore was to identify potential determinants of established, quantitative parameters of habitual PA performance by using innovative, qualitative characteristics of gait performance, in addition to established variables such as demographic and health-related parameters and measures of motor capacity, in multi-morbid, older persons with mild-to-moderate CI. A further aim was to describe the innovative, qualitative, and established, quantitative variables of habitual PA performance. Based on results of previous research , we hypoThe present study is a cross-sectional observational study which used pre-intervention data from a randomized controlled trial (RCT) on effects of home-based training following inpatient rehabilitation . The RCTAge, gender, and number of medications were documented from patient charts at discharge from inpatient rehabilitation. Further outcome measures including fall-related self-efficacy , fall-rThe Short Physical Performance Battery , habituIn the participants’ home environment, habitual PA performance was measured for 48 h with the uSense activity monitor (attached to participants’ lower back using adhesive bands), a non-commercial activity monitor developed in a large EU-funded project , allowing ambulatory, long-term assessment of PA. The assessments of PA performance were considered valid if they included data on at least 48 h of activity measurement. Concurrent validity of the uSense have been proved under standardized conditions by simultaneous annotated video recording during scripted and unscripted activities of frail, older persons, showing an agreement of 95.1% and 92.8%, respectively . Good cot-tests and χ2-tests were used for the comparison of participant characteristics between persons with valid and invalid uSense measurements.Descriptive data are presented as means and standard deviations, medians and interquartile ranges (IQR), or numbers and percentages. Independent-samples Based on a scientific statement of the American Heart Association , charactThe independent variables were classified into following seven different domains, comprising established, quantitative motor, and non-motor parameters (domains 1–3), identified as potential determinants in previous comparable studies ,47,65,66p ≤ 0.05 to enter) were performed to identify independent determinants of the different quantitative dimensions of walking  as well as the total PA performance . Only the independent variables with the highest, significant regression coefficient within each of the seven different aforementioned domains of the univariate analyses were included in the respective multiple linear regression models.Subsequently, four multiple linear regression models  > 10 [Potential multicollinearity of independent variables (IF) > 10 ) and theIF) > 10 , and aut2R and influences of variables are given as unstandardized (Beta) and standardized (ß) regression coefficients. A two-sided p-value ≤ 0.05 indicated statistical significance. Data analyses were performed using SPSS Statistics 25 .The multiple regression models were described by the adjusted coefficient of determination n = 1), refusal to wear the activity monitor (n = 3), and premature removal of the uSense by participants (n = 12). No significant differences were found between characteristics of participants with valid versus invalid measurements (The study sample included 110 multi-morbid (number of medications: 9.6 ± 3.5), older (82.3 ± 5.9 years) persons, discharged from ward-based geriatric rehabilitation, with mild-to-moderate CI (MMSE score: 23.3 ± 2.4 points), advanced motor impairment (SPPB score: 5.2 ± 2.3 points), and moderate concerns about falling (FES-I short: 12.3 ± 4.3 points). Sixteen sensor-based assessments of PA performance were invalid due to technical failure , and the considerably higher number of walking episodes, compared to lying episodes per day  episodes, p < 0.001), are based on the mainly very short bouts of walking and longer bouts of lying. An average cadence of 74 ± 7 steps per minute and average step duration of 0.72 s  implied slow habitual walking, also typical for the frail study population. Further details on the description of the quantitative parameters of PA performance are shown in During the 48 h activity monitoring, the established, quantitative parameters revealed a predominantly sedentary behavior during the day (21.5 ± 1.2 h (89.6%) inactive vs. 2.5 ± 1.2 h (10.4%) active), distinctive for multi-morbid, older persons with CI. The significantly shorter duration of walking, compared to lying per day . More detailed outcomes of the univariate analyses are given in Non-motor variables including demographic variables (age and gender) and health-related variables ) showed moderate and mostly singular associations with the established, quantitative dimensions of PA performance. Only the FFABQ, documenting activity avoidance related to concerns about falling, was moderately associated with all of the quantitative dimensions of PA performance  as well as the intensity of total PA performance (Model 4), whereas the peak turning velocity was an independent determinant for the intensity of walking (Model 3). As either the mean or peak turning velocity showed the highest univariate associations with the established parameters of