We characterized the dynamics of eosinophils in blood and in the infarcted myocardium in patients and in a swine model of reperfused myocardial infarction (MI). The association of eosinophil dynamics with various outcomes was assessed.Serial eosinophil count and pre-discharge cardiac magnetic resonance were carried out in a prospective series of 620 patients with a first ST-elevation MI. In a swine model of reperfused MI, the dynamics of circulating eosinophils and their presence in the infarcted myocardium were determined. In autopsies from chronic MI patients, eosinophils were quantified.Patient eosinophil count sharply decreased 12h post-reperfusion compared to arrival. A lower minimum eosinophil count was associated with more extensive edema, microvascular obstruction, and infarct size as measured by cardiac magnetic resonance, and also with a higher rate of cardiac events  during follow-up. In the experimental model, eosinophil count boosted during ischemia and dropped back immediately post-reperfusion. Myocardial samples revealed progressive eosinophil migration into the infarcted myocardium, especially areas with microvascular obstruction. Markers of eosinophil maturation and survival (interleukin-5), degranulation (eosinophil cationic protein) and migration (eotoxin-1) were detected in the blood of patients, and in porcine myocardium. Eosinophil infiltration was detected in autopsies from chronic MI patients.Eosinopenia post-MI was associated with an impaired cardiac structure and adverse events. The decay in circulating eosinophils soon after reperfusion mirrors their migration into the infarcted myocardium, as reflected by their presence in heart samples from swine and patients. Further studies are needed to understanding this unexplored pathway and its therapeutic implications. Eosinophils are granulocytic leukocytes that play an essential role in allergic reactions, asthma, and parasitic infections. Although eosinophils normally account for only 1–3% of circulating leukocytes, the number of both peripheral and tissue eosinophils are markedly altered in some inflammatory reactions . FollowiIn ST-segment elevation myocardial infarction (STEMI), the occurrence of an acute deregulation of the immune system, and its association with the resultant structural myocardial damage and patient outcome has been solidly demonstrated. Indeed, the role of fluctuations in neutrophil and monocyte cell counts and, more recently, in lymphocyte subsets  have been widely addressed in this scenario –8.The deleterious effects of eosinophils in other cardiovascular diseases such as eosinophilic myocarditis are well established ,9. PreliTo investigate the association between eosinophils  and outcomes, we focused on the following specific objectives: 1) To analyse serial eosinophil cell count in peripheral blood of reperfused STEMI patients and determine its association with cardiac magnetic resonance (CMR)-derived edema, microvascular obstruction (MVO), and infarct size as well as with the occurrence of major adverse cardiac events (MACE) during follow-up. 2) To determine serial eosinophil cell count in blood obtained from the coronary sinus and to quantify eosinophil cell infiltration into the infarcted myocardium and in areas with MVO in myocardial samples obtained from a swine model of reperfused MI. 3) To scrutinize the temporal evolution in blood (in patients) and in the infarcted myocardium (in swine) of crucial molecules implicated in eosinophil production, maturation, and recruitment. 4) To quantify the presence of eosinophils in myocardial samples obtained from autopsies of chronic MI patients.Patient samples were acquired with appropriate ethical permission from the Hospital Clinico Universitario de Valencia´s Ethics Committee. All procedures involving animals were approved by the University of Valencia’s Animal Ethics Committee (2016/VSC/PEA/00074).The study protocol complies with the 1975 Declaration of Helsinki guidelines. All participating patients provided written informed consent.We prospectively included 691 consecutive patients admitted to a university hospital for a first STEMI between 2004 and 2016 treated with primary coronary intervention and undergoing pre-discharge CMR. Inclusion criteria were stable clinical course during admission, no contraindication to CMR, and no condition related to an alteration of the immune system apart from the MI index.We excluded 71 patients for the following: death (n = 16), re-infarction (n = 8), severe clinical instability precluding CMR (n = 18), claustrophobia (n = 5), cardiac surgery (n = 3), infections (n = 12), corticoids treatment (n = 7), and leukemia (n = 2). The final study group comprised 620 patients .Patients included in the study group were examined with a 1.5 T System  7±2 days after STEMI in accordance with our previously validated study protocol ,16. CMR 2), LV end-systolic volume index (ml/m2), and LV mass index (g/m2) were determined in cine images. As proxies of the magnitude of structural myocardial damage, the extension of myocardial edema (% of LV mass), infarct size (% of LV mass), and MVO (% of LV mass) were quantified. Myocardial edema was regarded as areas of high T2 signal intensity. All short-axis view slices were separately analysed and the presence of edema was visually quantified by manual planimetry and expressed as percentage of LV mass.Left ventricular (LV) ejection fraction (%), LV end-diastolic volume index (ml/mInfarct size (% of LV mass) was assessed as the percentage of LV mass showing late gadolinium enhancement. Microvascular obstruction  was quantified by manual planimetry and defined as the percentage of LV mass showing a lack of contrast uptake in the tissue core showing late gadolinium enhancement –17.Based on previously validated data –17, the MACE consisted of cardiac death, admission for nonfatal re-infarction, or for heart failure, whichever occurred first. Current definitions were applied ,19. MACETotal leukocyte counts, and eosinophil counts  were measured upon patient arrival, and at 12, 24, 48, 72, and 96 hours after revascularization by an automated blood cell counter. Patient serum was obtained by centrifuging blood samples at 2500 rpm for 15 min, and immediately stored at -80°C until further analysis .Serial serum samples obtained from STEMI patients were assayed for eosinophil cationic protein (ECP), for interleukin (IL)-5, and for eotaxin-1.The experimental study conforms to the guide for the care and use of laboratory animals published by the US National Institutes of Health . Our study protocol has been previously validated  and furtSus scrofa) weighing 25–30 kg were employed. During the surgery protocol, animals were mechanically ventilated employing 50% oxygen gas mixture, and the heart rate, rhythm, and ST-segment changes were continuously monitored.Domestic female pigs  no-reperfusion, 2) 1-minute, 3) 3-days, 4) 7-days, and 4) 1-month reperfusion (n = 5 each). The control group (n = 5) was subjected to the same experimental protocol used in the MI groups, but without angioplasty balloon inflation, thus ischemia and infarction were not induced.Further information about macroscopic determination of MVO and infarct size as well as blood sampling is specified in +CD16- cells.FITC-CD45 and PE-CD16 conjugated antibodies  were used to quantify eosinophils in whole blood samples obtained throughout the experimental studies. Eosinophils were gated as CD45Samples were analysed using a BD FACSVerse flow cytometer , and a minimum of 10,000 events was acquired. FlowJo 8.7 software was applied for the analysis of all the acquired data.The mRNA expression of eosinophil-specific genes (eosinophil peroxidase (EPO), IL-5, and eotaxin-1) was assessed in myocardial samples obtained from the infarcted and remote areas in the six experimental groups.Experimental myocardial samples were fixed, embedded in paraffin, sectioned and mounted on glass slides. Hematoxylin-eosin stain  was performed for histological analysis. Collagen deposition was detected using picrosirius red staining . Luna’s Myocardial samples of three patients with a chronic infarct (more than 6 months after acute MI), and three control subjects were obtained from autopsies.Presence of eosinophils was histologically evaluated following the same protocol described for the experimental samples .Data were tested for normal distribution using the Kolmogorov-Smirnov test. Continuous normally distributed data were expressed as the mean ± the standard deviation of the mean and compared using the unpaired Student’s t-test or one-way ANOVA. Non-parametric data were expressed as the median with the interquartile range and compared using the Mann-Whitney U-test or Kruskal-Wallis. Group percentages were compared using the Chi-square test or Fisher’s exact test where appropriate. Linear correlations were assessed using the Pearson’s correlation coefficient. The association of eosinophil minimum count  with time to first MACE was determined by the respective Kaplan-Meier curve and the log-rank test. Statistical significance was considered for two-tailed p-value <0.05. All statistical tests were performed using SPSS 19.0 .The baseline and CMR characteristics of the 620 patients included in the final study are shown in The characteristics of patients with and without CMR-derived extensive edema, MVO, and infarct size are shown in During follow-up , 125 MACE  occurred. Baseline characteristics and CMR parameters related to MACE are displayed in +CD16- cells  that reached its maximum value soon (30 min) after reperfusion. Later (7 days and 1 month after reperfusion), eosinophil count dropped to baseline values .These results reveal events in a period not accessible for studies in patients and suggest that the fall in circulating eosinophils detected in STEMI patients 12h after coronary reperfusion seems to be preceded by a boost in the number of eosinophils during ischemia and immediately after reperfusion .In comparison to controls, histological and morphometric analysis of the infarcted myocardium isolated from the experimental model revealed infiltration of eosinophils at 3 days, 7 days, and 1 month post-reperfusion . EosinopA weak gene expression of EPO (an eosinophil-specific protein) occurred in myocardial samples obtained from controls and from the infarcted area of the non-reperfusion and 1-min reperfusion groups. In contrast, a significant up-regulation of EPO was detected in myocardial samples obtained from the infarcted area of the 3-day, 7-day, and 1-month reperfusion groups . NeitherIn summary, the rapid increase in circulating eosinophils after ischemia onset detected in the experimental model is followed by a marked fall after reperfusion, both in the experimental and clinical models. Migration of eosinophils into the infarcted myocardium might explain the massive loss of circulating eosinophils.To explore the association between the infiltration of eosinophils in the infarcted myocardium following reperfusion and the occurrence of MVO, we carried out 2 studies.Firstly, we analysed the extension of MVO in all experiments with macroscopic evidence of