Increase In Left Ventricular Volume Research Articles

Post‐Myocardial Infarction Remodeling and Hyperkinetic Remote Myocardium in Sheep Measured by Cardiac MRI Feature Tracking

BackgroundCardiac MRI feature tracking (FT) allows objective assessment of segmental left ventricular (LV) function following a myocardial infarction (MI), but its utilization in sheep, where interventions can be tested, is lacking.PurposeTo apply and validate FT in a sheep model of MI and describe post‐MI LV remodeling.Study TypeAnimal model, longitudinal.Animal ModelEighteen lambs (6 months, male, n = 14; female, n = 4; 25.2 ± 4.5 kg).Field Strength/SequenceTwo‐dimensional balanced steady‐state free precession (bSSFP) and 3D inversion recovery fast low angle shot (IR‐FLASH) sequences at 3 T.AssessmentSeven lambs underwent test–retest imaging to assess FT interstudy reproducibility. MI was induced in the remaining 11 by coronary ligation with MRI being undertaken before and 15 days post‐MI. Injury size was measured by late gadolinium enhancement (LGE) and LV volumes, LV mass, ejection fraction (LVEF), and wall thickness (LVWT) were measured, with FT measures of global and segmental radial, circumferential, and longitudinal strain.Statistical TestsSampling variability, inter‐study, intra and interobserver reproducibility were assessed using Pearson's correlation, Bland–Altman analyses, and intra‐class correlation coefficients (ICC). Diagnostic performance of segmental strain to predict LGE was assessed using receiver operating characteristic curve analysis. Significant differences were considered P < 0.05.ResultsInter‐study reproducibility of FT was overall good to excellent, with global strain being more reproducible than segmental strain (ICC = 0.89–0.98 vs. 0.77–0.96). MI (4.0 ± 3.7% LV mass) led to LV remodeling, as evident by significantly increased LV volumes and LV mass, and significantly decreased LVWT in injured regions, while LVEF was preserved (54.9 ± 6.9% vs. 55.6 ± 5.7%; P = 0.778). Segmental circumferential strain (CS) correlated most strongly with LGE. Basal and mid‐ CS increased significantly, while apical CS significantly decreased post‐MI.Data ConclusionFT is reproducible and compensation by hyperkinetic remote myocardium may manifest as overall preserved global LV function.Evidence LevelN/ATechnical EfficacyStage 2

Longitudinal NT-proBNP: Associations With Echocardiographic Changes and Outcomes in Heart Failure.

The relationship of serial NT-proBNP (N-terminal pro-B-type natriuretic peptide) measurements with changes in cardiac features and outcomes in heart failure (HF) remains incompletely understood. We determined whether common clinical covariates impact these relationships. In 2 nationwide observational populations with HF, the relationship of serial NT-proBNP measurements with serial echocardiographic parameters and outcomes was analyzed, further stratified by HF with reduced versus preserved left ventricular ejection fraction, inpatient versus outpatient enrollment, age, obesity, chronic kidney disease, atrial fibrillation, and attainment of ≥50% guideline-recommended doses of renin-angiotensin system inhibitors and β-blockers. Among 1911 patients (mean±SD age, 65.1±13.4 years; 26.6% women; 62% inpatient and 38% outpatient), NT-proBNP declined overall, with more rapid declines among inpatients, those with obesity, those with atrial fibrillation, and those attaining ≥50% guideline-recommended doses. Each doubling of NT-proBNP was associated with increases in left ventricular volume (by 6.1 mL), E/e' (transmitral to mitral annular early diastolic velocity ratio) (by 1.4 points), left atrial volume (by 3.6 mL), and reduced left ventricular ejection fraction (by -2.1%). The effect sizes of these associations were lower among patients with HF with preserved ejection fraction, atrial fibrillation, or advanced age (Pinteraction<0.001). A landmark analysis identified that an SD increase in NT-proBNP over 6 months was associated with a 27% increase in the risk of the composite event of HF hospitalization or all-cause death between 6 months and 2 years (adjusted hazard ratio, 1.27 [95% CI, 1.15-1.40]; P<0.001). The relationships between NT-proBNP and structural/functional remodeling differed by age, presence of atrial fibrillation, and HF phenotypes. The association of increased NT-proBNP with increased risk of adverse outcomes was consistent in all subgroups.