PA performance within the domain of qualitative gait parameters of turning while walking, the average turning duration and average turning angle were not included in the multiple regression models.2R = 0.395–0.679; all p < 0.001) given the limited number of determinants and the complexity of potential influences on PA behavior. No multicollinearity  or autocorrelation (Durbin–Watson: 1.633–2.027) were present in any of the multiple regression models, indicating the independence of included variables.The explained variance was relatively large in all models  ,62 and hThe harmonic ratios in the present study were considerably smaller than in previous studies (1.82–2.25) that have examined associations of step-to-step symmetry of habitual gait performance with falls or time to falls in on average seven years younger persons with and without CI ,77, agaiAlthough the mean turning duration in the present study was almost in line with findings from discriminative, observational studies in real-life settings in sixty-five-year-olds with Parkinson’s disease  or cogniIn addition, the absolute number of turns in the present study was about 350 turns per day lower as compared to an age-matched peer group without CI, better turning performance, and better walking capacity . The desWhile habitual PA performance has so far mainly been documented as established, quantitative dimensions in contexts of both scientific and public use, the qualitative characteristics of PA performance played a much lesser role due to methodological limitations for valid assessments in habitual settings. The potential determinants of quantitative PA performance were therefore restricted to established demographic and health-related variables, and parameters of motor capacity.Accordingly, the main objective of the present study was to identify determinants of PA performance by using innovative, qualitative measures of habitual PA as compared to demographic and health-related variables, and parameters of motor capacity in multi-morbid older persons with CI, in which detailed gait and activity analyses are methodologically challenging but urgently needed.To identify determinants of quantitative PA performance, a step-wise procedure was used. In a first step, variables from various domains were analyzed in univariate regression models.Demographic and health-related variablesAs hypothesized, the demographic and health-related variables showed only moderate and singular relationships with the quantitative dimensions of PA performance, documenting lesser associations of generic domains or assessments that have been developed for clinical documentation rather than the prediction of PA. Study results are in line with previous studies, showing low to moderate negative univariate associations of advanced age, female gender, or various health-related variables with habitual PA performances such as overall intensity or activity counts ,45. ThesMotor capacityThe significant associations of all motor capacity variables with all parameters of quantitative PA performance in the univariate analysis verified the hypothesis of a moderate to high association between motor capacity and quantity of PA performance in the study sample with impaired mobility. The study results confirm the moderate associations of various motor capacity measures  with quantitative variables of PA performance  in younger and fitter older adults ,80.Tests of motor capacity like the SPPB or TUG, as used in the present study, have been developed to investigate requirements and activities relevant to everyday life of older persons ,58. The Innovative, qualitative parameters of straight walkingIn 15 out of 32 univariate analyses, qualitative gait parameters of straight walking showed significant associations with quantitative parameters of PA performance. This result partially confirms our hypothesis of moderate to high associations between the quality and quantity of performance and suggests that a better quality of habitual gait implies better motor skills as important prerequisite for a higher quantity of PA. Interestingly, these associations were mainly documented for the duration or frequency of PA performance and less for the intensity measures. This finding may be due to higher energy costs per unit time of intensive activity and the reduced ability to provide this energy in old age ,82, indiOnly few studies investigated individual, qualitative variables of laboratory-based gait  as determinants of the quantity of PA performance in older adults ,79,83,84However, measures of qualitative capacity and qualitative performance may not be directly comparable . While qIn addition to laboratory-based studies on associations between qualitative capacity measures and quantitative performance measures, studies on associations of qualitative gait performance while walking straight and the quantity of PA performance could not be identified, with the consequence that a direct benchmarking to the present results was not feasible.Innovative, qualitative parameters of turning while walkingAll qualitative parameters of gait performance while walking turns were significantly and in most cases strongly associated with every quantitative dimension of PA performance in the present study. This result highlights the high