Activities of daily living, such as walking, are impaired in chronic low back pain (CLBP) patients compared to healthy individuals. Thereby, pain intensity, psychosocial factors, cognitive functioning and prefrontal cortex (PFC) activity during walking might be related to gait performance during single and dual task walking . However, to the best of our knowledge, these associations have not yet been explored in a large sample of CLBP patients.Gait kinematics  and PFC activity  during STW and DTW were measured in 108 CLBP patients . Additionally, pain intensity, kinesiophobia, pain coping strategies, depression and executive functioning were quantified and correlation coefficients were calculated to determine the associations between parameters.The gait parameters showed small correlations with acute pain intensity, pain coping strategies and depression. Stride length and velocity during STW and DTW were (slightly to moderately) positively correlated with executive function test performance. Specific small to moderate correlations were found between the gait parameters and dorsolateral PFC activity during STW and DTW.Patients with higher acute pain intensity and better coping skills demonstrated slower and less variable gait, which might reflect a pain minimization strategy. Psychosocial factors seem to play no or only a minor role, while good executive functions might be a prerequisite for a better gait performance in CLBP patients. The specific associations between gait parameters and PFC activity during walking indicate that the availability and utilization of brain resources are crucial for a good gait performance. While iWhile CLBP is usually a consequence of anatomical or physiological anomalies , the psyIn general, walking is a highly automatized motor activity that, depending on the demands, requires more or less additional attentional and cognitive resources . These dAdditionally, it has been demonstrated that the prefrontal cortex (PFC) is not only involved in executive functioning, but also in pain processing  and prioThe objective of the present study was to determine the relationships between spatio-temporal gait parameters recorded during single task walking (STW) as well as dual task walking (DTW) and acute/chronic pain intensity, psychosocial aspects, executive functions as well as PFC activity during walking in CLBP patients.We hypothesized that, due to the effect of CLBP on physical and cognitive functions, higher acute and chronic pain intensity is associated with shorter stride length, slower gait velocity and higher variability of these parameters. Given that the minimum toe clearance (MTC) and its variability do not seem to be affected by CLBP , no corr2.2.1.The cross-sectional data presented in this article were acquired in the context of a longitudinal study investigating the effects of a multimodal exercise intervention on physical and cognitive functions in patients with CLBP (see study protocol for further information ). The pr2.1.1.The sample size for the above-mentioned longitudinal study has been calculated using G*Power (version 3.1.9.7.). For the respective study, two groups and two covariates were planned. The calculation considered an α-level of 0.05 and a power of 0.95 resulting in a total sample size of 84 participants. Assuming a dropout rate of 15%, a sample size of 100 patients was considered appropriate .2.1.2.via an advertisement published in a local newspaper. In total, 243 CLBP patients were invited per telephone to the Medical Care Centre Klinikum Magdeburg for a medical anamnesis. There, the patients were treated by an orthopaedist and were recruited based on the following inclusion criteria: (i) ≥ 50 years old, (ii) average LBP score greater than 4 on a numeric rating scale , (iii) lasting LBP symptoms for more than 3 months and (iv) diagnosed to suffer from CLBP according to the International Classification of Diseases 10th revision .The patients were recruited from July 2020 to January 2021 CLBP patients were excluded if they: (i) had more than two previous spine surgeries, (ii) had more than three spinal segments fused, (iii) had any surgical intervention during the previous 6 months, (iv) were unable to walk without an aid, (v) had strength reductions higher than 25% according to Janda’s muscle function diagnostic , (vi) haFinally, 111 CLBP patients  met the specific requirements. They were asked to sign a written informed consent and also received four questionnaires: The German version of the Tampa Scale of Kinesiophobia (TSK), the German Freiburger Questionnaire on Physical Activity, the German Pain Questionnaire  and the Coping Strategies Questionnaire German version (CSQ). The questionnaires were used to assess the fear of movement related to pain, the level of daily activity, demographic and chronic pain related data  and fina2.2.Approximately 3 weeks after the anamnesis, the patients were invited to the OvGU laboratory for the experimental session. They were asked to fill the above-mentioned questionnaires the day before. Because of the time delay, all criteria were again checked before the measurements. Among the 111 CLBP patients initially recruited, 108  participated in our experiment. Two patients had to be excluded due to their rating of chronic pain below 4 on the NRS and one due to dementia.Firstly, the participants were informed in detail about the test protocol. Then, they completed four additional German questionnaires  and the Fatigue Subscale Profile of Mood States to assess the back pain associated disability in daily life, the health-related quality of life, the level of depression and state fatigue, respectively). Thereafter, the first executive performance test, the paper and pencil version of the Color-Word-Interference Test , was perAfterwards, the subjects were equipped with the fNIRS cap to assess the activity of the PFC’s subareas . These areas were, respectively, selected for their involvement in pain processing and executive functioning , attentiAfterwards, the participants performed the TMT Part A and B as a measure of cognitive flexibility . The tes2.3.To simplify the readability, only those parameters considered to be correlated with the spatio-temporal gait parameters are presented and discussed below. That means, the focus is on the pain related data, TSK, CSQ, BDI-II, EFs and the fNIRS data. For the questionnaires, the Freiburger Questionnaire on Physical Activity, the Oswestry disability index, the EuroQol and the Fatigue Subscale Profile of Mood States have been omitted. Additionally, the static postural control data as well as the physical tests  have also been omitted from this study.2.3.1.The intensity of acute and chronic pain was assessed with an NRS from 0 to 10 provided in the GPQ. To assess the fear of movement, we used the short version of the TSK  consisti2.3.2.The EFs are defined as higher-order cognitive skills coordinating the subjects’ thoughts and actions towards the accomplishment of a specific goal  and theywith  B and A . Thus, a2.3.3.A block design was used for the fNIRS recordings . Followi2.3.4.The IMUs were placed on the proximal part of each foot. Based on 3D acceleration and gyroscope data, spatio-temporal gait parameters were calculated using the algorithm developed by Hamacher et al. . The out2.3.5.The fNIRS system uses the properties of the oxygenated (HbO) and deoxygenated (HbR) hemoglobin to absorb light at different spectra, to measure relative changes in HbO and HbR concentrations in neuronal tissue, which is related to brain activity . To do sTo assure an optimal fitting of the cap, the Cz point  was centrally positioned between nasion to inion and between the left and right preauricular points. Additionally, a darkening cap was applied on top of the diodes to avoid interference from ambient light. This set up allowed to capture the haemodynamic signal of the, respectively, left, right and medial area of the DLPFC Brodmann area 9 and 46  and FPC Brodmann area 10 (BA10) as well as the left and right Broca Brodmann area 45 (BA45). These subareas were composed of the following channels: left DLPFC BA9 , right DLPFC BA9 , medial DLPFC BA9 (channel 19), left DLPFC BA46 (channel 13), right DLPFC BA46 (channel 6), left FPC BA10 , right FPC BA10 , medial FPC BA10 (channel 9), left Broca BA45 (channels 15 and 16) and right Broca BA45 (channels 2 and 3).hmrR_PreprocessIntensity_NAN function to suppress non-existing values, then the hmrR_PruneChannels function to exclude channels whose signal was either below hmR_Intensity2OD function. To minimize motion artifacts, the signal was filtered using the hmR_MotionCorrectSplineSG function  based on a spline interpolation and the Savitzky-Golay filter  and to minimize the proportion of oscillations associated with vascular endothelial function (high pass filter: 0.01 Hz) , was applied to determine individual haemodynamic responses by the general linear model approach   and MATLy filter . A 3rd o0.01 Hz) . Finally patient . Lastly,approach . For thiAfterwards, the data were post processed in MATLAB. The first 5 s have been cut out due to the time delay of the hemodynamic responses –51 and t2.4.r was used. In all other cases, the Spearman’s rank-order correlation coefficient ρ was determined. Except for the fNIRS data, the MTC and its variability, all correlations have been calculated using one-tailed tests due to our directional hypotheses. Since multiple patterns of PFC hemodynamic have been observed during the execution of cognitive and/or motor tasks  with a significance level set at p < 0.05. Lastly, according to the results of the Kolmogorov-Smirnov test, either a paired t-test or a Wilcoxon rank test has been performed for the spatio-temporal gait parameters, the arithmetic task and the fNIRS data to assess the difference between the STW and DTW . Normal distribution of data was checked using the Kolmogorov-Smirnov test. Afterwards, correlation coefficients between the spatio-temporal gait parameters recorded during STW as well as DTW and the demographic data , the questionnaire results , the arithmetic performance, the executive function test performance  and the fNIRS data for each task have been calculated. When both parameters were normally distributed, the Pearson’s product moment correlation coefficient or tasks , a two-tor tasks   and velocity  indicating that higher left DLPFC (BA9) activity resulted in longer stride length and faster gait velocity. The HbR concentration of the left DLPFC (BA46) and left Broca (BA45) recorded during DTW showed a small positive correlation with gait velocity . This suggests that an increment of left DLPFC (BA46) and left Broca (BA45) activity is associated with faster walking velocity during DTW. Regarding the HbR concentration during DTW, the right DLPFC (BA9) showed a