infarction. Two groups were defined: experiments with extensive , and without extensive MVO. Eosinophil infiltration in the infarct area was significantly higher in experiments classified as extensive MVO . RepreseP<0.05 vs. non-extensive MVO.Images were quantified with Image-Pro Plus analysis software. Data  were analysed by Student’s t test. Scoring was performed by a blinded observer unaware of the experimental group. *Secondly, in the same experiments used for the previous analysis, each heart was individually evaluated and the magnitude of eosinophilic infiltration in samples obtained from the infarcted areas with macroscopic MVO was morphometrically quantified and compared with those infarcted areas without macroscopic MVO. Of note, eosinophil infiltration was significantly higher in infarcted areas with MVO compared with infarcted areas without MVO . RepreseTherefore, after reperfused MI, eosinophils infiltrate into the infarcted myocardium, and accumulate mainly in areas with MVO. This might in part explain the more extensive CMR-derived myocardial structural damage  and the higher risk of cardiac events detected in STEMI patients with more severe eosinopenia following reperfusion.To investigate the temporal changes in serum levels of IL-5 , ECP (a cytotoxic molecule secreted after eosinophil activation), and eotaxin-1 (that selectively drives eosinophil recruitment into the damaged area) , we perfIn STEMI patients, soluble IL-5 was persistently elevated from arrival (before reperfusion) and throughout the first month after MI .In swine, a weak mRNA expression of IL-5 gene occurred in controls and in the infarcted area of the no-reperfusion and 1-min reperfusion groups. Interestingly, a significant up-regulation of IL-5 was detected in myocardial samples obtained from the infarcted area 3 days, 7 days, and 1 month after reperfusion . Indeed,In STEMI patients, circulating ECP was significantly elevated upon arrival (before reperfusion), peaking at 24h and 96h, and returning to values similar to control subjects 1 month after infarction . These rCirculating eotaxin-1 levels, a potent eosinophil chemoattractant, were significantly higher in control subjects than in STEMI patients. Indeed, no significant dynamic changes where observed in STEMI patients at different time-points of the ischemia-reperfusion process .In porcine hearts, the gene expression of eotaxin-1 was weak in controls and in the infarcted area of the no-reperfusion and 1-minute reperfusion groups. On the contrary, a marked increase in its expression occurred in the 3-day, 7-day, and 1-month reperfusion groups . MoreoveAdditionally, the augmented presence of eotaxin-1 in the infarcted tissue was also corroborated by immunohistochemistry . EotaxinThe presence of eosinophils was also determined in myocardial samples of patients with chronic infarction. Clinical and autopsy characteristics of patients included in the study group are displayed in We undertook the present study in a large series of STEMI patients and in a highly controlled swine model of MI to gain knowledge on the dynamics, implications, and regulation of eosinophils in the setting of acute reperfused MI .A highly controlled and orchestrated immune response is a necessary step for an adequate repair of the infarcted area. In contrast, an excessive and deregulated activation of the inflammatory cascade has been solidly demonstrated to mediate unnecessary myocardial damage and in turn associates with worse clinical outcomes in STEMI patients ,6. PeripIn our study, the association of these dynamics with the resulting myocardial structural damage was evaluated in 620 STEMI patients using the current gold standard non-invasive imaging technique, namely CMR. The occurrence of MACE was monitored during a 90-week median follow-up. Overall eosinophil count dramatically dropped soon after revascularization, observing the more severe the fall, the more extensive the structural myocardial damage in terms of CMR-derived edema, MVO, and infarct size. Unsurprisingly, and in view of the association of post-reperfusion eosinopenia with the magnitude of these potent prognostic parameters, a sharp loss of circulating eosinophils within the first hours after reperfusion was also related to a higher MACE rate in STEMI patients during follow-up.In line with our results, some studies have reported that a lower eosinophil cell count is associated with a higher risk of cardiac events after MI –12. For Although this finding could be incorporated into our daily armamentarium to improve early risk stratification of STEMI patients, this was not the objective of our research since widely validated scores and recommendations already very well achieve this goal. In our view the ultimate interest of the observations obtained in our clinical series lies in turning attention to the need of a deeper understanding of the true dynamics and regulation  of eosinophils from MI onset. For this purpose and in parallel with the clinical research we investigated the course of eosinophils as well as of crucial products and regulators of these cells in a swine model of reperfused MI.The design of clinical studies in MI implies that analyses begin after the first medical contact or more commonly upon patient arrival at the emergency room. This prevents investigation of the dynamics of crucial players in the pathophysiology of MI, in this case inflammatory cells, at the very moment of coronary occlusion and MI onset. For this purpose we used our previously validated porcine model of MI  that allUsing the same approach, our group has recently reported that circulating lymphocyte count exhibits a similar pattern as that shown in the case of eosinophils: a rapid proliferation during ischemia and immediately post-reperfusion, followed by a sharp decline afterwards . ResearcAccording to our results, eosinophil cell count boost after MI onset is followed by severe decay in peripheral circulation in the hours after coronary revascularization. The mechanisms underlying this sequence are not yet fully understood. Involvement in coronary thrombi formation  might inIn 1978, Fishbein and coworkers first demonstrated the presence of eosinophils in the infarcted myocardium . Since tWe histologically detected the presence of eosinophils in the infarcted area soon  and late (1 month) after reperfusion in experimental samples. These cells persisted in myocardial samples obtained from patients late (>6 months) after MI. Migration of eosinophils into injured tissues has been described in many pathological situations, where they undergo degranulation, exert pro-coagulant and toxic effects, and modulate the immune response through different mechanisms .Interestingly, eosinophil infiltration was more intense in areas with the most severe structural damage, namely with MVO. This is a multifactorial process characterized by microvascular disruption leading to severe myocardial structural damage. Not surprisingly this phenomenon exerts deleterious effects on LV remodelling and on patient outcomes. The mechanisms underlying microvascular damage in reperfused MI are far from being completely understood . NeutropTo further clarify the dynamics of eosinophils in this setting, we sequentially determined crucial proteins related to their maturation, activation and recruitment, both in peripheral blood and in myocardial samples.Eosinophils are granulocytic leukocytes actively involved in numerous inflammatory processes ,4. InfilECP, a marker of eosinophil activity, is released by cell degranulation and participates in the activation of the coagulation cascade. It has been previously reported that ECP can increase in the whole spectrum of stable and unstable ischemic heart disease ,28. In SEotaxin-1 is a potent eosinophil-specific chemoattractant that has been related, not only to eosinophil recruitment, but also to vascular inflammation  and has Finally, involvement of IL-5 has been demonstrated in eosinophil differentiation, activation and survival, both in peripheral blood and in tissue ,2. SerumThe present study demonstrates the participation of eosinophils and their products in the pathophysiology of reperfused MI and their association with the magnitude of the myocardial structural damage and the clinical course of patients. The causal role of eosinophils in these associations and the potential therapeutic interventions that could be derived need to be addressed in future studies.Furthermore, since some differences in eosinophil physiology between humans and swine may exist, further clinical investigation might be carried out in order to continue elucidating the role of eosinophils after MI.Certain bias towards the exclusion of patients with severe clinical condition might occur.In the setting of reperfused MI, eosinophils exhibit important dynamic changes, both in peripheral blood and in the infarcted area. Peripheral eosinophilic cells display a rapid activation immediately after coronary occlusion, followed by a massive loss soon after reperfusion. This sequence induces massive eosinopenia, that in STEMI patients is associated with more severe structural myocardial damage and higher risk of cardiac events. Simultaneously, release of potent mediators induces sustained eosinophil proliferation, activation, and migration into the infarcted area. Finally, the acute peripheral cell count decay appears to be mediated by myocardial infiltration that takes place mainly in zones with the most severe structural damage, namely with MVO, and persists in chronic phases.The presented results strongly suggest the need for further studies to better understand the pathophysiological role of this almost unexplored pathway as well as the potential therapeutic implications that could be subsequently explored.S1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOCX)Click here for additional data file.S4 Table(DOCX)Click here for additional data file.S5 Table(DOCX)Click here for additional data file.S6 Table(DOCX)Click here for additional data file.S7 Table(DOCX)Click here for additional data file.S1 FigThis flow chart shows the ST-elevation myocardial infarction (STEMI)-patients recruitment (A) and blood sampling (B). MR: magnetic resonance; PCI: primary coronary intervention.(TIF)Click here for additional data file.S2 FigSamples were incubated with FITC-CD45 and PE-CD16 and afterwards measured using flow cytometry. Eosinophils were identified from the rest of leukocytes as CD45+CD16- cells (left panel). Representative histograms from basal  and 30-min post-reperfusion (right panel) samples were displayed.(TIFF)Click here for additional data file.S3 Fig(A) Representative images from infarcted tissue isolated from control and two MI groups (90-min of ischemia followed by no reperfusion and 1-min reperfusion) stained with hematoxylin-eosin (HE) (upper panel). The presence of eosinophils was revealed by staining myocardial samples with Luna’s technique, specific for eosinophil granules (lower panel). (B) The expression of eosinophil peroxidase (EPO) in the infarcted myocardium at different times of the ischemia and reperfusion process. Data  were analysed by one-way ANOVA analysis followed by Bonferroni test.(TIF)Click here for additional data file.S4 Fig(A) Representative images from infarcted tissue isolated from control and five MI groups  stained with hematoxylin-eosin (HE) (upper panel). The presence of eosinophils was revealed by staining myocardial samples with Luna’s technique, specific for eosinophil granules (upper panel). (B) The expression of eosinophil peroxidase (EPO) in the remote myocardium at different times of the ischemia and reperfusion process. Data  were analysed by one-way ANOVA analysis followed by Bonferroni test.(TIF)Click here for additional data file.S5 FigRepresentative images of eosinophil infiltration in hearts with (A) extensive and without extensive microvascular obstruction (MVO) and in myocardial regions with (B) MVO and without MVO.(TIFF)Click here for additional data file.S6 FigECP: eosinophil cationic protein; EMBP: eosinophil major basic protein; EPO: eosinophil peroxidase; IL: interleukin.(TIFF)Click here for additional data file.S7 Fig(TIFF)Click here for additional data file.S8 FigCMR: cardiac magnetic resonance; MACE: major adverse cardiac events; MI: myocardial infarction; MVO: microvascular obstruction; STEMI: ST-segment elevation myocardial infarction.(TIFF)Click here for additional data file.S9 FigMyocardial tissue was stained with thioflavin-S (left panel) and light blue area represents the area at risk. Illustrative images of heart slices stained with 2,3,5-triphenyltetrazolium chloride solution (right panel).(TIFF)Click here for additional data file.S1 File(DOCX)Click here for additional data file.