proportion of turning during everyday indoor activities  and suggThe higher levels of PA performance in the present study were associated with lower turning duration as well as higher turning angle and velocity, which are usually prolonged or reduced, respectively, in older adults due to a loss of coordination as a compensation strategy to maintain balance ,69. AccoWhile findings on laboratory-based turning measures (180°turning of the TUG) in older adults showed only a moderate positive univariate association of turning velocity with the number of activity counts , the preAs studies on the relationship between qualitative measures of turning performance and quantitative measures of PA performance are lacking, benchmarking of the present findings with previous results was again not feasible.In a final step, directly competing variables, each with the highest significant coefficients from the univariate regressions of the different domains, were analyzed in multiple regression models to ascertain independent determinants of the quantitative dimensions of habitual PA.Demographic and health-related variablesNone of the demographic or health-related variables, included in the multiple regression models, remained as an independent determinant for the quantitative dimensions of PA performance. This result affirms the lesser suitability of demographic factors and health status for the determination of the quantity of PA, compared to motor variables, as already indicated by the results of the univariate analyses.Motor capacityAlthough the measures of motor capacity document key motor functions ,58 that Innovative, qualitative parameters of straight walkingThe present study identified independent associations between specific qualitative variables of gait performance while walking straight (AP step-to-step symmetry and AP and ML step regularity) and all quantitative dimensions of PA performance, suggesting that qualitative characteristics of habitual gait are relevant independent determinants for the quantity of habitual PA.The independent association of step-to-step symmetry with duration and frequency of walking may relate to typical deficits of older persons with CI, such as lower levels of PA performance  and a loIn contrast, step regularity may be more important in the context of the PA dimension intensity, as it is indicated by the positive independent association of ML step regularity with intensity of walking and the negative independent association of AP step regularity with intensity of total PA performance. These contrary associations may be due to different reasons. One could be a frequent change in the participants’ progression speed that results in a lower AP step regularity but indicates a better ability to quickly adapt/change walking speed, while simultaneously the ML step regularity increases and reflects a better ML stability. This assumption suggests that a better qualitative motor performance enables a higher intensity of PA, which confirms our hypothesis of a strong association between qualitative and quantitative PA performance. Another reason could be the age-related decline in step regularity that only occurs in AP direction , assuminInnovative, qualitative parameters of turning while walkingEither the mean or peak velocity of turning performance was the best independent determinant for all quantitative dimensions of PA performance in the present study, suggesting that qualitative parameters of habitual turning behavior represent superior determinants for the quantity of PA performance, compared to demographic and health-related variables, measures of motor capacity, and qualitative parameters of gait performance while walking straight.The present findings are coherent since turning while walking represents a more challenging movement for older persons as compared to straight walking ,24 that The present study is the first to use successfully validated methods  to documThe inconsistent usage of technical terms in the literature  and the large variety of partially not validated sensor technologies, assessment methods, and outcome characteristics, due to a rapid technical development in the field of motion analysis in recent years, are limiting the benchmarking of the present findings and the comparability between different studies.The present study results identified specific qualitative variables of gait performance, in particular while walking turns, as main determinants for the quantitative dimensions duration, frequency, and intensity of habitual PA (will we do if we can?) in multi-morbid, older persons with generally low gait quality and PA levels. Results indicate that the quality of motor performance may be superior to determine the quantity of motor performance as compared to established measures of motor capacity or demographic and health-related variables.As qualitative measures of habitual performance are associated with adverse events such as falls ,15,30, i