small positive correlation with the MTC . Thus, the higher the activity of the right DLPFC (BA9), the lower was the MTC. Lastly, the left DLPFC (BA9) showed a small positive correlation with the velocity CoV  and a small negative correlation with the MTC CoV . This indicates that a higher left DLPFC (BA9) activity is associated with lesser velocity variability but greater MTC variability  displayed a moderate negative correlation with stride length , the lower the gait velocity CoV during STW and the shorter the stride length as well as the slower the gait velocity during DTW. For kinesiophobia, no correlations with spatio-temporal gait parameters were observed. However, consistent with our hypothesis, higher depression was associated with slower gait velocity during DTW. Third, as initially supposed, the better the CLBP patients performed in the executive function tests  and the arithmetic task, the better was the gait performance  during STW and DTW. Furthermore, mainly the activity of the DLPFC was correlated with the spatio-temporal gait parameters. More precisely, a higher activity of the left DLPFC (BA9) during STW and the left DLPFC (BA46) as well as left Broca (BA45) during DTW were associated with higher gait velocity. The activity of the left DLPFC (BA9) during STW was further related to longer stride length. Moreover, it was found that the lower the activity of the right DLPFC (BA9), the higher the MTC during DTW. Finally, it was observed that the lower the activity in the left DLPFC (BA9), the higher the gait velocity CoV and the lower the MTC CoV during DTW.4.1.In this study, chronic pain intensity was not associated with the spatio-temporal gait parameters and their variability during STW and DTW in CLBP patients. This result is not surprising, as the review by Koch and Hänsel  showed cRegarding acute pain, a negative correlation was found with velocity CoV during DTW. This relationship might be interpreted as an avoidance or minimization of pain by consciously adapting the gait pattern to reduce unwanted movements , 55. ImpKinesiophobia and depression showed none to small associations with gait performance, respectively. Although, these psychosocial factors are thought to contribute to the development of CLBP , they weInterestingly, the “ability to reduce pain” was negatively correlated with stride length CoV during STW as well as stride length and velocity during DTW. These data might indicate that people with a better ability to reduce pain adopt a gait pattern with smaller stride length variability, shorter stride length and slower gait velocity to minimize pain associated with walking.4.2.Yogev-Seligmann et al.  already 4.3.Although brain activity was measured in several brain areas of the PFC, the most relevant brain regions are the DLPFC (BA9 and BA46), because of its involvement in pain processing and executive functioning , the FPCData analysis revealed only significant small to moderate correlations of the gait parameters with the activity in the DLPFC (BA9 and BA46) and left Broca (BA45) during STW and DTW in CLBP patients. Accordingly, an increased brain activity in the left DLPFC (BA9) was moderately related to longer stride length and a faster gait velocity during STW. This is in contrast to the results of Holtzer et al.  who haveDuring DTW, an increased activity in the left DLPFC (BA46) and left Broca (BA45) was associated with higher gait velocity. Although Holtzer et al.  have notThese findings collectively indicate that the availability and utilization of prefrontal brain resources are crucial for optimal STW  and DTW  performance in CLBP patients. This assumption is further corroborated by the finding that a lower activity in the left DLPFC (BA9) was associated with a higher velocity CoV in the DTW condition indicating that a reduced brain activity capacity promotes a poorer gait performance.In contrast, a lower activity of the right DLPFC (BA46) was associated with higher MTC values during DTW indicating a better gait performance, since lower MTC values are assumed to increase the risk of tripping . Given tThese findings collectively indicate that the associations between PFC activity and gait measures probably depend on the level of automaticity. While gait measures susceptible to dual task interference, such as gait velocity, were positively related to brain activity during DTW in CLBP patients, this association was reversed for the MTC and its variability.5.Although correlations between gait performance and several aspects were found, these do not necessarily indicate causal relationships. Moreover, our patients had a higher age and, therefore, the results might not be valid for younger CLBP patients.6.A good walking performance is crucial for safe locomotion and activities of daily living. The present study investigated the associations between gait performance and pain intensity, psychosocial aspects, executive functions and the PFC activity while walking in CLBP patients. The understanding of the multiple factors, which could impair gait performance, can help clinicians and therapists in the treatment and rehabilitation of CLBP patients. Although the found associations do not indicate causality, it seems that interventions that reduce depression and increase executive functioning might be suitable to improve gait performance in CLBP patients.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 Medical Faculty of the OvGU Magdeburg. The patients/participants provided their written informed consent to participate in this study.TN: investigation, documentation, data analysis, original draft preparation and review and editing. MB: conceptualization, methodology, documentation, data analysis, original draft preparation and review and editing. K-CB: conceptualization, methodology, investigation, documentation, data analysis, original draft preparation and review and editing. RB: conceptualization, methodology, investigation, documentation and review and editing. SW: investigation, documentation, data analysis and review and editing. SL, VM, LB, XM, and LJ: investigation, documentation and review and editing. AW, KM, and SD: patient recruitment, documentation and review and editing. JF and LS: funding acquisition, conceptualization, methodology, data analysis and review and editing. All authors contributed to the article and approved the submitted version.MultiMove Project (number ZS/2019/10/101921) funded by the European Regional Development Fund (project code: ajdx9exId4 EFRE 11.000sz00.00.0. 19 133780 0).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.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Subclinical left ventricular (LV) dysfunction may occur in T2DM patients at the early asymptomatic stage, and LV reserve function is a sensitive index to detect subtle LV dysfunction. The purpose of our study is (1) to assess the LV reserve function using treadmill exercise stress echocardiography (ESE) in asymptomatic type 2 diabetes mellitus (T2DM) patients; (2) to explore the link of serum biological parameters and LV reserve function.This study included 84 patients with asymptomatic T2DM from September 2021 to July 2022 and 41 sex- and age-matched healthy controls during the corresponding period. All subjects completed treadmill ESE, LV systolic function-related parameters such as global longitudinal strain (GLS) and systolic strain rate (SRs), as well as diastolic function-related parameters such as E wave (E), early diastolic velocity (e′), E/e′ ratio, early diastolic SR (SRe), and late diastolic SR (SRa) were compared at rest and immediately after exercise. The difference between LV functional parameters after treadmill exercise and its corresponding resting value was used to compute LV reserve function. In addition, the associations of LV reserve function and serum biological parameters were analyzed.P < 0.001 and ΔSRs:0.78 ± 0.33 s−1 vs. 1.02 ± 0.28 s−1, P < 0.001) in the T2DM group were both lower than those in the control group. Glycated hemoglobin (HbA1c), N-terminal pro-brain natriuretic peptide (NTproBNP), waist circumference, and high-sensitive C-reactive protein (hsCRP) were identified as independent predictors of LV systolic reserve by stepwise multiple linear regression analysis.Patients with T2DM did not significantly vary from the controls in terms of alterations in LV diastolic reserve measures, the changes of LVGLS and SRs (ΔGLS: 2.19 ± 2.72% vs. 4.13 ± 2.79%, LV systolic reserve function, as measured by pre- and post-exercise differences in GLS and SRs were significantly impaired in patients with asymptomatic T2DM, whereas diastolic reserve remained normal during exercise and was comparable to that of the control group. This was different from previous findings. High levels of HbA1c, NTproBNP, hsCRP, and increasing waist circumference were independent predictors of LV systolic reserve. Patients with T2DM have twice the risk of developing cardiovascular disease (CVD) compared with healthy individuals, resulting in an increased risk of death from cardiovascular complications . In patiUsing conventional echocardiography, the first hallmark of DMCM was previously thought to be diastolic dysfunction and was described as typical HF with preserved ejection fraction (EF). However speckle-tracking imaging (STI) could detect subtle changes in LV systolic function earlier than the decrease in the LVEF . ConsequThe identification of biomarkers that accurately predict HF and cardiovascular events in T2DM could improve patient management, aid clinical trials, and highlight novel pathogenesis and therapeutic targets, leading to further improvements in clinical practice . Thus, iThe aims of this study were (1) to explore the clinical application of treadmill ESE combined with STI in assessing LV reserve function, and (2) to analyze the association of serum biological parameters and LV reserve function, which may facilitate early identification of the changes of LV function in asymptomatic T2DM patients.2.2.1.In a cross-sectional study design, we prospectively enrolled asymptomatic patients with T2DM and healthy controls during the period from September 2021 to July 2022. T2DM was diagnosed according to World Health Organization criteria . The excObtaining the basic data for all subjects including gender, age, mass, waist circumference, neck circumference, the waist–hip circumference ratio (WHR), hip circumference, smoking history, drinking history, and resting blood pressure. Serum biological data were collected during fasting and included the measurement of glucose (Glu), glycated hemoglobin (HbA1c), total cholesterol (TC), triglycerides (TG), high- and low-density lipoprotein cholesterol , high-sensitive C-reactive protein (hsCRP), effective glomerular filtration rate (eGFR), homeostasis model assessment of insulin