Left ventricular rotational mechanics and left ventricular volumes: is there a relationship in healthy adults?-three-dimensional speckle-tracking echocardiography-derived insights from the MAGYAR-Healthy Study.

Left ventricular (LV) rotational mechanics play a crucial role in LV pump function by strengthening and improving its efficacy. Dependence of LV rotational parameters on left atrial volumes has already been demonstrated. The evaluation of the effect of LV rotational mechanics on LV volumes was purposed in a population of healthy subjects by three-dimensional speckle-tracking echocardiography (STE). The study comprised 175 healthy subjects with a mean age of 32.8±12.2 years (79 males). All subjects underwent a complete physical examination, laboratory assessments, standard 12-lead electrocardiography and two-dimensional Doppler and three-dimensional STE, the results of these examinations were within the normal range. Increased basal LV rotation was associated with increased LV volume measured in end-systole and impaired LV ejection fraction. Increased apical LV rotation was associated with reduced LV volumes assessed in end-diastole and in end-systole and increased ejection fraction of the LV. Elevated basal LV rotation showed associations with increased LV mass. In case of increasing basal LV rotation, apical LV rotation showed a decreasing tendency and LV twist showed a tendency of increasing. Similarly, lower basal LV rotation and increased LV twist were seen with increasing apical LV rotation. Increasing LV end-diastolic volume was associated with increasing LV volume measured in end-systole and preserved ejection fraction of the LV. Increasing LV end-systolic volume was associated with increasing LV end-diastolic volume and reduction of LV ejection fraction. Increasing LV volumes were associated with increasing LV mass. While increased LV volumes were associated with reduced apical LV rotation and twist, basal LV rotation did not show significant changes. LV rotational mechanics are strongly associated with LV volumes in healthy adults suggesting its volume-dependence.

Abstract 14052: Impact of Sex and Age on Left Ventricular Remodeling in Patients With Chronic Aortic Regurgitation

Introduction: Women and older patients with chronic aortic regurgitation (AR) have disproportionately higher rates of adverse events compared to men and younger patients, respectively. Yet, guidelines recommend same left ventricular (LV) dimension thresholds for intervention in all. While experimental animal models suggest different rates of LV remodeling by sex and age, there is paucity of data in humans with AR Methods: We included consecutive patients with isolated moderate or severe AR who were serially monitored by echo between 2010 &amp; 2016. The 2 main endpoints were change in LV volumes indexed to body surface area (LVEDVi &amp; LVESVi ) and adverse events (heart failure hospitalization, urgent surgery, or death) Results: 786 patients [mean (SD) age 58 (16) yrs &amp; 31% women] were included. Median (IQR) follow up was 25 (12-44) months. A moderate increase in LV volumes was observed overall, although women consistently had smaller LV volumes compared to men ( Fig 1 ). Similarly, compared to younger patients (&lt;60 yrs), older patients (≥60 yrs) persistently had smaller LV volumes ( Fig 1 ). Despite having smaller LV volumes, women and older patients were more sensitive to change in LV volumes, with higher rate of events per unit increase in volume e.g., HR per unit increase in LVEDVi was 1.01 (1.00-1.02) for men and 1.03 (1.01-1.07) for women ( P int =0.01) ( Fig 2 ) Conclusions: Independent of BSA, women and older patients with significant AR maintained smaller LV volumes than men and younger patients, respectively, on serial evaluation. Yet, they were more sensitive to change in LV volume. Sex and age-specific LV volume thresholds for timing of AR surgery are needed to address disparity in outcomes

Gambaran Disfungsi Diastolik pada Pasien Hipertrofi Ventrikel Kiri (LVH) Menggunakan Ekokardiografi