Background: Aortic valve sclerosis (AVSc), a common precursor to calcific aortic valve disease, may progress into advanced aortic stenosis with hemodynamic instability. However, plasma biomarkers of such a subclinical condition remain lacking. Since impaired fibrinolysis featuring dysregulated tissue plasminogen activator (t-PA) is involved in several cardiovascular diseases, we investigated whether endogenous t-PA was also associated with AVSc.Methods: Plasma t-PA levels were measured in 295 consecutive patients undergoing standard echocardiography and Doppler flow imaging. Multiple logistic regression analyses were used to assess the association between t-PA and AVSc. Receiver operating characteristic curve analysis was performed for determining the diagnostic value of t-PA for AVSc. The performance of adding t-PA to clinical signatures of AVSc was evaluated. Concentration of t-PA was assessed in human sclerotic and non-sclerotic aortic valves by histology and immunohistochemistry analysis.Results: Plasma t-PA was higher in patients with AVSc than in non-AVSc counterparts . C-statistics of plasma t-PA for discriminating AVSc was 0.698 (95%CI: 0.639–0.758). The performance of t-PA for identifying AVSc was better among male and non-hypertensive patients . Combination of t-PA and clinical factors improved classification of the patients . The concentration of t-PA was three times higher in sclerotic compared to non-sclerotic aortic valves.Conclusion: Elevated circulating t-PA level confers an increased risk for AVSc. Further prospective studies with larger sample size are needed to examine if t-PA could serve as a diagnostic clinical marker for AVSc. Calcific aortic valve disease (CAVD) represents the most prevalent valve disease worldwide , but it Although previous studies unveiled that CAVD shares certain pathophysiological similarities with atherosclerosis in terms of inflammation and dyslipidemia , 7, randOver the past decades, increasing researches have demonstrated an extensive cross-talk between inflammation and coagulation in stenotic valve lesions, which is attributed, at least partly, to calcification and mineralization of the aortic valve leaflets , 12. TheThe protocol was approved by the Shanghai Jiao Tong University ethic committee and conducted in accordance with the Declaration of Helsinki. All patients gave written informed consent.A total of 571 patients who underwent coronary angiography/intervention because of typical angina symptom and/or electrocardiographic ST-T wave changes from September 2017 to July 2018 were screened from the database of Shanghai Rui Jin Hospital PCI Outcome Program. Among them, 445 patients underwent standard two-dimensional echocardiography and Doppler flow imaging according to the recommendations of the American Society of Echocardiography . All mean = 21) or aortic stenosis (n = 13) as these conditions did not comply with the proper diagnosis of AVSc. We also excluded patients with acute coronary syndrome (n = 41), history of coronary artery bypass grafting (n = 16), renal failure requiring dialysis (n = 8), anticoagulation treatment (n = 17), blood system diseases (n = 2), pulmonary heart disease (n = 3), advanced heart failure  (n = 9) and cancer (n = 7), because these factors are likely to interfere t-PA measurement. Thus, the remaining 295 eligible patients were included in the cross-sectional study analysis, including 155 patients with and 140 patients without AVSc . Hy. Hy26). Fasting venous blood samples were taken from all participants within 24 h of echocardiographic examination. All blood samples were transferred at the freezing temperature and centrifuged within 30 min at 3,000 rpm for 15 min to obtain cell-free plasma. All samples were stored at −80°C before analysis. Plasma level of t-PA was measured using an ELISA kit (Tissue Plasminogen Activator (TPA) Human SimpleStep ELISA Kit; Abcam Cat No: ab190812) according to the product instructions.n = 2) or moderate aortic regurgitation with deteriorating renal function (n = 1). The non-sclerotic aortic valve tissues were obtained from three explanted hearts of cardiac transplant recipients.Human sclerotic aortic valve tissues were obtained from three patients with AVSc who underwent aortic valve replacement within 3 years because of aortic dissection . Sections were stained using hematoxylin and eosin (H&E), Alizarin Red S and Masson trichrome, respectively. For t-PA detection, sections were incubated with anti-t-PA antibody (1:50)  at 4°C for 12 h and then incubated with horseradish peroxidase (HRP)-conjugated secondary antibodies (1:100) (CST: #3900S) at room temperature for 2 h. Image of all sections were photographed through a microscope (Zeiss Microsystems).t-test (Student's t-test or Welch's t-test) or non-parametric test while categorical variables in two groups were compared by Chi-squared tests. Spearman rank correlation was conducted to evaluate the correlations between clinical parameters and t-PA concentrations. Due to its right skew, t-PA concentration was expressed as log 10 transformed per SD in logistic regression model analysis and divided into ordinal variable based on its tertile using the lowest tertile as reference for comparison. Univariate logistic regression models were performed to examine possible factors associated with AVSc. Multivariable logistic regression analysis was conducted to assess the independent association between t-PA and AVSc. In Model 1, demographic features were included as covariates. To detect whether the association between t-PA levels and AVSc could be affected by other confounders, we further adjusted