resistance (HOMA-IR), and N-terminal pro-brain natriuretic peptide (NTproBNP). HOMA-IR is the product of fasting serum glucose and fasting serum insulin, calculated as lin/22.5 .The study was approved by the local ethics committee and was conducted in accordance with institutional policies, national legal requirements, and the revised principles of the Declaration of Helsinki.2.2.Using standard Bruce protocols, each subject completed a symptom-limited treadmill  exercise test . Subject2.3.All subjects underwent standard conventional echocardiography using an ultrasound system Vivid E95 equipped with an M5S 3.5-MHz transducer  at rest and immediately after exercise in the left lateral decubitus position. Briefly, at rest and immediately after exercise, at least five periods of two-dimensional images(frame rate >70 frames/second) were obtained from the apical four-, three-, and two-chamber sections and digitally stored.Both groups complete a comprehensive 2D echocardiographic assessment at rest, according to guidelines of the American Society of Echocardiography(ASE) and the European Association of Cardiovascular Imaging(EACVI), all conventional echocardiographic and Doppler measurements of LV function were analyzed . LVEF waElectrocardiogram-triggered echocardiographic data were collected for 2D strain analysis with EchoPac . Using Automated Function Imaging to analyze the LV longitudinal function in three apical views . For optimal tracking results, the speckle region of interest was carefully modified. Segments that did not track adequately were manually readjusted, and if this was ineffective, they were removed from future research. Peak global longitudinal strain (GLS), peak systolic SR (SRs), peak early diastolic SR (SRe), and peak late diastolic SR (SRa) for the LV myocardium were determined . The mea2.4.The difference between resting and post-exercise LVEF, GLS, SRs, and s′ values were used to compute the LV systolic reserve function . The difference between resting and post-exercise E, A, EDT, IVRT, e′, a′, E/e′, SRe, and SRa was used to compute the LV diastolic reserve function .2.5.t-test was adopted to perform the comparison between two groups, and a paired t-test was used for within-group comparisons at rest and after exercise; for data that did not conform to normal distribution, a Mann-Whitney U test was adopted to perform the comparison between two groups, and Wilcoxon rank sum test was adopted for comparisons within a group. The Chi-square test was used to evaluate categorical variables. For correlation analyses, Pearson correlation was used for data that conformed to normal distribution, and Spearman correlation was used for data that did not conform to normal distribution. Independent influence factors of LV reserve function were analyzed by stepwise multivariable regression. P < 0.05 was considered to be statistically significant.Statistical analyses were conducted using SPSS for Windows , and all continuous variables in the study were presented as mean ± standard deviation or median and interquartile range. Categorical variables are expressed as frequencies and percentages. The normality of all continuous variables was evaluated by the Shapiro-Wilk test to satisfy the assumptions of subsequent tests. For data that conformed to normal distribution, an independent-sample 2.6.To evaluate the reliability of STI-related parameters at rest and immediately after exercise, we randomly selected 10 subjects. The first and second researchers independently re-analyzed the images one week after the initial analysis, without knowledge of the original results. This study was done to assess inter- and intra-observer variability by intra-class correlation(ICC). The intra-observer and interobserver ICC of GLS at rest were 0.94 and 0.93, respectively. The intra-observer and interobserver ICC of GLS after exercise were 0.93 and 0.92, respectively.3.3.1.P > 0.05). The T2DM group had larger neck, waist, and hip circumferences, as well as a higher WHR than the healthy controls (P < 0.05). For biological parameters, TC, TG, LDL-C, HDL-C, hsCRP, and eGFR in T2DM group were not different from the control group (P > 0.05). However, the T2DM group had higher levels of Glu, HbA1c, HOMA-IR, and NTproBNP compared with those in the control group (P < 0.05). This study involved 100 asymptomatic T2DM patients and 50 control subjects, after which 84 asymptomatic T2DM patients and 41 control subjects entered the analysis. The selection criteria are shown in the flowchart 3.2.P > 0.05). LVEF in the T2DM group was comparable to that in the control group (P > 0.05).3.3.P > 0.05) at rest, but the T2DM group had significantly higher levels of A, a′, and E/e′ (P < 0.05) at rest. Compared with the control group, e′ were markedly decreased in the patients with T2DM (P < 0.05) at rest, but these parameters were still within the normal range according to current guideline (P > 0.05). ΔE, ΔA, ΔEDT, ΔIVRT, Δe′, Δa′, ΔE/e′, ΔSRe, and ΔSRa did not significantly differ between the two group , but significant differences were revealed after exercise (P < 0.05). Although the differences in ΔEF and Δs′ were not significant between the two groups(P < 0.05), ΔGLS and ΔSRs were both lower in the T2DM group compared with those in the control group , and ΔSRs was modest independently correlated with NTproBNP , waist circumference , and hsCRP  through the stepwise multiple linear regression analysis.In 4.This study provides a thorough analysis of LV reserve function in asymptomatic T2DM patients, which is crucial for understanding the development of HF. Furthermore, we looked into the link between biomarkers and myocardial function in T2DM, enabling early detection of changes in LV function. A first principal outcome of the study was that asymptomatic T2DM patients have the similar GLS and SRs at rest to the controls. In contrast, compared to the control group GLS and SRs rose less during exercise in the T2DM group, whereas the changes in E/e′, E, A, EDT, IVRT, a′, e′, SRe, and SRa during exercise were similar in two groups. This suggests that LV systolic reserve impairment might appear early before diastolic reserve impairment. Our second major finding was that the primary contributors to these patients' decreased systolic response to treadmill ESE are high levels of HbA1c, NTproBNP, hsCRP and increased waist circumference, especially increased HbA1c level.T2DM is recognized as a separate CVD risk factor . T2DM an4.1.The complex factors of DMCM can lead to structural changes in the myocardium. LV hypertrophy and myocardial fibrosis are the earliest morphological changes that occur in patients with early and asymptomatic diabetes and can lead to diastolic dysfunction. Abnormal ventricular reserve function indicates subclinical ventricular dysfunction early. The ability of the LV to strengthen its diastolic function to preserve normal filling pressure during exercise is referred to as LV diastolic reserve function. Several studies of diastolic reserve in T2DM patients, which showed the differences in e′ and E/e′ were not significant between the two groups at rest. e′ velocity rose significantly less and the E/e′ ratio increased significantly more in the T2DM group during exercise, suggesting impaired diastolic reserve in this population , 18. Hen4.2.LV systolic function is instrumental in CVD. In our study, changes in LVEF were similar between the two groups both at rest and after exercise. Patients with asymptomatic T2DM showed similar results as the control group for LVGLS and SRs at rest. However, after exercise, LVGLS and SRs were significantly impaired in the T2DM group. Previous studies revealed that LVEF was not a sensitive index to identify subclinical LV systolic dysfunction, and a sensitive and feasible approach is to assess LV systolic function by GLS using STI . It is d4.3.For the prediction of incident HF and cardiovascular events in patients with T2DM and in those with existing HF and T2DM, we looked at how clinical features and serum biological markers affected LV systolic reserve. Based on univariate and multivariate correlation analyses, we identified the independent factors associated with LV systolic reserve. Parameters related to LV systolic reserve function are associated with the markers of diabetes metabolism, visceral adiposity, and the cardiovascular system. In particular, HbA1c, an indicator of glycemic control, showed an independent and significant correlation with ΔGLS.In diabetic patients, HbA1c offers an indication of glycemic control over a period of two to three months, the standard for good glycemic control is HbA1c < 7% . HyperglOne of the measures of abdominal adiposity is waist circumference which was found to be independently and mildly associated with LV systolic reserve function in our study. Previous studies have found that increased abdominal obesity is independently associated with impaired left ventricular systolic function, regardless of the presence of systemic obesity . The mecThe collective findings of these studies emphasize the significance of effectively managing HbA1c, waist circumference, NTproBNP and hsCRP in the treatment of DMCM and in preventing the progression of DMCM from subclinical to overt stages. Particularly, maintaining good glycemic control is crucial.4.4.1.This study was a single-center study with a small sample size resulting in a high standard deviation of the measurement parameters. In addition, it is important to note that the results of this study are based on hypotheses.2.LV function is the result of multi-directional deformation  interacting with torsional mechanics. This study solely looked at longitudinal strain, and circumferential/radial strain and LV torsion angle (twist) need to be taken into consideration in future work. Furthermore, since the heart has a three-dimensional (3D) structure, its motion is also 3D. However, some of this information is inevitably lost because this research is based on 2D STI, resulting in a less comprehensive and less accurate assessment of myocardial strain.The limitations of this study are as follows:5.In this study, we found that asymptomatic patients with T2DM exhibited impaired systolic reserve function, while diastolic reserve function remained preserved. This finding contradicts previous suggestions that diastolic function is impaired first in DMCM. These results suggest that combining treadmill ESE with STI might be valuable in detecting subtle myocardial injury in asymptomatic T2DM patients. Furthermore, HbA1c, waist circumference, NTproBNP and hsCRP are independent predictors of the blunted systolic function which results in an inadequate response to treadmill ESE in these patients. Good control of these parameters, particularly HbA1c levels, might be beneficial for LV systolic reserve function.