In cardiac patients with prolonged hypertension, it can increase the occurrence of diastolic dysfunction or systolic dysfunction which ultimately causes heart failure. LVH is an increase in left ventricular mass caused by thickening of the left ventricular wall, an increase in left ventricular volume or both. The purpose of this study was to determine the description of diastolic dysfunction in LVH patients using echocardiography at Hasna Medika Hospital Cirebon. The author used a descriptive method on 60 LVH patients as research subjects with the majority of women as many as 40 (67%). The time of the study was carried out in May-June 2021. Based on the results of the study, it was found that concentric LVH was the most common with 56 people (93%), remodeling concentric LVH with 2 people (3%), and eccentric with 2 people (3 %). In subjects with decreased diastolic dysfunction can be seen from the E/A. Of the 60 subjects in this study, 39 people had decreased LV function. There were 39 people with grade 1 diastolic dysfunction, 2 people with grade 2 diastolic dysfunction, and no grade 3 diastolic dysfunction found. The conclusion was that concentric LVH was found in 93% of the total sample, remodeling concentric in 3%, and eccentric in 3%

Comparing the diagnostic accuracy of PET and CMR for the measurement of left ventricular volumes and ejection fraction: a system review and meta-analysis.

Cardiac magnetic resonance (CMR) has been recognized as the gold standard for the evaluation of left ventricular (LV) function. Cardiac gated PET allows the simultaneous assessment of LV function with the evaluation of myocardial perfusion and metabolism. But the correlations between PET and CMR remain controversial. We conducted a systematic electronic search of PubMed, Embase and the Cochrane Library . Forest plot, spearman correlation analysis and Bland-Altman analysis were used to evaluate the correlations between PET and CMR. Pooled analysis of 13 studies showed that PET underestimated left ventricular end-diastolic volumes (LVEDV) [mean difference (MD), -15.30; 95% confidence interval (CI), -23.10 to -7.50; P < 0.001] and left ventricular end-systolic volumes (LVESV) (MD, -6.20; 95% CI, -12.58 to 0.17; P = 0.06) but not left ventricular ejection fraction (LVEF) (MD, -0.35; 95% CI, -1.75 to 1.06; P = 0.63). Overall, there were very good correlations between PET and CMR measurements for LVEDV ( r , 0.897), LVESV ( r , 0.924) and LVEF ( r , 0.898). Subgroup analysis indicated that LVEDV ≥180 ml and LVEF <40% reduced the accuracy of PET, especially the measurement of LVEF ( r , LVEDV ≥180 vs . r , LVEDV < 180 : 0.821 vs. 0.944; r , LVEF < 40% vs . r , LVEF ≥40% : 0.784 vs. 0.901). Correlations between PET and CMR measurements of LVEDV, LVESV and LVEF were excellent, but these two methods could not be used interchangeably for accurate measurements of LV volume and LVEF in patients with significantly increased LV volume and decreased LVEF.

State-of-the-Art Review: Technical and Imaging Considerations in Hybrid Transcatheter and Minimally Invasive Left Ventricular Reconstruction for Ischemic Heart Failure.

Negative left ventricular (LV) remodeling consequent to acute myocardial infarction (AMI) is characterized by an increase in LV volumes in the presence of a depressed LVEF. In order to restore the shape, size, and function of the LV, operative treatment options to achieve volume reduction and shape reconstruction should be considered. In the past decade, conventional surgical LV reconstruction through a full median sternotomy has evolved towards a hybrid transcatheter and less invasive LV reconstruction. In order to perform a safe and effective hybrid LV reconstruction, thorough knowledge of the technical considerations and adequate use of multimodality imaging both pre- and intraoperatively are fundamental. In addition, a comprehensive understanding of the individual procedural steps from both a cardiological and surgical point of view is required.

Analysis of cardiac function and morphology in genetic reference population of BXD strains reveals associated eQTLs and candidate causal and modifier genes