age, gender, smoking, diabetes, coronary artery disease, hypertension, lipid profiles, C-reactive protein (CRP), gamma-glutamyltransferase (γGT), eGFR, and levels of phosphorus in Model 2. Odds ratios with 95% confidence intervals (CI) were reported. Receiver operating characteristic (ROC) curves were constructed to estimate the performance of t-PA concentration for discriminating AVSc in the whole study population and different subgroups. The optimal cut-off value of t-PA concentration was calculated based on the highest Youden index (sensitivity + specificity – 1). C-statistics with 95% CIs were reported. To distinguish the representative variables for AVSc, the least absolute shrinkage and selection operator (LASSO) approach was utilized for feature selection (Continuous variables are expressed as mean with standard deviation (SD) if data were normally distributed, then presented as median with interquartile ranges (IQRs). Categorical data are summarized as proportions and frequencies. Continuous variables between two groups were compared using election –31. The http://www.r-project.org; version 3.6.1), and two-sided p-value <0.05 was considered statistically significant.Data were analyzed with the use of SPSS 22.0., statistical packages R glmnet (version 3.0-2) . In addition, plasma levels of HDL-C, phosphorus and eGFR were lower but CRP and γGT were higher in patients with AVSc . However, the two groups did not differ with respect to gender distribution, percentage of diabetes, smokers, plasma level of triglyceride, total cholesterol, LDL-C, and fast blood glucose. No significant difference was observed in terms of left ventricular geometry and function between the two groups. Medications including statin and antiplatelet treatments were also similar ] , p < 0.001]. Such an association remained significant even after adjusting for either demographic features alone  or demographic features, clinical and laboratory cofounders . An independent association between the highest tertile of t-PA level and AVSc was also observed after full adjustment  (Plasma levels of t-PA were significantly higher in patients with AVSc [median = 2063.10 pg/mL (IQR 1403.54.89–2731.46 pg/mL)] than in non-AVSc counterparts [median = 1403.17 pg/mL ] .The Spea 0.001)] . In univ = 0025] .Furthermore, higher plasma levels of t-PA still tended to be associated with higher risks of AVSc in different subgroups after adjusting for other confounding factors. In particular, t-PA levels appeared to add more risk for AVSc in male patients, those with younger age, diabetes, or those without hypertension .To evaluate the discriminability of plasma t-PA levels for AVSc, we performed ROC analysis and calculated the C-statistics. In our whole study population, t-PA held a C-statistics of 0.698 (0.639–0.758), with a cut-off value of 1845.79 pg/ml . The performance of t-PA in discriminating AVSc in different subgroups is summarized in For detecting the potential role of t-PA in assisting clinical factors for AVSc classification, a LASSO logistic regression was initially performed for selecting the representative signatures of AVSc among all clinical and laboratory features. Remarkably, based on lambda with one standard error from the minimum, t-PA (lg/SD) was selected as one of the representative variables for AVSc, along with another four clinical variables, including age, presence of coronary artery disease, HDL-C as well as eGFR . These fHematoxylin-eosin (HE), Masson, and alizarin red staining revealed that aortic valve leaflets were thicker and more fibrotic or calcified in AVSc patients compared to non-AVSc counterparts . ImmunohThe results of this study showed that elevated t-PA levels in plasma were associated with higher risk of AVSc, and may hold potential in AVSc discrimination especially for male, non-hypertensive and normal renal function patients. The concentration of t-PA was increased in sclerotic aortic valves.Growing publications indicated that impaired fibrinolysis was associated with CAVD , 32. HowMoreover, beyond the relatively satisfactory discriminability in the whole study population, plasma t-PA tended to be an indicator of AVSc among patients without hypertension. Over the past years, accumulating evidence revealed that hypertension was more prevalent in patients with CAVD , 35, andIn this study, we applied the machine learning approach LASSO regression for feature selection, which shrinks some variables coefficients to zero to ruling out redundant or irrelevant features or features that are strongly correlated and generate easily interpretable models with concise information . Interesin vivo and in vitro  . Animal in vitro , 19. In in vitro , it is rAortic stenosis is the most common form of valvular heart disease in the elderly population and occurs frequently in conjunction with coronary artery disease . In thisAdmittedly, several limitations exist in our study. First, as a single-center study, patient recruitment, staff characteristics, and departmental protocols might add a limitation to the universality of our results. Secondly, our diagnosis of AVSc is based on transthoracic echocardiography, and AVSc has not been assessed quantitatively by cardiac computed tomography. Though cardiac CT has not been recommended by guidelines as a routine test, it has been shown to display the burden of calcium weight in the aortic valve area. Additionally, despite careful adjustment for the major known confounders, unspecified elements could also interfere with our findings. Finally, as observational cross-sectional study, the prognostic value and causal relationship cannot be concluded. Further basic researches and clinical investigation are still required.The current study indicates that elevated plasma t-PA confers an increased risk for AVSc. This observation could extend our understanding of the pathophysiology of CAVD. Further prospective studies with larger sample size are needed to examine if t-PA is able to serve as a diagnostic clinical marker for AVSc.