Cardiovascular self-organized criticality has recently been demonstrated. We studied a model of autonomic nervous system changes to better characterize heart rate variability self-organized criticality. The model included short and long-term autonomic changes associated with body position and physical training, respectively. Twelve professional soccer players took part in a 5-week training session divided into “Warm-up”, “Intensive”, and “Tapering” periods. A stand test was carried out at the beginning and end of each period. Heart rate variability was recorded beat by beat (Polar Team 2). Bradycardias, defined as successive heart rates with a decreasing value, were counted according to their length in number of heartbeat intervals. We checked whether bradycardias were distributed according to Zipf’s law, a feature of self-organized criticality. Zipf’s law draws a straight line when the rank of occurrence is plotted against the frequency of occurrence in a log–log graph. Bradycardias were distributed according to Zipf’s law, regardless of body position or training. Bradycardias were much longer in the standing position than the supine position and Zipf’s law was broken after a delay of four heartbeat intervals. Zipf’s law could also be broken in some subjects with curved long bradycardia distributions by training. Zipf’s law confirms the self-organized nature of heart rate variability and is strongly linked to autonomic standing adjustment. However, Zipf’s law could be broken, the significance of which remains unclear. Maintaining internal conditions is a primary physiological challenge for all organisms, and this is achieved through the stability of body constants ,2. It isAn alternative concept for physiological homeostasis has been proposed from the field of physics. In the late 1980s, Per Bak identified a pile of sand as a dynamic system spontaneously poised at equilibrium without the need to tune any control parameter to a precise value ,8,9. TheThe interesting point is that systems near to criticality can more easily adjust to changes in environmental conditions ,5,10. CrIn the cardiovascular system, major events include vasovagal syncope, which may occur spontaneously in the standing position, even in healthy individuals . We prevCardiovascular adjustment to the standing position is mainly due to the autonomic nervous system ,14. To bThe study involved twelve professional male soccer players, with an average age of 24.9 ± 1.5 years (mean ± SEM). The players had normal characteristics, with an average height of 1.77 ± 0.03 m and weight of 75 ± 1.3 kg. Informed consent was obtained from all participants, and the procedures were approved by the Ethics Committee of Angers, France  in accordance with the Declaration of Helsinki, Finland.Heart rate variability monitoring was achieved by using a sports watch on a beat-by-beat basis with a one-millisecond resolution for RR interval measurements . Continuous heart rate recordings were obtained during stand tests that consisted of a ten-minute supine period followed by a seven-minute period in the standing position. The stand tests were performed at 8:30 am, before breakfast. Four stand tests were conducted for each player during a five-week preparation period for the competition season, after the season break. The preparation period included three phases: a two-week “Warm-Up” period, followed by a two-week “Intensive” training period, and finally a one-week “Tapering” period. The first standing test took place after the season break and before the training period. The three subsequent standing tests were conducted at the end of each phase of the training period. Individual performance was not assessed in this experiment due to the absence of a known objective measurement to evaluate it within the context of a so-called team intermittent sport. In soccer, performance relies primarily on abilities rather than aerobic capacity and is influenced not only by physical fitness but also by situational factors such as tactics, scoring, and refereeing .Heart rate recordings were analyzed during stand tests to obtain the mean heart rate in both the supine and standing positions. Additionally, five-minute heart rate recordings were analyzed in both positions to detect bradycardia sequences and determine their distribution according to Zipf’s law. A bradycardia sequence was defined as successive heartbeat intervals with a decreasing heart rate value. For each five-minute recording, bradycardia sequences were counted and classified by their length in number of heartbeat intervals. The rank of bradycardia sequences of the same length was determined by classifying them according to their frequency of occurrence. A natural log–log diagram was plotted for each five-minute heart rate recording, with the number of sequences on the x-axis and their rank on the y-axis. Linear regression was performed for each diagram to obtain correlation coefficients and slopes. In cases where diagrams showed a tipping point, its position was determined by the best linear fit.p < 0.05.Data were presented as the mean ± standard error of the mean (SEM). Statistical analyses were conducted using Prism 8 software . We considered that a Zipf’s graph distribution would fit a straight line when the absolute value of the correlation coefficient |r| exceeded 0.95, as this high cut-off is commonly used to test for power laws ,12,13. TThe quality of the data collected during this field experiment was good, as demonstrated in Heart rate decreased with each stage of training; the decrease was significant from the end of the warm-up period but remained unchanged thereafter . As expeThe number of heartbeat intervals involved in bradycardia remained unchanged during the training period . HoweverThe bradycardia distribution diagrams showed a short range of distribution in the supine position a, extendThe range of bradycardia distribution was much larger in the standing position, extending to 10.9 ± 0.9 heartbeat intervals b. A tippThe slope of the short bradycardia distribution was not affected by training, while position had a significant impact .2 = 0.04; p = 0.24).Given the similarity in the strong effect of position on this slope and that of heart rate, we sought to establish a correlation between these two variables. We observed a high correlation between position and heart rate . The sloThe primary finding of this study is that changes to the autonomic nervous system in response to body position strongly influence cardiovascular self-organized criticality. Specifically, the use of Zipf’s law provides evidence of the impact of standing position on heart rate variability recordings.Professional soccer players are high-performance athletes and cannot be compared to the general population. However, training high-level sport teams provides an exceptional opportunity to conduct long-term experiments on highly motivated and relatively homogeneous groups of healthy individuals. Monitoring heart rate variability in athletes is important for optimizing training, making it an excellent opportunity for studying long-term cardiovascular adjustments . The preThe description of heart rate variability in the 1980s challenged the traditional foundation of physiology based on homeostasis, negative feedback regulatory loops, and the stability of bodily constants ,19. HomeThere is no single robust way to demonstrate the self-organized criticality of a dynamic system ,9, as thMost studies examining Zipf’s law in heart rate variability have used Holter recordings ,27,28. AOur study provides clear evidence that Zipf’s law is observed in heart rate variability for the standing position, while the results were less conclusive for the supine position. The range of straight lines is limited to a delay of a few beats in the former position. Moreover, alterations of the slope of these bradycardia sequences limited to few beats probably only reflect heart rate alterations since these two variables are strongly correlated. On the contrary, the slope of long bradycardia is not correlated with heart rate and this slope could indicates changes in criticality. This point is supported by the findings of our previous research on vasovagal syncope, which showed that patients with syncope have an increased slope of long bradycardia distribution .The effects of autonomic nervous system adjustments on heart rate due to training are typically noticeable, but their impact on heart rate variability is more challenging to observe, regardless of the analysis tool used ,18. In oWe have previously reported that the cardiovascular Zipf’s law is violated at a delay of four heartbeat intervals, with the underlying reasons remaining unclear . Our recOur study provides robust evidence for the existence of Zipf’s law in heart rate variability, supporting the notion of cardiovascular self-organized criticality. However, we also observed instances where Zipf’s law was broken, emphasizing the need for further research to elucidate its significance. Moreover, our study introduces a user-friendly tool for characterizing the intricate dynamics of the cardiovascular system, which could potentially aid in the diagnosis of heart rhythm disorders in clinical settings .