The measurement of native T1 through cardiovascular magnetic resonance (CMR) is a noninvasive method of assessing myocardial fibrosis without gadolinium contrast. No studies so far have evaluated native T1 after renal transplantation. The primary aim of the current study is to assess changes in the myocardium native T1 6 months after renal transplantation.We prospectively evaluated 44 renal transplant patients with 3 T CMR exams: baseline at the beginning of transplantation and at 6 months after transplantation.p = 0.001). The patients were split into two groups through a two-step cluster algorithm: In cluster-1 (n = 30) the left ventricular (LV) mass index and the prevalence of diabetes were lower. In cluster-2 (n = 14) the LV mass index and diabetes prevalence were higher. Decrease in native T1 values was significant only in the patients in cluster-1 (p = 0.001).The native T1 time was measured in the midventricular septum and decreased significantly from 1331 ± 52 ms at the baseline to 1298 ± 42 ms 6 months after transplantation  contains supplementary material, which is available to authorized users. Patients with chronic kidney disease (CKD) are at increased risk for cardiovascular disease (CVD) , 2. RenaThree types of myocardial fibrosis have been reported: reactive interstitial fibrosis, infiltrative interstitial fibrosis and replacement fibrosis , 10. FibMyocardial fibrosis is confirmed with endomyocardial biopsy, but it is a procedure with high morbidity , 15. ImaAs an alternative, myocardium native T1 mapping is a resonance method that evaluates myocardial and quantify the fibrosis without the use of gadolinium contrast , 20. TheIt has already been demonstrated that in the hemodialysis population, native T1 values are higher in comparison with healthy subjects . HoweverThe primary aim of this study was to evaluate the changing of septal native T1 between baseline and 6 months after renal transplantation.This prospective single-center cohort study was performed in a tertiary medical center . A total of 44 patients underwent two CMR examinations. The first exam (baseline) was performed between the 1st and the 10th postoperative days. The second one was performed 6 months after renal transplantation. Changes in the native T1 were evaluated by comparing the first and second exams of the same patient. The protocol was reviewed and approved by the institutional review board (CAAE: 40598414.9.0000.5411). Written informed consent was obtained from the subjects before participation.We included consecutive patients over 18 years of age who received a renal transplant from a living or deceased donor. We excluded patients with a contraindication to CMR  and inability to perform breath hold.All examinations were performed on the same 3 T CMR system  with a phased array chest coil, according to study protocol. A cardiac cine balanced steady-state free precession (bSSFP) sequence was acquired using retrospective cardiac gating. Typically, 25 phases were acquired in 2-, 3-, and 4-chamber long axis views and a stack of short axis views. Scan parameters: field of view (FOV) 37-cm, repetition time 43.54 ms, echo time 1.38 ms, flip angle 50°, slice thickness 6 mm, in-plane image resolution 1.6 × 1.6 mm. Quantitative T1 mapping was performed with a Modified Look-Locker Inversion-Recovery (MOLLI) sequence in mid-cavity short axis slice, without gadolinium (Native T1) following the recommendations of the European Society of Cardiology consensus . Scan paBiventricular ejection fraction, volumes and LV mass were calculated from the short-axis cine images with post-processing using Argus software . Endocardial contours were drawn at both end-diastole and end-systole. LV epicardial contours were drawn only at end-diastole to calculate LV mass. This technique was repeated for each short-axis slice and the software calculated the volumes, mass and ejection fraction using the Simpson method. T1 maps were automatically generated on the CMR scanner. A region of interest (ROI) was then drawn in the septal myocardium to obtain T1 value . The plots were built with R  version 3.4.2 with the ggplot2 package.A cluster analysis was conducted using the two-step cluster analysis algorithm with the Schwarz Bayesian criterion for clustering. The number of clusters by automatic selection and the distance were measured with log probability. The TwoStep Cluster Analysis procedure is an exploratory tool designed to reveal natural groupings within a dataset that would otherwise not be apparent. This was used in this study to group the baseline clinical variables into strongly interrelated subgroups (clusters) without prior knowledge of the target variables. We used all baseline clinical variables to build the cluster analysis that automatically resulted in two clusters. This analysis creates groups that are more similar to each other based on the log probability distances . The median time from transplant to the first exam was 5 days and to second exam was 189. The hematocrit was similar for the first CMR exam and preoperative value (mean difference − 0.9% [95%CI -1.437 to 3.237] p = 0.44). The baseline donor and recipient characteristics are detailed in Table There were 44 patients who completed the two CMR evaluations   there were no patients with diabetes mellitus and in cluster-2 (n = 14), all 14 patients (100%) had diabetes  than in cluster-1 .The 44 patients were divided into 2 groups by two-step cluster algorithm. In cluster-1 (2 (baseline) to 81.5 ± 14.1 g/m2 . In cluster-2, the LV mass index did not change (93 ± 21.1 g/m2 (baseline) to 92.2 ± 17.2 g/m2 .  to 68.6 ± 12.2% (6 months), p = 0.09.The LV ejection fraction (EF) changed from 64.1 ± 13.5% (baseline) to 66.3 ± 8.5% (6 months) in cluster-1, p = 0.001). In cluster-2, the native T1 was similar at baseline and at 6 months  to 1293 ± 38.7 ms  and angiotensin II receptor blockers (ARBs), reduces myocardial fibrosis, regardless of its hypotensive action . In addiWe found that at 6 months after renal transplantation, heart rate and systolic and diastolic blood pressures decreased significantly. This finding probably resulted from inactivation of the sympathetic system and the renin-angiotensin-aldosterone system after transplantation. Both systems, when activated, stimulate intracellular signaling pathways, with consequent increase in protein synthesis in myocytes and fibroblasts leading to cellular hypertrophy and fibrosis . Other eIn the CMR evaluation, considering ventricular function, volume and mass, we did not find differences at 6 months, similar to Patel  and PrasIn contrast, improved CMR derived LV parameters have been demonstrated in children within 6 months after transplantation , indicatIn a different way from the ventricular function and mass, the native T1 was significantly reduced 6 months after renal transplantation. The native T1 time is a sensitive marker of myocardial fibrosis , 37–39 aTo date, no prior studies have evaluated native T1 in renal transplant recipients. Using 3 T CMR and measuring T1 times in the midventricular septum, Rutherford and Graham-Brown et al. found lower native T1 values in hemodialysis patients than the baseline values of the present study , 38. An The discrepancies between ventricular mass/function and fibrosis in the present study are related to the specificity of the method. Thus, the studies that demonstrated a reduction of ventricular mass in post-transplant were performed using transthoracic echocardiography, which may be influenced by volume overload . FurtherIn order to explore hidden patterns in the data, we performed a cluster analysis, and a group showed no improvement of native T1. The main finding of this group was the greater rate of diabetes. Previous studies have demonstrated that high glucose concentrations can lead to pathological changes in the myocardium, including the accumulation of ECM proteins. Mechanisms responsible for these alterations may include overproduction, decreased degradation, and / or chemical modifications of ECM proteins . ConsequAlthough native T1 time has demonstrated a positive correlation with biopsy-proven fibrosis in diseases with pressure overload , we coulIn conclusion, myocardial native T1 decreased significantly 6 months after renal transplantation. Patients that do not achieve a significant decrease in native T1 include those with diabetes and those with highest baseline LV mass index. The measurement of native T1 time by CMR may be considered an appropriate complementary method to evaluate myocardial fibrosis in renal transplant patients without using contrast.Additional file 1:Statistical analysis of Two-Step Cluster. Cluster sizes and importance of the predictors. (DOCX 38 kb)Additional file 2:n = 44 before and n = 44, 6 months after transplantation). (TIFF 439 kb)Analysis of individual cases of native T1 map at baseline and 6 months after transplantation  at baseline and 6 months after transplantation. B: Analysis of individual cases of LVMi at baseline and 6 months after transplantation. C: Boxplot comparing Left Ventricular Mass index (LVMi) at baseline and 6 months after transplantation split into two groups (clusters). D: Analysis of individual cases of native T1 map at baseline and 6 months after transplantation splitted into two groups by Cluster analysis. (TIF 1406 kb)Additional file 4:n = 44 before and n = 44, 6 months after transplantation). (TIFF 268 kb)Analysis of individual cases of native T1 map at baseline and 6 months after transplantation splitted into two groups by Cluster analysis.