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by Ruijin Hospital Ethics Committee, Shanghai Jiao Tong University School of Medicine. The patients/participants provided their written informed consent to participate in this study.All authors contributed to conception and design, acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, and gave final approval of the version to be published. Individual significant contributions include: YL and KY provided study design, interpretation, and edited manuscript, were the guarantors of this work and took full responsibility for the work. ZC, YS, and QX performed data collection and wrote the manuscript. XH, YZ, YY, and ZC analyzed the data. WS contributed to interpretation, drafting, and editing the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


At lower pacing rates, untreated TAC induced elevated LV epicardial APD60. Fitted APD60 steady state (APDss) was reduced in treated TAC hearts. At higher pacing rates, treatment heterogeneously reduced APD60, compared with untreated TAC hearts. Variance of conduction loss was reduced in treated hearts compared with untreated hearts during fast pacing. However, CV was markedly reduced in both treated and untreated TAC hearts throughout dynamic pacing. At 150 ms pacing cycle length, APD60 versus diastolic interval dispersion was reduced in treated hearts compared with untreated hearts. Chronic activation of cardiac cholinergic neurons improved electrophysiological adaptation to increases in pacing rate during the development of TAC-induced heart failure. This provides insight into the electrophysiological benefits of cholinergic stimulation as a treatment for patients with heart failure.Left ventricular (LV) electrical maladaptation to increased heart rate in failing myocardium contributes to morbidity and mortality. Recently, cardiac cholinergic neuron activation reduced loss of contractile function resulting from chronic transverse-ascending aortic constriction (TAC) in rats. We hypothesized that chronic activation of cardiac cholinergic neurons would also reduce TAC-induced derangement of cardiac electrical activity. We investigated electrophysiological rate adaptation in TAC rat hearts with and without daily chemogenetic activation of hypothalamic oxytocin neurons for downstream cardiac cholinergic neuron stimulation. Sprague–Dawley rat hearts were excised, perfused, and optically mapped under dynamic pacing after 16 wk of TAC with or without 12 wk of daily chemogenetic treatment. Action potential duration at 60% repolarization (APDNEW & NOTEWORTHY Analysis of electrophysiology from optical mapping of failing left ventricular myocardium provided insight into the possible therapeutic outcomes of cholinergic stimulation within the left ventricle. Chronic hypothalamic oxytocin neuron activation for downstream cardiac cholinergic neuron stimulation blunted onset of failing electrophysiology induced by pressure overload-induced heart failure in rats. Despite major medical advances, morbidity and mortality from cardiac arrhythmia remain high in patients with heart failure , 22, 35.We examined the hypothesis that during pressure overload-induced heart failure, epicardial depolarization and repolarization would fail to adapt to increases in heart rate. We studied a rat model of early-onset heart failure from transverse-ascending aortic constriction (TAC) by optically mapping left ventricular (LV) epicardial electrophysiology. Epicardial APD, CV, conduction failure, and APD versus DI dispersion were examined during dynamic pacing to assess electrophysiological responses to chronotropic stress. These parameters were significantly altered after 16 wk of TAC.As effective heart failure treatment remains elusive , increasMale Sprague-Dawley rats were bred and housed at the George Washington University’s Animal Research Facility. Rats were fed standard chow ad libitum with free access to water in single housing with a 12-h:12-h light-dark cycle. Rats underwent additional in vivo assessments for parallel research studies. All animal procedures were approved by the George Washington University’s Institutional Animal Care and Use Committee.TAC surgery was performed at 1 wk of age, as previously reported , 17. Bri3Dq DREADDs in a Cre-dependent manner. This combination allowed selective expression of DREADDs within PVN oxytocin neurons as previously reported (N-oxide (CNO) at 1 mg/kg body wt  began at 5 wk of age and continued until euthanasia at 16 wk of TAC. CNO is variably converted to clozapine, which passes the blood-brain