In addition, the professional players had lower GCW (p = 0.003) and a tendency to show lower GWI values (p < 0.001). These findings could suggest that professional football players have more remodeling and less MW, related to their adaptation to intensive training. Significant differences in GLS (p = 0.01) and GWE (p = 0.04) were observed as a function of the septal thickness of the athletes. Irrespective of the MW variable, the parameters with better correlations across all the populations were SBP, DBP, and GLS. Conclusions: The GWI is a novel index to assess cardiac performance, with less load dependency than strain measurements. Future GWI analyses are warranted to understand myocardial deformation and other pathological differential diagnoses.Background: The global myocardial work index (GWI), a novel, valid, and non-invasive method based on speckle-tracking echocardiography, could provide value for calculating left ventricular (LV) function and energy consumption in athletes. Materials and Methods: We prospectively analyzed a single-center cohort of Spanish First-Division football players who attended a pre-participation screening program from June 2020 to June 2021, compared to a control group. All the individuals underwent an electrocardiogram and echocardiography, including two-dimensional speckle tracking and 4D-echo. The study aimed to evaluate the feasibility of myocardial work in professional football players and its correlations with other echocardiographic parameters. Results: The study population comprised 97 individuals . The mean age was 30.48 ± 7.20 years old. The professional football players had significantly higher values of LVEDV ( Physical exercise and sports have demonstrated cardiovascular benefits . ParticiCommon cardiovascular diseases observed in athletes can be suspected based on an electrocardiogram (ECG), in which is a cost-effective test . HoweverSpeckle-tracking echocardiography (STE) is a relatively recent echocardiographic technique of deformation imaging that has provided new insights into the characterization of athletes’ myocardial properties . It can Myocardial work (MW) has been established recently as a new LV systolic-function index. It considers afterload based on strain and non-invasive LV pressure as a surrogate measure for overall myocardial consumption ,13. The Although these cardiac changes induced in athletes have been described in other sports, such as swimming or cycling, data regarding professional football players are scarce. Therefore, this study aimed to evaluate the feasibility of analyzing myocardial work in professional football players and its correlations with other echocardiographic parameters.We prospectively enrolled a single-center cohort of Spanish First-Division football players who had followed an intensive training schedule of more than 15 h a week for over five years. The control group was recruited from healthy hospital staff who did not undertake regular physical exercise. Both groups were in the same age range and were matched by body-mass index (BMI), and the recruitment period lasted from June 2020 to June 2021.Professional football players were selected after performing FIFA-mandated pre-participation health screening before competitions. As a result, all players presented similar training methods, emphasizing effort directed toward improving power and speed rather than endurance, despite some variability based on the players’ positions.Selection criteria for both groups included: (a) exclusion of metabolic diseases, including hypertension; (b) normal 12-lead ECG; (c) LV ejection fraction > 55%; (d) normal wall-motion-score index, and exclusion of myocardiopathy; (e) exclusion of genetic or congenital heart disease; and (f) exclusion of valvular or coronary pathology In addition, for the control group, (g) lack of regular exercise (cut-off pf less than 3 h a week) was applied.Professionals and controls underwent an ECG, standard echocardiography, and a complete clinical and laboratory evaluation. In addition, clinical data  were collected from medical records and entered with echocardiographic variables into an online electronic database, Redcap .Transthoracic echocardiography was performed using a commercially available ultrasound system  with 3.5-MHz M5Sc 2D and a 3D volumetric transducer (4 V) for real-time echocardiographic dataset acquisition of the ventricles. Two operators conducted 2D and 3D echocardiography on the same machine to avoid multiple-observer and inter-device variability and discrepancies in the techniques. Ultrasonic recordings and measurements were processed according to the European Association of Cardiovascular Imaging recommendations .Left-ventricular-internal-dimension diastole (LVIDd), diastolic interventricular septal thickness (IVSTd), and diastolic posterior-wall thickness (PWTd) were obtained in the parasternal long-axis section of LV. Relative wall thickness (RWT) was computed using the ratio (IVSTd + PWTd)/LVIDd). The LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (EF) were calculated using Biplane Simpson’s method. Valvular regurgitation was quantified from color Doppler imaging and categorized as absent, minimal , or mild using the vena contracta method.Quantification of 2D strain was performed using commercially available software . The analysis was performed in all three apical views . The operator assessed the tracking quality and scores were compiled by the software with an automated function in the region of interest, which was adjusted by correcting the endocardial border or width if deemed necessary.Aortic valve closure was identified using the automated function from the apical long-axis view. The GLS was calculated by averaging local strains of all 16 segments and expressed as bull’s-eye. If the software did not correctly identify the LV-wall movement without assigning a strain value to the LV segment (poor tracking), the operator repeated the process, readjusted the endocardial tracing, or changed software parameters, such as region of interest (ROI) width and smoothing until a better score was achieved.Global myocardial work index (GWI) was calculated using a specific software with a combination of LV strain and a non-invasively estimated LV pressure with systolic cuff pressure. Peak systolic LV pressure was assumed to be equal to the peak arterial pressure, measured immediately before the echocardiographic study. The software constructed a non-invasive LV-pressure curve, which was adjusted according to the duration of isovolumic and ejection phases defined by valvular-timing events. The area within the curve was an index of MW. An additional set of indices was used: global constructive work (GCW), defined as myocardial work performed during segmental shortening; and global wasted work (GWW), defined as work performed by the LV that does not contribute to LV ejection, characterized by the lengthening of myocytes during systole, with addition of shortening during the isovolumic relaxation phase; and global myocardial work efficiency (GWE), calculated as constructive MW/(constructive MW + wasted MW) (0–100%) .The proposed ranges for non-invasive MW in the NORRE  study were used as normality-reference values .Beyond routine echocardiographic protocol, electrocardiographically gated full-volume 3D data sets, reconstructed from four or six cardiac cycles optimized for the LV, were obtained from apical view, with a minimum volume rate of 25 volumes/sec, for offline analysis. The quality of images was verified to avoid “stitching” and “dropout” artifacts in the 3D data. Further measurements were performed on a separate workstation using dedicated software.t-test and Mann–Whitney U) and nonparametric  tests were applied to contrast means. Correlations between the continuous variables of MW , standard echocardiography, and advanced echocardiography were calculated using Pearson’s or Spearman’s correlation coefficient, as appropriate. Chi-square tests were used to evaluate the association between valvular regurgitations and the number of alterations as a function of amateur- or professional-player status and field position. Finally, binary logistic regression analyses were performed, in which the dichotomous dependent variables were the presence of valvular regurgitation and more than one alteration in the subsample of professional players. All statistical analyses were carried out using SPSS version 25.The normality of the distribution of continuous variables was tested using the Kolmogorov–Smirnov test. Continuous variables were expressed as means and standard deviation (SD). Parametric . The demographic data, standard echocardiogram, left-ventricular myocardial work, and strain parameters of the professional football players and controls are summarized in p < 0.001), LVESV (p < 0.001)), mass index (p = 0.011), and PWTd (p = 0.023). At the same time, the LVEF values showed a minimal reduction without statistically significant differences. No regional wall-motion abnormalities were identified. Concerning the trans-mitral Doppler index, the professional players showed higher mitral E velocities and EA ratios (p < 0.001), as well as lower values for lateral E/E’ (p = 0.008).In the standard echocardiographic measurements, the professional football players presented higher values for LV (LVEDV (p = 0.030) in the professional players, who had lower GCW (p = 0.003) than the control group and a tendency to lower values for GWI. The GWE did not show significant differences between the two groups.The professional footballs presented higher right ventricular (RV) volumes in the advanced echocardiographic measurements, while the RV functionality did not show statistically significant differences. A 2DSTE analysis showed a mild reduction in LV GLS  and presented higher RVEDV (p = 0.007) and RVESV (p = 0.010). Regarding the MW, there was a certain tendency towardhigher GCW and GWW in the subjects with greater alterations.There were no significant differences between the demographic and echocardiographic characteristics according to the positions of the players on the field . Possiblp-values close to significance (p < 0.05). In these specific cases, extreme caution should be exercised, as we cannot establish a trend until we observe how these variables behave in larger samples.It should be noted that, given the sample sizes of both groups , there were numerous variables with For the professional football players, the best correlations for GWI, GCW, GWW, and GWE are shown in p = 0.01) and GWE (p = 0.04) were observed as a function of the septal thicknesses of the athletes. Those with IVSTd < 10 mm presented higher GLS values  and higher GWE values  than those in whom IVSTd = 10–13 mm  .Significant differences in GLS (p < 0.001). This imbalance was also observed in the number of cardiac alterations, which were present in 83.7% of the football players versus 14.6% of the controls. The significant or near-significant results of the binary logistic regression models are shown in p = 0.020) and of presenting more than one alteration by 1.527 times (p = 0.056).The proportion of valvular regurgitations  was unbaStandard echocardiography has an essential role in assessing the characteristics of the athletes´ hearts, differentiating physiological and pathological LV remodeling . The hemThe 2DSTE analysis showed a mild but statistically significant reduction in LV GLS in the professional football players, who displayed lower significative GCW than the control group and a tendency toward lower GWI values, associated with normal biplane LVEF. These findings suggest that professional football players have greater anatomical cardiac remodeling, less deformation, and lower myocardial work indices due to their adaptation to more intensive training.It is remarkable that when using normality-reference values of myocardial work , the proAlthough we could not find a significant difference in the GLS and BP between both groups, and even found a higher LV-mass index among the professional football players, this could have been determined by the intraventricular thickness differences between some of the LV segments. To this end, we performed an exploratory analysis, identifying an interesting finding: the professional players with an IVSTd of 10–13 mm presented poorer GLS  and GWE  values than their counterparts with left-ventricular septal thicknesses of less than 10 mm. Indeed, it is well-known that some trained individuals have an increased septal thickness , which mp < 0.001). Nevertheless, the regurgitation was generally mild and not clinically significant. Similarly, in a previous study, an increased prevalence of regurgitant flow was noted [Additionally, we observed an association between professional football practice and mild pulmonary and tricuspid insufficiency  the small sample size and statistical power, which reduced the likelihood of reaching definitive conclusions; (ii) the lack of a myocardiopathy cohort, which might have allowed a better differentiation between the physiological and pathological adaptations; and (iii) a lack of cardiopulmonary test values, which might have helped form a better understanding of the findings of this work. However, our study has a strength, in that it is the first study to present an analysis of MW in a cohort of professional football players with identical degrees of training and, therefore, a similar cardiovascular demand, during the same period. Nevertheless, further investigations are warranted.The MW is a novel index of LV systolic function that provides new insights into athletes’ myocardial properties. However, further evidence is needed to refine MW diagnostic performance and make it part of the standard diagnostic workup and differential diagnosis of other pathological conditions.