Septal myectomy is currently the gold standard treatment for symptomatic patients with hypertrophic cardiomyopathy. The procedure needs to be tailored and performed in a personalized fashion, taking into consideration the anatomical spectrum of this disease. The procedure needs to address the various components that contribute to the clinical and pathological picture of this disease including, the fibrous trigones, accessory tissues, papillary muscles, mitral valve and myocardial bridges. The operation can be performed with very low mortality and morbidity in high-volume experienced centers with predictable excellent short and long-term outcomes. There is a need for broadening the experience of this procedure to the rest of the world and for future development of new enhanced precision imaging and surgical tools. Septal myectomy remains the gold standard therapy for HCM patients who are symptomatic with high LVOT gradients3. The results of this procedure have vastly improved over time and it is now performed with low mortality and morbidity in experienced surigical centers. The results of this operation depend on thorough understanding of the sophisticated function of the LVOT and its derangements in HCM. We here describe the functional and surgical pathology of the left ventricular outflow tract (LVOT), followed by the key elements of the restorative tailored operation.Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disorder with a prevalence of 1:500 in the adult general population. LVOT obstruction is a common feature of the disease and plays an important role in the clinical outcome, both in terms of symptoms and longevity1,4,5. The LVOT shares the same orifice with the mitral valve (The aortic root and left ventricular outflow tract (LVOT ) occupy a central location in the heart and connect it to the rest of the arterial systemal valve . The aorAbnormalities of the left fibrous trigone are more common in HCM patients than those of the right. The fusion of the left fibrous trigone prevents the subaortic curtain from moving backwards during systole and contribute significantly to systolic anterior motion (SAM) of the mitral valve and LVOT obstruction.6,7.The mitral valve contributes to subaortic obstruction in patients with HCM via systolic anterior motion. The structural abnormalities of the mitral valve in HCM are seen prior to the development of septal hypertrophy or flow acceleration in the LVOT. SAM is produced by the paradoxical movement of the anterior leaflet of the mitral valve, or occasionally by the posterior leaflet (PAM), toward the septum that produce pressure gradient across the LVOT and induce mitral valve regurgitation  and 36,7SAM was thought to be caused by Venturi effect that results in a suction effect of the mitral valve toward the ventricular septum. Another mechanism of SAM is due to elongated leaflets or displaced papillary muscles altering the coaptation point between the anterior and posterior leaflet of the mitral valve. This situation creates a residual portion of the anterior leaflet which will be pushed by the ejection of blood during systole. This explains why obstructive SAM can accompany modest septal hypertrophy when excessive or segmental leaflet elongation and papillary muscle malposition is present. This mechanism is important to understand and to be addressed to prevent the persistentance of SAM after surgical myectomy. Mitral valve abnormalities that need to be addressed surgically while performing myectomy include: (a)Abnormal chordae attaching the mitral valve or the papillary muscles to the septum or free ventricular wall. (b)Fusion of the anterolateral papillary muscle to the free ventricular wall. (c)Coexistence of organic disease in the mitral valve causing flail segments of one or both mitral leaflets.8:There is a spectrum of abnormal papillary muscle attachments or muscle bundles seen in HCM, which can be divided into four types (a)Anomalous muscle bundles between the interventricular septum (IVS) and ventricular apex, anterior papillary muscle (APM), or posterior papillary muscle (PPM) (b)APM or PPM adhesion to the IVS and left ventricular wall (c)Accessory muscles that originated from the APM, PPM or IVS that insert directly into leaflets (d)Anomalous chords attached to IVS.9,10. This can be easily diagnosed by pre-operative selective coronary angiography or cardiac CT scan. Myocardial bridging is often a benign condition, however, some reports have suggested a distinct association between myocardial bridging and more severe symptoms, ventricular arrhythmias, and sudden death in children with HCM. This is explained by the fact that myocardial bridges will result in coronary microvascular compromise. This will result in reverse remodeling, that may precipitate malignant arrythmia and progress to myocardial fibrosis. The adrenergic drive enhances systolic compression of the tunneled LAD artery to a sufficient degree to disturb blood flow. This is not limited to the systolic phase, but also extends into the diastolic phase, which is critical to myocardial perfusion. However, all these elements are of uncertain value and need to be revealed by randomized clinical trials to know the value of de-tunneling of myocardial bridges in HCM and its effect on the long-term outcome.The presence of myocardial bridges and tunnels causing compression of one or more major coronary artery is a potential cause of myocardial ischemia in HCM11, transapical approach12 as advocated by the Mayo clinic group, or a combination of all these approaches13,14. Additional procedures on the mitral valve are described, such as plication of the deformed and elongated mitral valve leaflets, excision of chordae with reimplantation of artificial chords, and mobilization and reorientation of the papillary muscles11,15. In the pediatric population, the changes seen in HCM are different and more severe, requiring careful and specific strategies for its surgical correction43.Myectomy remains the primary treatment option for most patients with severe drug-refractory heart failure symptoms, and it is becoming one of the safest open heart procedures when performed in experienced centers . Septal myectomy could be performed via transaortic approach, transmitral approach16,17. Septal ablation is more widely available worldwide than septal myectomy, however there are no randomized clinical trials comparing the two approaches. It was observed that the LOVT gradient is somewhat higher after ASA (average 20 mm Hg) versus myectomy (average <10 mm Hg). Myectomy is more effective than ASA in the presence of massive septal hypertrophy, which may be accompanied by midventricular obstruction. In high-volume centers that offer both myectomy and ASA, it has been observed that young patients, with massive septal hypertrophy, experienced more complete relief of symptoms after myectomy than after ASA. In older patients, who may have a lesser degree of hypertrophy, the symptomatic outcomes of the two procedures were similar. The incidence of ventricular arrythmia is higher in ASA compared to myectomy, which suggest that inducing myocardial infarction, as opposed to removal of the muscle, is responsible for these arrythmias. Transparency and reporting of an institution’s outcome are essential so that all patients can make an educated decision on the choice of procedure18–21.The current indication for surgery is for symptomatic HCM patients with resting or provoked gradient 30–50 mmHg despite maximally tolerated medical treatment. Alcohol septal ablation (ASA) could be considered as an alternative for surgical myectomy for patients for whom surgery is contraindicated, but its effectiveness is uncertain for patients with marked hypertrophy (>30 mm)22. The assessment of diastolic dysfunction is important and has a possible role in predicating symptom resolution post myectomy. Isoproterenol challenge can be utilized to guide decision-making and prognostication in patients with occult latent obstruction23.Patients with HCM can have symptoms caused by diastolic dysfunction, small cavity size or myocardial ischemia due to small vessel disease or myocardial bridges, as well as arrhythmia. However LVOTO remains one of the most important causes of symptoms and determinent of prognosis. In our experience, surgery offers the best chance of permanent gradient and symptom relief and should be the preferred option in obstructive young HCM patients, especially when atypical pathophysiological features contribute to the obstruction38. This was followed by the description of Teare who reported an autopsy series of young patients with sudden death and asymeterical hypertrophy . Septal myectomy results in a significant reduction in LA volumes and strain, paralleled by an improvement in function27.LV reverse remodeling occurs in all 3 layers of the myocardium at the myectomy site and in the free wall. It was found that age, disease extent, thickness of the myectomy, and sufficient relief of LVOT are important factors associated with LV remodeling28 (29,30. This suggests a benefit of myectomy in decreasing the risk of arrhythmia, in addition to its benefit of reliving LVOT obstruction. This could be due to the improvement of coronary circulation and subsequently less risk of myocardial ischemia and arrythmia19,31–33.These anatomical and hemodynamics changes post myectomy are reflected in excellent clinical outcomes. When performed by experienced surgeons, isolated septal myectomy can now be performed with a <1% mortality. Several surgical centers published their long-term outcome post myectomy. Currently, there are data on several decades follow-up of patients undergoing septal myectomy. Survival after myectomy has been shown to be equivalent to the expected survival of an age- and sex-matched general population and superior to that observed in patients with outflow tract obstruction who did not have the operation28 . Moreove34–36.Despite the massive need for surgical myectomy worldwide and the strong evidence for its effectiveness, application of this technique is inadequate and very sporadic. This could be due to the lack of skills and experience with the operation, reflected in the high mortality rates of the operation reported by small volume centers. On the other hand, early and late results of the operation performed in experienced centers are excellent1,37.The evolution of both knowledge and experience in understanding and treating HCM encourages clinicians and scientists to further improve the outcome of current treatments. The future of HCM management will be focused on two main aspects. First, spreading the surgical experience and skills to rest of the world by having structured and dedicated surgical training on the different surgical approaches. Secondly, by improving the outcome by developing new personalized medical treatments, imaging modalities and surgical tools. 3D printing of the heart has been used for surgical planning in patients with complex congenital heart disease, cardiac tumor, and LV aneurysms, but the use of 3D printing is not well established in HCM patients. Generating 3D printed model can provide intuitive information on the LV geometry, the extent of the hypertrophied septum, location and length of the papillary muscle, and intraventricular muscle band, allowing preoperative simulation and better precision of the surgical myectomy 1,37.