IntroductionThe murine recombinant inbred (RI) family of BXD strains derived from crosses between C57BL/6J (B6) and DBA/2J (D2) mice are the largest genetic reference population (GRP). The parental D2 mouse is a natural model of hypertrophic cardiomyopathy (HCM). Thus, the BXD family represents an applicable rodent model for phenotype‐genotype studies of complex cardiomyopathy traits.HypothesisGenetic background affects an expression of cardiomyopathy traits.MethodsEchocardiography, electrocardiography (ECG) and blood pressure measurements were performed in 44 BXD strains (N&gt;5/sex) at 4‐5 months of age. Cardiac traits (heart function, mass, rhythm, and arrhythmias) and blood pressure values were then associated with heart transcriptome, and expression quantitative trait loci (eQTL) mapping was performed.ResultsMore than 2‐fold variance in ejection fraction (EF%), fractional shortening (FS%), left ventricular (LV) volumes, internal dimensions (ID) and mass, as well as in thickness of LV posterior wall (LVPW), and interventricular septum (IVS) was found by echocardiography among BXDs. Varied abnormal heart rhythms including bradycardia, atrioventricular block, premature atrial or ventricular complexes, ventricular tachycardia and sick sinus syndrome were recorded among BXD strains using ECG. Parental D2 strains had significantly prolonged QT interval (62.82±9.42 ms and 53.42±1.73 ms, respectively) compared to B6 parental strains. A significant variability in systolic and diastolic BP between BXD strains was also recorded.Among male BXDs, a significant QTL of 91.0 to 97.4 Mb (LRS=18.50) was identified on chromosome (Chr) 8 that is associated with LV volumes and IDs during systole and diastole. eQTL mapping for each of the 131 genes at the QTL interval of Chr 8 identified 6 genes (Coq9, Ndrg4, Crnde, Irx3, Rpgrip1l, and Rbl2) being cis‐regulated. Among those genes, Ndrg4was found to be positively correlated with LV volumes at systole and diastole and ID traits, and negatively correlated with the cardiomyocyte size (r = ‐0.588, p = 0.025). In female BXDs, a significant QTL with LRS=20.1 was found on Chr 7 of 40.2 Mb that is associated with LVPW at diastole, where Josd2is a strong candidate gene that is cis‐regulated and significantly correlated with LVPW trait.ConclusionsOur study found variable traits of echocardiographic, electrocardiographic and blood pressure parameters are segregated among the BXD family. The cardiovascular traits significantly vary between BXD lines suggesting an influence of genetic background on expression of those traits. Traits such as reduced EF%, FS%, and LVPW and increased LV volumes are seen in patients with dilated cardiomyopathy (DCM). Increased LV mass, LV thickness, LVPW, and IVS mimic traits seen in patients with HCM. Varied abnormal heart rhythms detected in BXD strains simulate cardiac conduction abnormalities in humans. Multiple associated eQTLs defined in BXDs demonstrate that the BXD family of RI strains is a suitable model to map gene variants and identify causal genes and genetic modifiers that influence cardiovascular phenotypes including cardiomyopathies.

A Murine Model with JAK2V617F Expression in Both Hematopoietic Cells and Vascular Endothelial Cells Recapitulates the Key Features of Human Myeloproliferative Neoplasm