barrier and binds to DREADDs , TAC (n = 5), and TAC + CNO (n = 7). Upon euthanasia, DREADDs expression within PVN oxytocin neurons was confirmed by microscopy of a coexpressed fluorescent tag. Most saline-injected rats had the DREADDs injection, and all were included in analysis even if labeling was not detected. However, CNO-injected rats were excluded if no labeling was detected, with exception of inconclusive negative labeling in one TAC + CNO rat.The following three groups were analyzed: Sham (2-5% CO2. Perfusate contained (in mM) 118 NaCl, 4.7 KCl, 1.25 CaCl2, 0.57 MgSO4, 1.17 KH2PO4, 25 NaHCO3, and 6 mM glucose. The heart was rotated for anterior LV epicardial optical mapping while partially submerged in recirculating perfusate. Electrocardiogram electrodes and a thermocouple monitored heart rate and bath temperature.At 16 wk of TAC, rats were placed in a deep surgical plane of anesthesia by isoflurane inhalation, confirmed by lack of pedal reflex, and extremely reduced breath rate. The heart was then quickly excised via thoracotomy and placed in cold media to slow heart rate and aid aortic cannulation. The heart was then Langendorff perfused at constant aortic pressure (75 mmHg) with 37°C perfusate oxygenated with 95% OAfter a brief period of equilibration, hearts were excitation-contraction uncoupled with a slow bolus injection of blebbistatin (Sigma-Aldrich) into aortic flow for a final circulating concentration of 7 μM. After contractile arrest, a bolus of the fast-response potentiometric fluorescent probe RH237 (Invitrogen) with 528 nm/782 nm excitation/emission was injected into aortic flow for a final concentration of 0.7 μM. RH237 was excited using two 530-nm light-emitting diodes (Mightex), each with an added 530–560 nm bandpass filter (Chroma). Excitation light intensity varied between several hearts due to photobleaching concerns. Shifts in RH237 emission peak due to changes in epicardial cardiomyocyte membrane potential were acquired with a high speed 128 × 128 pixel  EMCCD camera (Andor iXon DV860) with an added 680-nm long-pass filter (Chroma) A.Hearts were dynamically paced  during optical mapping using an electrode placed on the base of the LV epicardium A. The dyOptically mapped fluorescence was analyzed using in-house MATLAB software to measure the time of depolarization and repolarization at each pixel. A region of interest for analysis was drawn to include the LV, but to exclude the right ventricle (RV), atria, and curved edges of the LV. Residual motion artifact was removed through nonrigid registration of the raw fluorescence data, as described by Christoph and Luther . Saturat60) was measured to assess ion channel activity in the slower repolarization phase of the AP, an interval that has been shown to be altered during volume overload-induced heart failure in rats  of ATs  of ATs . Fits we60 and CV were then averaged at each pixel using the last four consecutive optical APs  of each PCL  versus DI per PCL for each heart. APD60 restitution vector angle was calculated from the positive horizontal (right hand) to the vector pointing from the 175 ms PCL restitution point to the 150 ms PCL restitution point. Similarly using per-pixel APD60 and DI mean values for per-pixel restitution points, a vector angle at each pixel was also computed and mapped to show dispersion of restitution vector angle.A PCL’s global mean was calculated using the APD60 = APDss·[1 − b·exp(−DI/τ)] (Eq. 1) using a nonlinear least squares approach in MATLAB. This provided further insight into differences in APD60 between the groups in a manner that incorporated the full APD60 restitution relationship. Due to the important association between steady-state APD and the APD restitution curve (60 restitution data were fitted to measure steady state at APD60 (APDss) for each heart. The parameters of Eq. 1  were first fitted using restitution data of all hearts in each group to provide one parameter set for each group. The distribution of APDss among hearts was then computed for each group by fitting the restitution data of each heart while setting b and τ equal to those of the group fits.Restitution data were fitted to the monoexponential function APDon curve , APD60 r60 mean versus per-pixel DI mean was analyzed for dispersion from the global mean restitution point and the predicted PCL = APD + DI line for each PCL .Planned contrast comparisons of Sham versus TAC and TAC versus TAC + CNO were performed after meeting equal variance (Brown–Forsythe) and normality assumptions. Comparisons were conducted using Fisher’s least significant difference test with a single pooled variance in Prism 8 (GraphPad), not correcting for multiple comparisons. A P = 0.0054). LV free wall and septum thickness in TAC hearts (P = 0.0007 and P = 0.0009) were significantly larger than Sham hearts.Compared with Sham, rat weight was significantly reduced after 16 wk of TAC (60 mean at 250 ms PCL compared with Sham hearts (P = 0.0108), but not when compared with TAC + CNO hearts (P = 0.1842). At 250 ms PCL, both TAC and TAC + CNO had heterogeneous long and short APD60 across the LV, as seen in per-pixel APD60 mean maps . However, APDss from fitted APD60 restitution curves was significantly higher for TAC than Sham (P = 0.0010) and TAC + CNO (P = 0.0220) (C