Regional differences in cardiac magnetic resonance, which can reveal catecholamine-induced myocardial injury in patients with pheochromocytoma, have not yet been assessed using 3T magnetic resonance imaging. We evaluated these differences using myocardial T1-mapping and strain analysis.We retrospectively reviewed 16 patients newly diagnosed with catecholamine-producing tumors (CPT group) and 16 patients with essential hypertension (EH group), who underwent cardiac magnetic resonance imaging between May 2016 and March 2018. We acquired 3T magnetic resonance cine and native T1-mapping images and performed feature-tracking-based strain analysis in the former.P < 0.05). Basal, but not apical, circumferential strain was significantly higher in the CPT than the EH group . Native T1 values were significantly higher in CPT than in EH patients, in both the basal septum  and the apical septum  mid-walls. In the CPT, but not in the EH group, native T1 values in the apical wall were significantly higher than those in the basal wall (P < 0.01).Global cardiac function, morphology, global strain and peak strain rate were similar, but end-diastolic wall thickness differed between groups (CPT vs EH: 10.5 ± 1.7 vs 12.6 ± 2.8 mm; 3T magnetic resonance-based T1-mapping can sensitively detect subclinical catecholamine-induced myocardial injury; the influence of catecholamines may be greater in the apical than in the basal wall. Pheochromocytomas and paragangliomas are catecholamine-producing tumors (CPTs). The prevalence of pheochromocytoma in patients with hypertension in general outpatient clinics varies between 0.2 and 0.6% . Excess The excess catecholamines and their metabolites have direct toxic as well as receptor-mediated effects on myocardial tissue , 8. ProgCardiac magnetic resonance (CMR) imaging is a valuable tool for non-invasive assessment of cardiac morphology and function, and characterization of myocardial tissue. Cine magnetic resonance (MR) images allow evaluation of left ventricular volumetric parameters as well as wall motion velocity, myocardial strain and strain rate, which can facilitate detection of local or global dysfunction using wall motion tracking methods . In termA recent report has shown that patients with pheochromocytoma had a lower left ventricular ejection fraction, lower peak systolic circumferential strain, lower diastolic strain rate and higher myocardial native T1 values than healthy controls and patients with hypertension, based on the results obtained using a 1.5T MR scanner . HoweverFurthermore, the left ventricle contains apical–basal gradients of β adrenoreceptors (βARs) (which are responsible for increased responsiveness to epinephrine) and sympathetic innervation, with the apex characterized by the highest βAR concentration . There iWe hypothesized that CMR may be able to identify the regional variance of the catecholamine-induced myocardial damage in patients with CPTs without contrast medium. We aimed to evaluate whether CMR could detect subclinical catecholamine-induced cardiac injury in patients with CPTs, as compared to patients with essential hypertension (EH), using a 3T MR scanner. We also evaluated whether there were differences in the degree of myocardial injury between the basal and apical regions using myocardial T1-mapping and wall motion tracking.This retrospective study was approved by the Ethics Committee of Tohoku University School of Medicine (#2018-1-133). The requirement for obtaining written informed consent from the patients was waived by the ethics committee.123I metaiodobenzylguanidine scintigraphy and MR imaging. Another 16 consecutive patients with EH, who underwent CMR imaging within the same period of time, were also included. These patients were referred to our institution because of refractory hypertension, but were diagnosed with EH by the same endocrinologists after ruling out secondary causes of hypertension. Exclusion criteria were a history of cardiac events  and severe renal dysfunction (estimated glomerular filtration rate <30 mL/min).Sixteen consecutive patients with newly diagnosed CPT, who underwent CMR examinations at our institution from March 2016 to May 2018 and who did not meet the exclusion criteria, were included in the study. The presence of CPT was diagnosed by endocrinologists based on serum and urinary biochemical tests, Demographic characteristics of the patients were collected; these included sex, age, BMI, body surface area, family history of EH, medical history of diabetes mellitus, smoking history, number of antihypertensive drugs, systolic blood pressure (measured at home) and disease duration . In the CPT group, 24-h urinary metanephrine and normetanephrine levels were evaluated to determine the biochemical phenotype (adrenergic or noradrenergic). Patients are classified as adrenergic if the increment of metanephrine exceeded 5% of the combined metanephrine and normetanephrine increments. Patients in whom these criteria were not fulfilled and in whom normetanephrine levels exceeded the upper limits of normal were classified as noradrenergic .All patients were imaged with a 3T whole body MR scanner  before surgery. Scanning protocols included cine and precontrast T1 maps. Native T1 maps were acquired using a modified Look-Locker inversion recovery (MOLLI) technique. Cine images were acquired at 20 frames per slice per beat in short-axis, long-axis and four-chamber views. Details of the parameters in cine and T1-mapping are provided in Supplementary Table 1 . We measured the end-systolic and end-diastolic ventricular septal wall thickness; left ventricle ejection fraction (LVEF); the end-diastolic, end-systolic and stroke volume index ; and the cardiac index (CI) from short-axis cine images. The left ventricular myocardial mass index (LVMI) was also acquired from short-axis cine images, using Simpson’s technique. We analyzed myocardial strain and strain rate using the MR Wall Motion Tracking application . Radial strain and circumferential strain were derived from the short-axis images and longitudinal strain was derived from the two- and four-chamber images. We used the average of the longitudinal strain from the two- and four-chamber images as the global longitudinal strain. We also evaluated basal and apical wall strain from segmented strain data.Two radiologists  independently measured native T1 values, for analysis of interobserver reproducibility. Regions of interest for evaluation of native T1 values were placed on the mid-wall of the basal septum and the mid-wall of the apical septum, using the short-axis and four-chamber T1 images . T1 valus.d.) for continuous variables and as the number of cases and percentages per group for categorical variables. Nonparametric data are shown as medians with interquartile ranges (IQRs). The normality of MR parameters and patient demographic data were tested using the Kolmogorov–Smirnov test. Variables between CPT and EH groups were compared using Student’s t-test or the Mann–Whitney U test. For dichotomous data, Fisher’s exact test was used to analyze the difference of proportions between the groups. We analyzed paired data using the paired t-test or the Wilcoxon signed-rank test. Interobserver reproducibility of native T1 values was evaluated using intraclass correlation coefficients (ICCs). Based on the 95% confident intervals (CI) of the ICCs, values less than 0.5, values 0.5–0.75, 0.75–0.9 and those greater than 0.9 were considered indicative of poor, moderate, good and excellent reliability, respectively. Statistical analyses were performed using SPSS version 21.0 (IBM). P < 0.05 was considered statistically significant.Descriptive statistics are presented as means and standard deviations  and longer disease duration than the CPT group  vs 2.3  years; P = 0.02). There were no significant differences between the two groups with regard to the other demographic parameters.None of the patients from the EH group were excluded from the analysis. The EH group demonstrated a significantly larger BMI (25.3 ± 3.8 vs 22.6 ± 3.2 kg/mP = 0.025). Other LV functional parameters  demonstrated no significant differences between the two groups (Left ventricular (LV) end-diastolic walls were significantly thicker in the EH group than in the CPT group ; however, apical circumferential strain was not significantly different . There was also no significant difference in the radial and longitudinal strains in the apical and basal walls between the two groups  and the apical septum . In the CPT group, native T1 values on the mid-wall of the apical septum were significantly higher than those on the basal septum ; however, the EH group did not demonstrate significant differences in native T1 values between the apical and basal walls  (P < 0.01)  in the basal segments and 0.99 (95% CI: 0.989–0.997) in the apical segments, indicating excellent reliability. Patients with CPT demonstrated significantly higher native T1 values than those with EH, in the mid-wall of both the basal septum  . The dif < 0.01) .Figure 2Among 16 CPT patients, eight were the adrenergic type and eight were the noradrenergic type. The MR parameters were not significantly different between the two groups.In this 3T CMR study of patients with CPT, we showed that the native T1 values in patients with CPT were significantly higher than those in