IntroductionAlthough murine models have provided unequivocal evidence that the JAK2V617F mutation is able to cause myeloproliferative neoplasms (MPNs), there is significant heterogeneity in disease phenotypes between different murine models and none has been able to recapitulate both the myeloproliferative phenotype and cardiovascular pathology seen in patients with MPNs. In addition, these murine models were mostly followed for less than 3-9 months and how aging affects MPN disease progression has not been studied. Endothelial cells (ECs) are an essential component of the hematopoietic niche, and they have been shown to express the JAK2V617F mutation in patients with MPNs. In this study, we investigated how MPN progresses in the JAK2V617F-bearing vascular niche during aging.MethodsJAK2V617F Flip-Flop (FF1) mice (which carry a Cre-inducible human JAK2V617F gene driven by the human JAK2 promoter) were crossed with Tie2-cre mice to express JAK2V617F specifically in all hematopoietic cells (including HSPCs) and vascular ECs (Tie2FF1).ResultsThe Tie2FF1 mice developed essential thrombocythemia to primary myelofibrosisdisease transformation with extramedullary splenic hematopoiesis during 18-month follow up. No evidence of leukemia transformation was observed in the Tie2FF1 mice. (Figure 1)Hematopoietic colony formation assays, flow cytometry analysis, and in vitro culture experiments revealed that there was a loss of both HSPC number and HSPC function in the marrow of old Tie2FF1 mice during aging, mimicking the advanced phases of myelofibrosis. In contrast, the spleen of old Tie2FF1 mice was able to maintain the expansion of JAK2V617F mutant hematopoiesis during aging and MPN disease progression. (Figure 2)These differences between marrow and spleen hematopoiesis in the old Tie2FF1 mice prompted us to investigate how aging affects the JAK2V617F mutant hematopoiesis differently in the marrow and spleen. We found that, although the JAK2V617F mutant HSCs (Lin -cKit +Sca1 +CD150 +CD48 -) from old Tie2FF1 mice were more proliferative than wild-type HSCs in both the marrow and spleen, mutant marrow HSCs were more apoptotic and senescent than wild-type HSCs in the marrow while mutant spleen HSCs were relatively protected in the spleen. Examination of the hematopoietic vascular niche revealed that marrow ECs (CD45 -CD31 +) were significantly decreased in old Tie2FF1 mice compared to age-matched control mice; in contrast, spleen ECs were significantly expanded and less senescent in old Tie2FF1 mice compared to control mice. Therefore, the different vascular niche function of the marrow and spleen could contribute to the decreased marrow hematopoiesis and expanded splenic hematopoiesis we have observed in the Tie2FF1 mice during aging. (Figure 3)Previously, we reported that the Tie2FF1 mice developed spontaneous heart failure with thrombosis, vasculopathy, and cardiomyopathy at 20wk of age. Here, we followed the cardiovascular function of Tie2FF1 mice during aging. At 18mo of age, the Tie2FF1 mice continued to demonstrate a phenotype of dilated cardiomyopathy with a moderate but significant decrease in left ventricular ejection fraction and an increase in left ventricular volume and mass compared to age-matched control mice. Histology examination revealed spontaneous thrombosis in the right ventricle, pulmonary arteries, both main (epicardial) coronary arteries and scattered coronary arterioles (microvessels) in the old Tie2FF1 mice, while age-matched Tie2-cre control mice had no evidence of spontaneous thrombosis in their heart or lungs. Despite these cardiovascular dysfunctions, there was no difference in body weight nor was there any increased incidence of sudden death between the old Tie2FF1 mice and control mice. These findings suggested that there was a persistent but compensated cardiomyopathy and heart failure in the Tie2FF1 mice during aging. (Figure 4)ConclusionCompared to other MPN murine models reported so far, the Tie2FF1 mice is the first MPN murine model that faithfully recapitulated almost all the key features of the human MPN diseases. Considering the presence of the JAK2V617F mutation in microvascular ECs isolated from patients with MPNs and the recapitulation of all the key features of human MPN diseasesby the Tie2FF1 mice, the roles of endothelial dysfunction in the hematologic and cardiovascular pathogenesis of MPN shall be further investigated. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Left atrial conduit flow rate at baseline and during exercise: an index of impaired relaxation in HFpEF patients.

AimsIn healthy subjects, adrenergic stimulation augments left ventricular (LV) long‐axis shortening and lengthening, and increases left atrial (LA) to LV intracavitary pressure gradients in early diastole. Lower increments are observed in patients with heart failure with preserved ejection fraction (HFpEF). We hypothesized that exercise in HFpEF would further impair passive LV filling in early‐mid diastole, during conduit flow from pulmonary veins.Methods and resultsTwenty HFpEF patients (67.8 ± 9.8 years; 11 women), diagnosed using 2007 ESC recommendations, underwent ramped semi‐supine bicycle exercise to submaximal target heart rate (∼100 bpm) or symptoms. Seventeen asymptomatic subjects (64.3 ± 8.9 years; 7 women) were controls. Simultaneous LA and LV volumes were measured from pyramidal 3D‐echocardiographic full‐volume datasets acquired from an apical window at baseline and during stress, together with brachial arterial pressure. LA conduit flow was computed from the increase in LV volume from its minimum at end‐systole to the last frame before atrial contraction (onset of the P wave), minus the reduction in LA volume during the same time interval; the difference was integrated and expressed as average flow rate, according to a published formula. The slope of single‐beat preload recruitable stroke work (PRSW) quantified LV inotropic state. 3D LV torsion (rotation of the apex minus rotation of the base divided by LV length) was also measurable, both at rest and during stress, in 10 HFpEF patients and 4 controls. There were divergent responses in conduit flow rate, which increased by 40% during exercise in controls (+17.8 ± 37.3 mL/s) but decreased by 18% in patients with HFpEF (−9.6 ± 42.3 mL/s) (P = 0.046), along with congruent changes (+1.77 ± 1.13°/cm vs. −1.94 ± 2.73°/cm) in apical torsion (P = 0.032). Increments of conduit flow rate and apical torsion during stress correlated with changes in PRSW slope (P = 0.003 and P = 0.006, respectively).ConclusionsIn HFpEF, conduit flow rate decreases when diastolic dysfunction develops during exercise, in parallel with changes in LV inotropic state and torsion, contributing to impaired stroke volume reserve. Conduit flow is measurable using 3D‐echocardiographic full‐volume atrio‐ventricular datasets, and as a marker of LV relaxation can contribute to the diagnosis of HFpEF.