Atrial function can be assessed using advancing cardiovascular magnetic resonance (CMR) post-processing methods: atrial feature tracking (FT) strain analysis or a long-axis shortening (LAS) technique. This study aimed to first compare the two FT and LAS techniques in healthy individuals and cardiovascular patients and then investigated how left (LA) and right atrial (RA) measurements are related to the severity of diastolic dysfunction or atrial fibrillation.Sixty healthy controls and 90 cardiovascular disease patients with coronary artery disease, heart failure, or atrial fibrillation, underwent CMR. LA and RA were analyzed for standard volumetry as well as for myocardial deformation using FT and LAS for the different functional phases . Additionally, ventricular shortening and valve excursion measurements were assessed with the LAS module.p < 0.05) between the two approaches, with the highest correlation coefficients occurring in the reservoir phase . Both methods demonstrated reduced LA  and RA reservoir function  in patients compared to controls. Atrial LAS and FT decreased with diastolic dysfunction and atrial fibrillation. This mirrored ventricular dysfunction measurements.The measurements for each of the LA and RA phases were correlated (Similar results were generated for bi-atrial function measurements between two CMR post-processing approaches of FT and LAS. Moreover, these methods allowed for the assessment of incremental deterioration of LA and RA function with increasing left ventricular diastolic dysfunction and atrial fibrillation.A CMR-based analysis of bi-atrial strain or shortening discriminates patients with early-stage diastolic dysfunction prior to the presence of compromised atrial and ventricular ejection fractions that occur with late-stage diastolic dysfunction and atrial fibrillation.• Assessing right and left atrial function with CMR feature tracking or long-axis shortening techniques yields similar measurements and could potentially be used interchangeably based on the software capabilities of individual sites.• Atrial deformation and/or long-axis shortening allow for early detection of subtle atrial myopathy in diastolic dysfunction, even when atrial enlargement is not yet apparent.• Using a CMR-based analysis to understand the individual atrial-ventricular interaction in addition to tissue characteristics allows for a comprehensive interrogation of all four heart chambers. In patients, this could add clinically meaningful information and potentially allow for optimal therapies to be chosen to better target the dysfunction.The online version contains supplementary material available at 10.1007/s00330-023-09663-4. Left ventricular (LV) diastolic dysfunction is a highly prevalent condition that is associated with ventricular and atrial remodeling and has strong associations with heart failure and atrial fibrillation (AF) , 2. LA vFunctional assessment is commonly performed using dimensions or volumes. However, volumetric analysis either requires complete coverage of the chamber, which is time-consuming, or relies on geometric assumptions when using fewer image planes. A different approach is through deformation analysis, or strain imaging, which can be performed for the atria using echocardiography, computed tomography, or cardiovascular magnetic resonance (CMR) –8. FeatuThus, this study aimed to investigate and compare atrial FT and LAS CMR analysis approaches for atrial function in healthy controls and how they compare to cardiovascular disease patients with diastolic dysfunction and atrial fibrillation (AF).Sixty healthy controls and ninety cardiovascular disease patients with either heart failure , paroxysImages were obtained with a 3.0-Tesla clinical scanner . Retrospective-gated cine images with 25 − 30 phases were acquired in short-axis and long-axis views orientated to the left ventricle. In the case of varying RR intervals, gating was changed to prospective triggering at the discretion of the imaging technician. T1 maps (5(3)3-modified look-locker inversion recovery) were acquired in three short-axis views. In cardiovascular patients, 0.1–0.15 mmol/kg of contrast agent , was administered and T1 maps were reacquired post-contrast for the assessment of extracellular volume (ECV) while late gadolinium enhancement (LGE) images were acquired for assessment of focal scar.42 . Ventricular parameters were measured as previously described [All images underwent a second level of coding to blind the reader from the originating study and site, disease status, and other variables. Analysis was performed with cviescribed , 17.reservoir phase indicating the filling phase of the atria from minimal to maximal volume, strain, or extent, occurring during ventricular systole. This is also known as the atrial peak strain and the change in volume over this phase is used to calculate the atrial ejection fraction.The conduit phase comprised of passive atrial emptying, occurring during early ventricular diastoleThe booster phase for active atrial emptying, also known as the atrial kickThe Atrial strain analysis was performed using FT. Epicardial and endocardial contours were placed on LA on both the four-chamber (4CH) and two-chamber (2CH) views, and on RA of the 4CH view on a single phase at ventricular end-diastole. For both atria, the free wall and the atrial septum were included in the measurements Fig. . EndocarUsing the 2CH and 4CH cines, contours defining the LA and RA endocardium, LV endo- and epicardium, and valvular junctions were drawn automatically using a machine learning algorithm of the module for each phase of the cardiac cycle. Each image was reviewed by the reader and adjusted manually if required. Biplanar atrial areas and volumes were calculated. LA and RA long-axis shortening (LAS) were calculated from the longitudinal shortening of the atria from the atrial roof to the center of the atrioventricular valve Fig. D for eac p value of  < 0.05. GraphPad Prism version 8.0  were used for statistical analysis.First to compare the atrial analysis techniques, measurements from the atrial biplanar volumetric analysis, FT strain and LAS, were compared using correlation analysis. Agreement between techniques was further tested with the Bland-Altman analysis. Findings were first compared between the healthy controls and the entire patient group using a general linear model including age as a covariate. To further account for age differences between patients and healthy controls, a subgroup of healthy controls consisting of only the oldest tertile was defined. This older control subgroup was then compared to the diastolic dysfunction patient subgroups using ANOVA and post hoc analysis accounting for multiple comparisons. Logistic regression was used to quantify the area under the curve (AUC) to investigate the ability of atrial measurements to discriminate the patient subgroups. Statistical significance was defined with a two-sidedn = 12, persistent n = 8). The remainder had normal diastolic dysfunction or were not classified. Heart failure was diagnosed in n = 53 (59%) of the total cohort and was frequent in the diastolic dysfunction grade I , grade II/III , and AF subgroups . Heart failure with preserved ejection fraction (HFpEF) was more common than heart failure with reduced ejection fraction (HFrEF) in both diastolic dysfunction grade I (HFpEF = 71% vs HFrEF = 29%) and diastolic dysfunction grade II/III (HFpEF = 94% vs HFrEF = 6%). The opposite was seen in patients with AF with a higher prevalence of HFrEF (HFpEF = 37% vs HFrEF = 69%). None of the patients with normal diastolic function had heart failure .Detailed participant characteristics are provided in Supplemental Table The left ventricular analysis could be acquired from all 150 datasets. Concerning the LA, nine patients were excluded from the analysis because 2CH and 4CH views were off the plane with foreshortening, in which both the atrial roof and the middle of the valve were not visible. Thus, 94% of the cines were available for analysis. All remaining images could be analyzed for volumetric and rapid LAS atrial analysis, with 84% eventually being usable for FT analysis after excluding another seven for tracking errors. Similarly for the RA, sixteen images were excluded due to plane position, thus 89% were usable for volumetric and atrial LAS measurements which could be performed on all appropriate planes, with 81% eventually being usable for the FT strain analysis  or AF , similar comparisons were observed between the two techniques  and AF . Significant, but weaker linear relationships were observed for the conduit and booster atrial phases.Correlograms in Fig. p < 0.05). On the other hand, significant reductions in LA ejection fraction only occurred with the grade II/III diastolic dysfunction and AF subgroups , the patient subgroups with diastolic dysfunction  or AF (FT: 14 ± 11% and LAS: 15 ± 11%) had a significantly reduced reservoir strain  and long-axis shortening (LAS) post processing analysis methods provided consistent results for left and right atrial measurements in a cohort of 150 controls and cardiovascular patients. Even in diastolic dysfunction or AF, these atrial analysis techniques were comparable. Moreover, both methods demonstrated reduced atrial movement in patients with diastolic dysfunction and atrial fibrillation. These reductions in atrial function measured by FT and LAS were able to discriminate patients with less severe stages of diastolic dysfunction whereas changes in common volumetric analyses including atrial ejection fraction did not appear until later stages.These findings indicate that both FT-strain and LAS measures may allow for detecting atrial abnormalities at an early stage of disease, consistent with echocardiography investigations , 18, 19.The key advantage of the FT and LAS techniques in comparison to volumetry is that they can be analyzed using minimal planes. Mono-planar and bi-planar volumetric analysis is a calculated representation of the atrial volume based on lumen diameters and area assuming an ideal spheric geometry. For more accurate volumetric analyses, full-stack atrial imaging would be required. However, when using current segmented cine techniques these additional slices required for full coverage volume analysis add time to image acquisition and analysis; consequently, these new FT strain and LAS approaches offer a comprehensive analysis from a relatively parsimonious amount of data. In addition, these new approaches may be more sensitive than using biplanar volumetric assessment. Echocardiography studies have shown that LA peak strain is less load-dependent than atrial volumetry-derived function measurements . HoweverInterestingly, although our RA results show the same trends as in the LA data, significant findings were typically observed only with more severe diastolic dysfunction or AF. For instance, attenuated RA reservoir FT strain and LAS were not observed until diastolic dysfunction grade II/III was present, and no technique could discriminate diastolic dysfunction grade I from the RA. Pathophysiological explanations may be based on backward failure from progressive left-heart disease, or direct interventricular