patients with EH. Additionally, the apical septum’s native T1 values were significantly higher than those of the basal septum in the CPT group, whereas in the EH group, there were no significant differences between the apical and basal septum’s native T1 values. Furthermore, patients with CPT demonstrated significantly higher basal circumferential strain than those with EH, despite comparable LV global function.et al. have reported a systemic study of catecholamine-induced cardiac injury using a 1.5T MR scanner  cardiomyopathy , and mamA previous study showed that native T1 values in patients with pheochromocytoma decreased after surgical resection along with LV mass regression, but did not completely normalize . Follow-This study had several limitations. First, although we demonstrated regional variance of T1 values in CPT patients, the sample size was relatively small. A larger study is warranted to confirm our results. Second, native T1 values are increased by several mechanisms, such as cardiomyocyte damage, enlarged extracellular space, intramyocardial edema and fibrosis . We did In conclusion, T1-mapping using a 3T MR scanner is a sensitive tool for detecting subclinical catecholamine-induced cardiac injury and the influence of catecholamines on myocardial tissue, such as myocardial edema or fibrosis. We demonstrated that the injury may be greater in the apical than in the basal septum. Larger sample sizes and follow-up studies are needed to determine whether these subclinical findings are related to clinical prognosis and whether early intervention can minimize the catecholamine-induced myocardial injury.The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.


Heart failure (HF) imposes a major global health care burden on society and suffering on the individual. About 50% of HF patients have preserved ejection fraction (HFpEF). More intricate and comprehensive measurement-focused imaging of multiple strain components may aid in the diagnosis and elucidation of this disease. Here, we describe the development of a semi-automated hyperelastic warping method for rapid comprehensive assessment of biventricular circumferential, longitudinal, and radial strains that is physiological meaningful and reproducible. We recruited and performed cardiac magnetic resonance (CMR) imaging on 30 subjects . In each subject, a three-dimensional heart model including left ventricle (LV), right ventricle (RV), and septum was reconstructed from CMR images. The hyperelastic warping method was used to reference the segmented model with the target images and biventricular circumferential, longitudinal, and radial strain–time curves were obtained. The peak systolic strains are then measured and analyzed in this study. Intra- and inter-observer reproducibility of the biventricular peak systolic strains was excellent with all ICCs > 0.92. LV peak systolic circumferential, longitudinal, and radial strain, respectively, exhibited a progressive decrease in magnitude from healthy control→HFpEF→HFrEF: control ; HFpEF ; HFrEF . A similar progressive decrease in magnitude was observed for RV peak systolic circumferential, longitudinal and radial strain: control ; HFpEF ; HFrEF . Furthermore, septum peak systolic circumferential, longitudinal, and radial strain magnitude decreased gradually from healthy control to HFrEF: control ; HFpEF ; HFrEF . The ROC analysis indicated LV peak systolic circumferential strain to be the most sensitive marker for differentiating HFpEF from healthy controls. Our results suggest that the hyperelastic warping method with the CMR-derived strains may reveal subtle impairment in HF biventricular mechanics, in particular despite a “normal” ventricular ejection fraction in HFpEF. Heart failure (HF) with preserved ejection fraction is a clinical syndrome in which patients have symptoms and signs of HF but normal or near-normal left ventricle ejection fraction (LVEF). Nearly 30–50% of patients worldwide with HF have HFpEF , includiIn most studies, ventricular strain is measured using tissue doppler or 2-D speckle-tracking echocardiography . HoweverInterest in the RV function in HF arises from community-based studies showing that 83% of HFpEF patients have associated pulmonary hypertension and one-third of them have right ventricular dysfunction . These fIn this work, we performed further bi-ventricular strain measurement using the hyperelastic warping method to extract circumferential, longitudinal, and radial strains in three regions of the bi-ventricular unit, namely, LV, RV, and septum. The goals of this study are threefold: (i) develop a framework to simultaneously quantify circumferential, longitudinal, and radial strains in the bi-ventricle model, (ii) detect abnormalities in these three types of strains in HFpEF patients compared to HFrEF and normal controls, and (iii) study the inter- and intra-observer reproducibility of the hyperelastic warping approach in its application in HF patients.Table 1.The HF patients were recruited from the Curvedness-based Imaging Study (CBIS), a prospective study initiated in 2012. The normal control subjects were recruited from the Cardiac Aging Study (CAS) , a prospo, slice thickness 8 mm for short-axis, pixel bandwidth 1797 Hz, field of view 280–450 mm, temporal resolution ≈ 28 ms, in plane spatial resolution 0.6 mm × 0.6mm–1.1 mm × 1.1 mm, and frame rate was selected as 30 or 40 frames per cardiac cycle. Among these 30 subjects, 30 frames are used for all the short-axis view. For long-axis view, 26 subjects had 30 frames, and the other four had 40 frames.As part of the routine clinical protocol, HFpEF and HFrEF patients underwent CMR evaluation on a 3T system  with a dStream Torso coil . The same imaging protocol was applied to the control subjects. Balanced turbo field echo (BTFE) end-expiratory breath hold cine images were acquired in multi-planner short-axis and long-axis views. The short-axis view included the images from the apex to basal. The long-axis images included the two-chamber, three-chamber, and four-chamber views. The following typical sequence parameters were used: TR/TE 3/1 ms, flip angle 45Figure 1.The strain acquisition framework was implemented using a combination of open-source software: MeVisLab , Gmsh , Fenics Figure 2 shows an example of the short-axis and long-axis CMR images covering the LV and RV. They were used in contour segmentation and surface reconstruction, including short-axis images from basal to apex, and the four-chamber long-axis images.Figures 3A,B show the contour segmentation from the short-axis and long-axis images for LV endocardium, RV endocardium, and bi-ventricular epicardium . End of systole (ES) was chosen to be the time point to manually delineate the contours for model reconstruction – this is the cardiac phase when the aorta valve in three-chamber view starts to close. Depending on the size of the heart and the quality of the image, around 3–10 short-axis images and the four-chamber long-axis image were utilized. Figures 3C,D show, respectively, the contours used for surface reconstruction and the generated surfaces for the LV, RV, and bi-ventricular epicardium. Papillary muscles and trabeculated structures were not included as myocardium. After reconstruction, the model is corrected using a “WEMReducePolygons” module in Mevislab if there were mis-registration of the images.Figure 4A shows the three-dimensional bi-ventricle model, and Figure 4B shows the FEmesh model generated by GMSH  at the septum measured in the four-chamber view in MeVisLab, as shown in Figure 4B) was deformed along with a set of short-axis images during a cardiac cycle. The deformation of the FE mesh was defined as the mapping ϕ (X) = X + u(X), where u is the displacement field and X is the position. The deformation gradient was defined asHyperelastic warping is a deformable image registration technique that can be used to measure cardiac strain derived from analysis of medical images such as MRI, ultrasound, and microPET imaging . In the The forces responsible for driving the registration deformation were derived from the difference in image intensity field between two volumetric image data sets by minimizing the following energy expressionW is the hyperelastic strain density energy function related to the material model of myocardium and C = FTF is the Cauchy–Green deformation tensor. A Neo–Hookean strain energy density function was used to define W, which is given asHere, C1 is a material constant and I1 is the first invariant of the right Cauchy–Green deformation tensor. The energy term U produced an image force field responsible for the local registration of the discretized reference image R to the target image T and is expressed aswhere where γ is the penalty factor enforcing the alignment of the reference image to the target image. In summary, the FE mesh model was deformed to align with the target images via a computed image-based local body force term that depends on (1) the difference in image intensity between the template and target images, (2) the target image intensity gradient, and (3) a prescribed penalty factor.Figure 6 shows an example of the resultant deformation in the biventricular model from a normal subject computed from the hyperelastic warping method. As shown in the figure, the deformed biventricular model matched closely with the myocardium in CMR short-axis images at different cardiac time points.The hyperelastic warping approach was implemented using FEniCS . The penF was defined with ES as the initial configuration, the local Green-Lagrange strain tensor with end-diastole (ED) as the reference configuration – a more commonly used metric – was defined asThe ES biventricular geometry was used as the initial configuration for tracking because we found that the image registration worked better when the myocardial wall at all subsequent time points is thinner than the initial one, which always revealed an image intensity gradient within the initial wall volume. Since the deformation gradient I is the identity tensor and FED is the deformation gradient tensor at ED. Normal strains in the circumferential εCC, longitudinal εLL, and radial εRR directions were computed by projecting E onto these directions using εii = ie ● iEe with i ∈ . The circumferential Ce, longitudinal Le, and radial Re were prescribed using a Laplace–Dirichlet rule-based (LDRB) algorithm  are visible in the strain–time curves, particularly, in those associated with the LV.Assessment of inter- and intra-observer variability of the hyperelastic warping method was performed on a random selection of nine cases: three controls, three HFpEF, and three HFrEF patients. Inter-observer variability was assessed by comparing measurements made by two independent observers from two different centers. Intra-observation variability was obtained from repeated measurements on these nine cases, 1 month apart, by the same observer.t-tests for normally distributed data, Mann–Whitney U-tests for non-normally distributed data, and Fisher’s exact tests for categorical data. Intra- and Inter-observer variability in peak circumferential, longitudinal, and radial strains were assessed by mean bias ± SD, limits of agreement, coefficient of variation (CV), and intra-class correlation coefficient (ICC) using data from nine randomly chosen subjects. ICC between 0.4 and 0.59 was considered fair, good between 0.60 and 0.74, and excellent when ≥0.75  and SAS . Comparisons of demographics, patient characteristics, and CMR measurements between patients and control subjects were performed using independent en ≥0.75 .Table 1. Compared with normal controls, LVEF was lower in both HF groups. Between the HF groups, LVEF was larger in HFpEF patients (53 ± 7%) than the HFrEF group (25 ± 9%). Both HF groups were comparable to controls with respect to height, BSA, SBP, DBP, LVSV index, RVEDV index, and RVSV index, but exhibited higher LVEDV index, LVESV index, and LV mass index than the controls (p < 0.05). The HFpEF patients had comparable RVEF and RVESV index to controls, while the HFrEF patients had lower RVEF and higher RVESV index than both controls and HFpEF patients (p < 0.05). HF groups were comparable relative to disease history, including NYHA class, atrial flutter/fibrillation, cancer within 5 years, chronic renal insufficiency, current smoker, depression, diabetes, hyperlipidemia, hypertension, peripheral vascular disease, myocardial infarction, and stroke. NTproBNP was much higher in HFpEF patients than in HFrEF patients (p < 0.05).Study subjects in each group consist of eight males and two females with a mean ± SD age of 52.1 ± 12.7, 52.4 ± 12.5, and 52.7 ± 11.6 years for controls, HFpEF, and HFrEF patients, respectively. Demographic and clinical characteristic of study subjects are given in Table 2 shows the average values of the peak circumferential, longitudinal, and radial strains in different regions  for control, HFpEF, and HFrEF patients. All the peak circumferential, longitudinal, and radial strains in the LV were, respectively, found to gradually decrease in magnitude (p < 0.05) from control → HFpEF→ HFrEF groups . This may reveal impaired systolic LV function in both HF groups. Figure 8 shows scatter plots for the three strains in the LV. Excellent separation of controls from both the HFpEF and HFrEF patients was observed in the peak circumferential strain . Almost no overlap was found between the controls and the two HF groups of patients. Similar to the peak circumferential strain, peak longitudinal strain exhibited negligible overlap of controls with HFpEF and HFrEF . Significant differences were found between the peak radial strain of normal controls and patients. However, there was some overlap between the normal controls and the patients .p < 0.05, Table 2). Significant differences were found for all the three strain components between HFrEF and normal controls . Only longitudinal strain was observed to differ significantly between HFrEF and HFpEF . Scatter plots of RV strains are shown in Figure 9.Circumferential and radial strains in RV were smaller in HFpEF patients compared with the Controls but no significant difference was observed . However, longitudinal strain in RV was significantly decreased in the HFpEF group when compared to the controls . Radial strain was smaller but not significantly different (12.5 ± 6.38 vs. 18.5 ± 8.64). Circumferential, longitudinal, and radial strains in the septum were all depressed in the HFrEF group compared with Controls . The scatter plot of strains for septum is shown in Figure 10.Circumferential and longitudinal strains in the septum were depressed in HFpEF patients compared to the controls . Area under the ROC curve (AUC) for LV circumferential strain was 1.00 with corresponding sensitivity and specificity of 1.00. AUC for LV longitudinal strain was 0.95 with sensitivity 0.90 and specificity 0.90 (Table 3).Receiver operating characteristic (ROC) curve analysis showed that LV circumferential and longitudinal strains were superior to the septal strain for differentiating normal controls from HFpEF patients . In the Bland–Altman analysis, peak circumferential strain for LV had the best intra-observer agreement  and inter-observer agreement . Peak radial strain RV exhibited the largest intra-observer variability  and peak radial strain for LV had the largest inter-observer variability . All parameters had an excellent intra- and inter-observer agreement (ICC ≥ 0.92).In this study, we compared myocardial strains estimated using a hyperelastic warping approach in the control, HFpEF, and HFrEF patients that are comparable in age and gender. To the best of our knowledge, this research work is the first to study biventricular three-dimensional strain  based on CMR images in HF patients using the hyperelastic warping method. The major contributions of our study are as follows: (1) development of a novel framework for assessment of the biventricular mechanics of HF from CMR and (2) implementation of a viable and reproducible hyperelastic warping method for simultaneous evaluation of 3D circumferential, longitudinal, and radial strains for HF patients. The key findings from our study are as follows: (1) strains estimated in cine CMR images of HF patients using the hyperelastic are feasible and reproducible, (2) peak (absolute) circumferential, longitudinal, and radial strains in the RV, LV, and septum are highest in the normal controls followed by HFpEF to HFrEF patients, and (3) peak LV circumferential and longitudinal strain can better differentiate HFpEF patients from healthy subjects. These findings may provide a new method for simultaneous assessment of 3D biventricular strains in HF patients.2 for normal controls vs. 69.1 ± 19.5 g/m2 for HFpEF, p < 0.05, Table 1).We have found that all the three strain components  in HFpEF and HFrEF patients were decreased compared to the normal subjects. Similar conclusions are also found in In the literature, decreasing longitudinal strain was found in HFpEF patients . SpecifiTable 1, we found that the peak RV longitudinal strain is significantly decreased in HFpEF patients compared with normal controls. This finding suggests that RV function may be impaired in HFpEF patients, and peak RV longitudinal strain may be a useful in detecting this change. Consistent with previous findings, all the three RV strain components are significantly reduced in HFrEF patients. This is also consistent with the significant difference in RVEF and RVESV index between HFrEF patients and normal subjects.Right ventricular systolic dysfunction is a common feature in HFrEF that is associated with impaired functional capacity and portended a poor prognosis . The preSystematic assessment of RV function is a widely recognized challenge owing to: (1) its complex geometry, (2) the limited definition of the RV endocardial surface occasioned by trabeculated myocardium, and (3) the retrosternal position of the RV that limits echocardiographic imaging windows . It is, Septum shape and deformation  has been studied in repaired tetralogy of Fallot patients with volume overloading . HoweverOverall, LV strains have better reproducibility than the septum and RV, which is expected due to its thicker wall. Circumferential and longitudinal strains have excellent intra- and inter-observer agreement, although this is less so for radial strains that still possesses acceptable reproducibility. Peak LV circumferential strain has the best reproducibility, followed by peak LV longitudinal strain. On the other hand, peak radial strain has the worst reproducibility.Absolute peak strains obtained here appear to be smaller compared with previous studies. In normal subjects, peak LV circumferential, longitudinal and radial strains were -18.4 ± 2.9%, -19.1 ± 4.1%, and 39.8 ± 8.3% for Western population ; and -24eviously .First, to address the poor out-of-plane tracking at the ventricular base that arises because of the large out-of-plane resolution in the short-axis clinical CMR images, we have imposed a basal longitudinal displacement that varies sinusoidally with time. Despite able to obtain reasonable results even with this assumption, having a higher out-of-plane resolution  may obviate the need to impose such an assumption.Second, sample size in this study is relatively small. A larger sample size will be used in future studies to the increase statistical power.An advanced image registration method based on continuum mechanics was used to estimate three-dimensional peak circumferential, longitudinal, and radial strain in the bi-ventricular model. By dividing the biventricular unit into LV, RV, and septum, a new perspective was introduced for investigating strain in HFpEF and HFrEF and for studying the physiology of HFpEF disease. Diminishing magnitude in strain components from controls, HFpEF to HFrEF demonstrated subtle functional impairment in the LV and RV in HFpEF patients.The study was approved by the SingHealth Centralised Institutional Review Board, and written consent forms were obtained from all participants.HZ and LZ contributed to the conception of the hypothesis of the study, implementation of all the analysis, and were involved in the evaluation of the results and preparation of the manuscript. CX contributed to the development of the code and inter-observer variability. XZ contributed to data preparation and analysis. AK and R-ST contributed to patient recruitment and image acquisition. FG and JA contributed to data analysis and statistics. LCL contributed to development of the code and critically revising of the work. MG contributed to development of the code. YS contributed to the evaluation of the results and preparation of 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.