and D). The transition from 175 ms to 150 ms PCL of the APD60 restitution curve was quantified by restitution vector angle (P = 0.0619) and TAC + CNO (P = 0.1176) hearts  , C and Dor angle E. Althou) hearts F. RegionP = 0.0010) than Sham hearts at 250 ms PCL, and TAC hearts demonstrated complex activation wave propagation compared with Sham hearts . Additionally, CV restitution values for TAC and TAC + CNO were consistently lower than that of Sham across PCLs (E and F). In TAC hearts, a reduction in PCL from 250 ms to 150 ms resulted in fewer per-pixel AP detections across 4 beats, which demonstrates increased conduction loss compared with Sham and TAC + CNO hearts (P = 0.0012)  D. Additi60 versus DI dispersion analysis . Distance versus angle plots showed how pixels fell into 10° segments centered at 135° and 315° along the predicted PCL = APD + DI line (P = 0.0029) and TAC + CNO (P = 0.0013) hearts .Each pixel’s repolarization rate response to a single PCL was quantified using APDanalysis C. At 150 DI line A. At 250 DI line C. Howeve) hearts D. In at 60 restitution curve, increased APD60 versus DI dispersion, slowed conduction, and increased variance of epicardial conduction loss during dynamic pacing. We sought to blunt such TAC-induced electrophysiological changes by stimulating myocardial cholinergic activity via chronic activation of PVN oxytocin neurons. Our results show that cholinergic stimulation blunted TAC-induced electrophysiological alterations by reducing APD60 versus DI dispersion and the variance of epicardial conduction loss during dynamic pacing. Additionally, cholinergic stimulation reduced APD60 elevation in large epicardial regions as well as reduced fitted APDss compared with TAC.In this study, we measured LV epicardial electrophysiological parameters after 16 wk of pressure overload-induced heart failure in rats. We found that TAC elevated the APD60 increase in TAC LV epicardial tissue compared with Sham  (+ current (IKr) (+ current density is suggested to be caused by increased α1 adrenergic activation (+ channel expression (+ current density combined with dysregulation of intracellular Ca2+ that occurs during heart failure (2+ ATPase (SERCA) activity (+/Ca2+ exchanger (NCX)  , 40, andnt (IKr) , 36. Acutivation  resultinpression , 25. Redactivity  and increr (NCX)  that bot2 muscarinic stimulation could blunt elevated β2 and α1 adrenergic signaling  differ from the PCL. This could be caused by local CV alterations that may occur in areas bordering conduction delays, where slight shifts in propagation direction would create localized variations in cycle lengths. APD responds to these local cycle lengths, establishing a new APD + DI relationship that is parallel and offset to the predicted PCL line. The location of the APD versus DI point along that new parallel line is dictated by the local tissue restitution properties. Increased incidence of offset from the predicted PCL line indicates decreased homogeneity of rate adaptation to the PCL, as we observed for TAC hearts. Additionally, a localized failure of 1:1 capture could drag a pixel off the predicted line and may explain how some pixels exceeded the maximum PCL window, as also observed for TAC hearts.When analyzing APDngle PCL . For exa60. However, the lack of a consistent and clear correlation in plots of per-pixel APD60 mean versus per-pixel steady-state fluorescence intensity and variance in Sham, TAC, and TAC + CNO hearts  suggests that artifactual APD60 did not dictate the outcomes of this study due to appropriate noise exclusion.Importantly, fewer pixels falling within 10° segments surrounding the PCL = APD + DI line marked increased maladaptive epicardium upon increased rate in TAC hearts compared with TAC + CNO hearts . Noise i60, and APD60 versus DI dispersion during sequential reductions in PCL were significantly altered after 16 wk of TAC compared with healthy Sham controls. Chronic chemogenetic activation of hypothalamic oxytocin neurons for downstream cardiac cholinergic neuron stimulation improved electrophysiological adaptation to increases in pacing rate during the development of TAC-induced heart failure. In addition to reducing APDss, activation of cardiac cholinergic neurons blunted APD60 elevation in large epicardial regions, reduced variable conduction loss, and reduced APD60 versus DI dispersion during rapid pacing. These results provide insight into the electrophysiological benefits of cholinergic stimulation as a potential treatment for patients with heart failure.LV epicardial conduction, APDThis work was supported by American Heart Association Predoctoral Fellowship 18PRE34030376 (to F. M. Zasadny), American Autonomic Society Postdoctoral Fellowship , and National Heart, Lung, and Blood Institute Grants R01 HL133862 and R01 HL146169 (to M. W. Kay. and D. Mendelowitz).No conflicts of interest, financial or otherwise, are declared by the authors.F.M.Z., J.D., D.M., and M.W.K. conceived and designed research; F.M.Z. and J.D. performed experiments; F.M.Z. analyzed data; F.M.Z. and M.W.K. interpreted results of experiments; F.M.Z. prepared figures; F.M.Z. drafted manuscript; F.M.Z., J.D., N.M.D., D.M., and M.W.K. edited and revised manuscript; F.M.Z., J.D., N.M.D., D.M., and M.W.K. approved final version of manuscript.