interactions. Since we categorized our groups by grading LV diastolic dysfunction, it appears logical that increased LV diastolic pressures first induce LA enlargement and dysfunction. Over time, this can cause a backward failure chain reaction with pulmonary venous congestion, eventually exposing the RV and RA to increased filling pressures. Direct left-to-right interactions may occur since all heart chambers are confined in the same non-distensible pericardium. Here, the advantage of interrogating all four chambers is that the function of each atrial and ventricular chamber can be assessed individually, also during identical phases of respiratory cycling, providing insight into the individual’s pathway of heart failure development. For example, in a recent pulmonary hypertension study, different atrial-ventricular interactions were observed in patients with pulmonary arterial hypertension secondary to HFpEF when compared with patients without HFpEF . It is iAtrial measurements are influenced by the dynamics of the atrio-ventricular interaction. Atrial reservoir (peak) function is dependent on both atrial stiffness and ventricular contractility during systole. On the other hand, conduit function is dependent on both atrial contractility and early LV relaxation. The ventricle is likely to play a larger role in atrial function in the early development of diastolic dysfunction. As the ventricle with diastolic dysfunction gradually stiffens, the atrium distends owing to increased atrial pressure, which in turn maintains blood flow into the ventricle in early diastole. We observed the earliest atrial FT-strain and LAS dysfunction during the LA reservoir phase (diastolic dysfunction grade I). This is consistent with previous findings from an echocardiography study where LA reservoir strain showed better agreement with invasively measured filling pressures, a hallmark of diastolic dysfunction, than the echocardiography marker E/e’ .The LAS analysis module applied in our analysis is also useful because it provides results for ventricular systolic function, i.e. TAPSE, MAPSE, and LV-LAS, which were analyzed simultaneously with the atria. In comparison to the LV ejection fraction, which was only abnormal in the AF group, ventricular LAS along with the valve tracking markers of MAPSE and TAPSE detected abnormal ventricular dysfunction as early as diastolic dysfunction grade I, in line with the atrial measures. A unique characteristic of CMR in comparison to echocardiography is that its findings can be linked with tissue characterization measurements, which also reflected increasing myocardial fibrosis with increasing grades of diastolic dysfunction indicating a stiff LV.This comparative study of atrial function assessments using the FT and LAS techniques indicated similar output, especially for the reservoir phase. Because LAS analysis was not solely reliant on tracking algorithms and contours could be manually adjusted, more patients could be included in the LAS analysis when compared to FT assessment of the same images. Especially in the case of AF, all images could be assessed for LAS. FT requires a good visualization of the entire atrial walls throughout the cardiac cycle, which made it prone to more errors and a higher user-defined exclusion rate. As LAS analysis is a simple calculation of chamber shortening, this can theoretically be performed by manual analysis as well without advanced post-processing software and presents an accessible option for imaging sites that do not have access to the newest software. A topic of further study might be to investigate time expenditure for each analysis method. Future work should assess these analysis techniques in relation to clinical patient status and outcomes and determine their prognostic utility in a larger cohort.Our classification of diastolic dysfunction relies on clinical echocardiographic reports performed within four weeks prior to the CMR exam. A change in hemodynamics, i.e., pre- and afterload, can impact diastolic dysfunction grading. A desirable approach in the future would be to conduct echocardiography and CMR on the same day and to compare CMR measurements directly to contemporary echocardiographic quantification of diastolic dysfunction, e.g., by transmitral blood flow and Doppler tissue velocity interrogation. Due to varying RR intervals, AF patients can have a different acquisition triggering scheme than the other subgroups. With prospective triggering late diastole is not imaged; however, in patients with AF, this should not impact measurements significantly as there should not be any change in chamber volume and size during this time due to a lack of atrial kick. Additionally, our sample size was small for the subgroup analysis. Further comparisons between software vendors are required due to differences in tracking algorithms and methodological approaches to contour placement.CMR post-processing techniques can assess bi-ventricular and bi-atrial function to monitor atrial dysfunction and myopathy in patients with AF or progressing ventricular diastolic dysfunction. Assessing right and left atrial function with feature tracking or long-axis shortening techniques may allow for early detection of subtle functional abnormalities, even when atrial enlargement is not yet apparent. Our analysis demonstrates that both techniques produce similar results, which indicates that they could potentially be used interchangeably based on the software capabilities of individual sites. Using a CMR-based analysis to understand the individual atrial-ventricular interaction of both the left and right side of the heart in addition to morphology, function, and tissue characteristics allows for a comprehensive interrogation of all four heart chambers. In patients, this could add clinically meaningful information and potentially allow for optimal therapies to be chosen to better target the dysfunction.Supplementary file1 (PDF 396 KB)Below is the link to the electronic supplementary material.


This was not observed in LGE-negative patients. Furthermore, a short T1 time in LGE-positive patients was associated with a higher risk of adverse events (log-rank p = 0.01). Conclusion: This study implies that cardiac biomarkers reflect active remodeling of the non-infarcted myocardium of patients with focal myocardial scarring. Diffuse fibrosis, in contrast to focal scarring, might have a higher prognostic value regarding adverse outcomes in HF patients.Aims: Ongoing adverse remodeling is a hallmark of heart failure (HF), which might be reflected by either focal or diffuse myocardial fibrosis. Therefore, in (pre)clinical settings, we used immunohistochemistry or cardiac magnetic resonance imaging (CMR) to investigate the association of  fibrosis with cardiac biomarkers and adverse events in HF. Methods and results: In C57Bl/6J mice, we determined the presence and extent of myocardial fibrosis 6 weeks post-myocardial infarction (MI). Furthermore, we studied 159 outpatient HF patients who underwent CMR, and determined focal and diffuse fibrosis by late gadolinium enhancement (LGE) and post-contrast T1 time of the non-LGE myocardium, respectively. HF patients were categorized based on the presence of LGE, and by the median post-contrast T1 time. Kaplan–Meier and Cox regression analyses were used to determine the association of fibrosis with HF hospitalization and all-cause mortality. LGE was detected in 61 (38%) patients. Cardiac biomarker levels were comparable between LGE-positive and LGE-negative patients. LGE-positive patients with a short T1 time had elevated levels of both NT-proBNP and galectin-3 (1611 vs. 453 ng/L,  Following acute myocardial infarction (MI), a cascade of cardiac immune cell infiltration, cardiomyocyte necroptosis and formation of granulation tissue contributes to the formation of a focal myocardial scar . AlthougCardiac magnetic resonance (CMR) imaging has evolved as the gold standard noninvasive imaging technique for myocardial tissue characterization. Late gadolinium enhancement (LGE) and T1 mapping techniques allow the determination and quantification of focal myocardial scar formation and detailed tissue characterization including diffuse fibrosis, respectively .In this study, we determined the presence of myocardial fibrosis—either focal myocardial scarring or diffuse fibrosis—and evaluated its relation with cardiac biomarkers and outcomes. For this purpose, we used an MI murine model and a well-characterized cohort of outpatient heart failure (HF) patients, either using immunohistochemistry methods or CMR metrics , respectively.MI was induced in mice with a C57Bl6/J background  by permanent ligation of the left anterior descending coronary artery (LAD). In sham-operated animals, the suture was placed under the artery and removed without ligation. After a follow-up of 6 weeks, mice were sacrificed . In totaMasson’s trichrome staining was performed to determine focal and diffuse myocardial fibrosis in 4 µm paraffin-embedded cardiac tissue sections. Whole stained sections were scanned with a high-throughput scanning system . Focal fibrosis was described as dense and boundless fibrotic patterns replacing the original myocardial tissue structure, as visually detected by an independent researcher. Diffuse fibrosis of the non-infarcted myocardium was defined as interstitial fibrosis evenly distributed between cardiomyocytes, with relatively well-organized myocardial bundles and intact cardiomyocyte morphology or following anatomical structures. Diffuse fibrosis was determined by analyzing all cardiac tissue without evident focal fibrosis. The amount of diffuse fibrosis was quantified as the percentage of positive cells compared to the total scanned area (Aperio ImageScope v12.4.3.5008) and represented as fold change.Total RNA was isolated from snap-frozen left ventricles (LV) using TRI reagent . cDNA synthesis was performed using the QuantiTect Reverse Transcription Kit . A real-time polymerase chain reaction (PCR) was carried out using SYBR Green  using the Bio-Rad CFX384 Real-Time PCR System with associated software . Gene expression was normalized with the mean of 36B4 mRNA content.Consecutive outpatient HF patients who visited the outpatient clinic of the University Medical Center Groningen (UMCG), in Groningen, The Netherlands, between March 2014 and December 2017 were included in this study. Their data were published previously . In totaAll patients were ≥18 years of age and were treated according to the European Society of Cardiology (ESC) guidelines .CMR examinations were performed on a 1.5-T scanner . ECG-gated cine true fast imaging with steady-state free precession (True FISP) sequences with breath holding were performed in three long-axis slices and in contiguous short-axis slices covering the entire LV. The following scan parameters were used: TE 1.1 ms, TR 42 ms, flip angle 55°; matrix 192 × 192, voxel size 1.82 × 1.82 × 8 mm; slice thickness 8 mm; and slice gap 2 mm. Using the short-axis slices, the endo and epicardial borders of the LV were semi-automatically traced and manually adjusted by experienced laboratory technicians using the available software . The LV end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) and