Delayed efficacy of radiofrequency energy can suppress ventricular arrhythmias after a failed ablation procedure. The implant of cardiac defibrillator for arrhythmia‐induced cardiomyopathy should be procrastinated after a period of follow‐up. Waiting for delayed efficacy is a reasonable choice to reduce the risk of complications associated with aggressive ablative approaches. Although the right ventricle outflow tract (RVOT) is the most common site of origin for OT‐VAs, these arrhythmias can less frequently originate from the left ventricle outflow tract (LVOT). In general, VAs focus is more often located in the endocardium but sometimes it has an epicardial or intramural position. Idiopathic VAs usually arise from an intramural site of origin. OT‐VAs are generally benign and may require treatment if they are symptomatic, incessant or give rise to cardiomyopathy. Radiofrequency catheter ablation (RFCA) is an effective and safe therapeutic strategy that usually leads to immediate suppression of OT‐VAs. Here, we present one case of arrhythmia‐induced cardiomyopathy (AIC) derived from intramural idiopathic VAs originating in the basal interventricular septum (IVS) with reversal of left ventricular (LV) dilatation and improved LV ejection fraction (EF) after the elimination of the arrhythmia by the delayed effect of RFCA.2A 56‐year‐old man suffering from dyspnea for mild efforts was admitted to our hospital. He denied home therapy and he had a history of systemic arterial hypertension, obesity, sleep apnea, and persistent atrial fibrillation treated with electrical cardioversion in 2015, without known recurrences.His physical examination pointed out cardiac arrhythmic activity, pulmonary congestion, jugular venous distension, hepatomegaly, and mild ankles swelling. Blood tests in the emergency department suggested acute heart failure with mild elevation of myocardial necrosis indices . Hilar congestion and cardiomegaly resulted from chest x‐ray examination.The 12‐lead ECG showed sinus rhythm with frequent monomorphic PVCs in bigeminy pattern, short runs of nonsustained VT (NSVT), and accelerated idioventricular rhythm. PVCs had right bundle branch block (RBBB) pattern, precordial transition in lead V1, and inferior QRS axis  with global hypokinesia, mild left ventricular dilatation (LVEDD 60 mm), normal LV mass, and wall thicknesses. Moreover, moderate mitral regurgitation and restrictive transmitral flow pattern were detected.The coronary angiography was performed and no coronary stenoses were found.Heart failure therapy was started. Because of the limited effectiveness of beta‐blockade on PVCs and NSVT, amiodarone was administered, but it caused prolongation of QTc interval requiring suspension of the antiarrhythmic drug.In the suspicion of acute viral myocarditis, the serology for the most common cardiotropic viruses was tested but resulted negative. Due to the impossibility to suppress arrhythmias and to perform real‐time sequences, cardiac magnetic resonance imaging (CMR) was not realized.The electrophysiological study was performed with electroanatomical mapping system  guided by intracardiac echocardiography (ICE) Figure A. The hiAfter 72 hours of observation, PVCs disappeared although there were no changes in medical therapy. One week after the PVCs disappearance, transthoracic echocardiogram showed improved systolic performance with a LVEF of 40% and slight reduction in LV diameter. After one month of follow‐up, cardiac function was completely normalized and ambulatory ECG monitoring showed stable sinus rhythm without arrhythmia recurrences.3Our patient presented a nonischemic acute heart failure associated with frequent VAs, without relevant history of heart disease and underlying structural disease. The absence of abnormal local electrogram amplitude during the high‐density substrate mapping suggested that scar zones were not present reinforcing the hypothesis of an idiopathic etiology of ventricular arrhythmia. The 12‐lead ECG analysis showed unique PVC morphology with RBBB pattern, precordial transition in lead V1, and inferior axis suggesting a ventricular outflow tract origin. OT‐VAs are generally idiopathic, occurring in healthy individuals, and more often originate from the RVOT. Four types of LVOT origins have been described in close anatomical proximity: the AMC, the anterior sites around the mitral annulus (MA), the aortic sinus cusps (ASCs), and the epicardium. OT‐VAs may arise from intramural foci and such foci are located between the epicardial fat of the left ventricular summit (LVS) and the AMC or inside the basal septum.2+ handling associated with impaired excitation‐contraction coupling resulting in impaired systolic and diastolic functions. This dysfunctional calcium metabolism results in prolongation of myocytes action potentials increasing the risk of sudden death even when normal LV size and function are restored.In the setting of acute heart failure and frequent VAs may be challenging to determine if VAs are causes or consequences of heart failure. Arrhythmia‐induced cardiomyopathy is a partially or totally reversible disease in which left ventricular dysfunction is induced or mediated by atrial or ventricular arrhythmias.Our patient was asymptomatic for palpitations and presented without abnormal cardiovascular substrate, with a high PVC burden , single PVC morphology from ventricular outflow tract, increased body mass index, high PVC coupling interval dispersion. All these features seem to be associated with the development of AIC.PVC‐mediated AIC is managed suppressing the PVCs through antiarrhythmic therapy or catheter ablation. RFCA is a highly effective therapy with success rates ranging from 70% to 90%. In PVC‐mediated AIC, the complete elimination of high burden PVC, as well as a significant PVC suppression (<5000 PVCs/d), is associated with progressive improvement in heart function and time to recovery varies between few weeks to several months.After 72 hours from the failed attempt of catheter ablation, PVCs disappeared and LV function progressively improved until normalization during follow‐up. The suppression of PVCs is probably due to the delayed efficacy of RFCA, which has been described after ablation of supraventricular arrhythmias and accessory atrioventricular connections.The awareness of the delayed efficacy of RFCA influences the management of VAs, especially for those arising from LV summit and intramural foci. In these circumstances, RF deliveries on both sides of the IVS, as well as the use of an infusion‐needle catheter, increase the risk of complications. It may be wise to interrupt the procedures waiting for the occurrence of the delayed effect of RFCA. After a failed RFCA, the implant of ICD, as well as a new ablative session, should be procrastinated after a period of follow‐up, for the possible delayed suppression of VAs.4Our patient presents a typical case of AIC secondary to PVCs with recovery of ventricular function after a failed ablation procedure for the occurrence of the delayed efficacy of RFCA. Previous studies have described this phenomenon for VAs originating from the LV summit. This case is, to our knowledge, the first description of RF delayed efficacy in VAs arising from intramural focus in the basal IVS and demonstrates that waiting for delayed efficacy may be a reasonable choice in order to reduce the risk of complications associated with more aggressive approaches.The authors declare no conflict of interest.MVM: involved in the conception and drafting the manuscript. MCG, AP, and CL: performed the electrophysiological study and the radiofrequency catheter ablation procedure. FF: critically reviewed the manuscript.