mass were calculated using the summation of slices multiplied by slice thickness method.Using identical slice location, LGE images were acquired 10 min after intravenous administration of 0.2 mmol/kg gadolinium-based contrast agent  with a single shot 2D phase sensitive inversion recovery sequence  to identify the location and extent of focal late enhancement. The inversion time was individually set to null the signal of the normal myocardium. The presence of focal LGE was visually determined by one observer (T.M.G.) and reviewed by another observer (T.P.W.). LGE size was quantified with the full width at half maximum technique using QMass 7.6 , and was expressed as a percentage of the total LV mass. The LGE pattern was classified as ischemic  and non-ischemic  based on previous recommendation .Post-contrast T1 measurements were performed using an inversion recovery Look-Locker sequence (True FISP), similar to the T1 scout sequence . The Look-Locker sequence was performed 10 min after the administration of 0.2 mmol/kg gadolinium in a short-axis slice at mid-level over two RR intervals with varying inversion times. The endo- and epicardial borders of the LV were manually traced and adjusted for each image by one observer (T.M.G.) using QMass 7.6 . Special attention was paid to exclude the blood volume. By drawing regions of interest (ROIs) within the endo- and epicardial borders of the LV, and by excluding regions with focal LGE, the post-contrast T1 time of the non-LGE myocardium was determined by fitting the signal intensity to an analytical expression of the T1 inversion recovery :I = A − In Equation (1), the signal intensity (I) is obtained from the average image intensity inside the ROI. The time (t) is the effective inversion time associated with each image. A and B are the scaling and offset constants, respectively. Together with the relaxation time (T1*), they are obtained by nonlinear minimization (fitting) using the Levenberg–Marquardt algorithm. T1 can be obtained from the T1* by performing a correction (Equation (2)) .Galectin-3 levels were measured in EDTA plasma using a chemiluminescent microparticle immunoassay (CMIA) on an Abbott ARCHITECT automated immunoassay analyser . N-terminal B-type natriuretic peptide (NT-proBNP) was measured in Lithium Heparin plasma using a commercially available electrochemiluminescent sandwich immunoassay analyzed on a Roche Modular platform .t-test for normally distributed data, the Mann–Whitney U test for non-normally distributed data and the Spearman’s chi square test for categorical variables. Linear regression analysis was performed to determine the association between diffuse fibrosis and outcome  in mice. Using Kaplan–Meier analysis and a log-rank test, we compared the incidence of the primary composite endpoint of HF hospitalization and all-cause mortality based on the presence or absence of LGE. Subsequently, LGE-positive patients were stratified based upon the median post-contrast T1 time of the non-LGE myocardium. A total of 13 LGE-positive patients were excluded prior to post-contrast T1 time analyses since T1 time measurements were not available. Univariable Cox proportional hazard models were used to evaluate the association between T1 time with the primary endpoint of HF hospitalization and all-cause mortality (per 10 milliseconds decrease in T1 time). All reported p values are two-tailed. A p value < 0.05 suggested statistical significance. All statistical analyses were conducted using STATA software version 16.0  and GraphPad Prism version 9.4.1 .Data are presented as means (±SD) when normally distributed and as medians (interquartile range [IQR]) when non-normally distributed. Categorical variables are presented as number (%). The differences between the two groups were analyzed with the use of the Student’s Lgals3, p = 0.0002), collagen type I alpha I chain  and collagen type III alpha I chain , respectively  and a cluster of differentiation 68   B.p < 0.0001).To determine the presence and extent of diffuse myocardial fibrosis after a MI, the amount of fibrosis was quantified in the non-infarcted area of the myocardium A. At 6 wp < 0.0001; To assess the relation of diffuse myocardial fibrosis with HF severity, we performed linear regression analyses between diffuse fibrosis, as assessed by Masson’s trichrome staining, and LVEF. Diffuse fibrosis was shown to be associated with LVEF  and showed a higher incidence of coronary artery disease at baseline (52% vs. 8% p < 0.001), but no differences in LVEF, cardiac biomarker levels or the severity of HF symptoms—determined by NYHA class—could be observed.To study focal myocardial fibrosis and cardiac biomarkers, patients were categorized based on the presence or absence of LGE. In total, 98 patients (62%) could be classified as LGE negative and 61 patients (38%) as LGE positive. LGE-positive patients were more often male . For the patient selection flow chart, see n = 18, 75% in both) of patients showed a subendocardial or transmural LGE pattern, reflecting myocardial ischemia. Patients with shorter post-contrast T1 time showed higher levels of both NT-proBNP  and galectin-3   , Table 2p = 0.69).During a median follow-up of 2.6 [2.1–3.1] years, 10 (16%) patients experienced death and 10 (16%) were hospitalized for HF, compared to 12 (12%) and 11 (11%) of the LGE-negative patients. In total, 15 (25%) LGE-positive patients experienced the primary composite outcome compared to 20 (20%) of the LGE-negative patients. Using Kaplan–Meier analysis, no difference in event-free survival was observed between LGE-positive and LGE-negative patients  rather than death of any cause (log-rank p = 0.16). In univariable Cox regression analyses, patients with a shorter T1 time showed a higher risk of HF hospitalization and all-cause mortality . Due to a small number of events, no multivariable regression analysis was performed.In LGE-positive patients, HF hospitalization and all-cause mortality were reached in 9 (43%) patients with a shorter post-contrast T1 time, compared to 3 (14%) patients with a longer T1 time during follow-up. Those patients with a shorter post-contrast T1 time had a worse prognosis regarding HF hospitalizations and all-cause mortality compared to those with a longer T1 time (log-rank p = 0.24) could be observed.As a sensitivity analysis, post-contrast T1 time was also determined in LGE-negative patients. LGE-negative patients were stratified according to the median of the post-contrast T1 time (median T1 time 405 [372–436] ms). In LGE-negative patients, hospitalization for HF and death occurred in 8 (18%) of the patients with a shorter post-contrast T1 time and in 11 (25%) of the patients with a longer post-contrast T1 time. No association with cardiac biomarker levels nor prognosis (log-rank Our results indicate that diffuse fibrosis (1) is evident in the non-infarcted area of the myocardium, (2) is associated with biomarkers of cardiac stretch and remodeling, and (3) has higher prognostic value regarding adverse outcomes compared to focal fibrosis in outpatient HF patients with evident myocardial scarring .First, we show that diffuse fibrosis develops through the entire non-infarcted myocardium, alongside evident focal scarring, as a response to tissue damage after MI in mice. On the cardiac gene expression level, fibrosis is also evident, as depicted by a 5-fold increase in expression of galectin-3. Regarding outcome, diffuse fibrosis shows a strong association with cardiac function, as reflected by LVEF. Over the past decade, it is becoming increasingly clear that myocardial fibrosis plays a major role in the pathophysiology of CV disease . DiffuseLGE is known for its diagnostic accuracy in the assessment of focal scar formation and has high prognostic value, especially concerning sudden cardiac death and (life-threatening) ventricular arrhythmias ,22. HoweIn this study, diffuse myocardial fibrosis was assessed with a post-contrast T1 time of the non-infarcted myocardium and predicted prognosis. While 14% of patients with long T1 time were readmitted for HF or died of any cause, this concerned 43% of the patients with a short T1 time. This is in line with several studies emphasizing the prognostic importance of interstitial fibrosis in non-ischemic cardiomyopathy ,24, and Previous human studies have shown the high accuracy of T1-based metrics  in discriminating healthy from fibrotic cardiac tissue, and are associated with the presence and extent of diffuse fibrosis determined by cardiac biopsy and after autopsy . HoweverPreclinical studies and clinical trials targeting cardiac fibrogenesis are emerging ,29,30. IDespite ample evidence on the beneficial effects of targeting diffuse fibrosis, translation to clinical practice has not been accomplished yet. The difficulty of determining a robust study endpoint is probably one of the major reasons, since this usually entails invasive processes  or may not fully reflect cardiac remodeling  . Based oTogether, our findings indicate that diffuse cardiac fibrosis plays an important role in active remodeling of the non-infarcted myocardium of patients with focal myocardial scarring. CMR-assessed diffuse fibrosis could provide an accessible and powerful noninvasive tool to determine prognosis in outpatient HF patients, and could potentially be used to determine the effectiveness of anti-fibrotic medication.A few limitations should be acknowledged. First, this study includes only a limited number of outpatient HF patients, preventing us from multivariable-adjusted analyses; as a result, conclusions should be drawn with some restraint. Second, the relationship of diffuse fibrosis with cardiac biomarkers and the prognostic value of this relationship regarding outcome were only observed in HF patients with focal myocardial scarring on CMR. In line with this, the majority of LGE-positive patients showed an ischemic LGE pattern. However, the LGE pattern of some patients was considered non-ischemic. The role of diffuse fibrosis and its usefulness regarding prognosis might differ between different HF etiologies, for instance, between ischemic and non-ischemic HF patients.Because of the retrospective nature of this study, it was not possible to determine the relation and prognostic value of other (cardiac) biomarkers, for instance soluble ST2 and growth differentiation factor-15 (GDF-15), both known to be involved in inflammation and fibrosis.Additionally, T1-based indices may be affected by other pathological processes , and are highly dependent on CMR equipment and the time between contrast agent administration and measurements. Therefore, it is difficult to directly compare (post-contrast) T1 times between different studies and hospitals. Additionally, in this study, only post-contrast T1 time was determined, while ECV is increasingly being used to differentiate cardiomyopathy etiology. It would have been interesting to compare prognostic performance of different CMR metrics.When using CMR as a robust study endpoint for diffuse fibrosis, it is worth considering the cost-effectiveness of CMR, especially in healthy subjects. Since the average price of CMR is EUR 160 to 1400 per scan , the cos