Risk Factors for Left Ventricular Dysfunction Following Surgical Management of Cardiac Fibroma.

Surgical resection of cardiac fibromas in children reduces hemodynamic and arrhythmia burden; however, little is known about postoperative left ventricular (LV) function. We aimed to evaluate factors associated with postoperative LV dysfunction. In this retrospective observational cohort study, imaging data were reviewed from 41 patients who had undergone surgical resection of a cardiac fibroma. Tumor volume was indexed to body surface area (tumor volume index). Right ventricular tumors were excluded from analysis of postoperative ventricular function. Postoperative regional wall motion abnormality score was defined as number of wall segments with regional wall motion abnormality, and LV dysfunction was defined as LV ejection fraction <50%. Cardiovascular magnetic resonance-derived strain was low if <5%ile by previously published normative data. Of 41 patients who underwent resection at a median age of 2.1 years (range, 0.5-19), 37 fibromas were in the LV, (29 free wall and 8 septal), and 4 in the right ventricle. Preoperative median tumor volume index was 66 mL/m2 (range, 11-376). Of 37 patients with LV tumors, younger patients had larger tumor volume index and higher grades of preoperative mitral regurgitation (P<0.001). Larger tumor volume index correlated with higher postoperative regional wall motion abnormality score (P<0.001). By paired pre- and post-operative cardiovascular magnetic resonance (n=14), LV end-diastolic volume increased (mean 76 versus 101 mL/m2, P=0.011), with decreased LV ejection fraction (mean 60% versus 55%, P=0.014), a higher prevalence of low global circumferential strain (36% versus 64%, P=0.045), and decreased cardiac index (mean 4.8 versus 3.9 L/[min·m2], P=0.039). More than mild preoperative mitral regurgitation was the only independent predictor of predischarge LV dysfunction (odds ratio, 22 [95% CI, 2.8-179], P=0.008). Surgical resection of LV fibroma is associated with regional wall motion abnormality, increased LV volume, and reduced systolic function. Children with significant preoperative mitral regurgitation are at highest risk for LV dysfunction and warrant ongoing close surveillance.

Effect of data conserving respiratory motion compensation on left ventricular functional parameters assessed in gated myocardial perfusion SPECT

BackgroundRespiratory motion compromises image quality in myocardial perfusion (MP) single-photon emission computed tomography (SPECT) imaging and may affect analysis of left ventricular (LV) functional parameters, including phase analysis-quantified mechanical dyssynchrony parameters. In this paper, we investigate the performance of two algorithms, respiratory blur modeling (RBM) and joint motion-compensated (JMC) ordered-subsets expectation maximization (OSEM), and the effects of motion compensation on cardiac-gated MP-SPECT studies.MethodsImage acquisitions were carried out with a dual-detector SPECT/CT system in list-mode format. A cardiac phantom was imaged as stationary and under respiratory motion. The images were reconstructed with OSEM, RBM-OSEM, and JMC-OSEM algorithms, and compared in terms of mean squared error (MSE). Subsequently, MP-SPECT data of 19 patients were binned into dual-gated (respiratory and cardiac gating) projection images. The images of the patients were analyzed with Quantitative Gated SPECT (QGS) 2012 program (Cedars-Sinai Medical Center, USA). The parameters of interest were LV volumes, ejection fraction, wall motion, wall thickening, phase analysis, and perfusion parameters.ResultsIn phantom experiment, compared to the stationary OSEM reconstruction, the MSE values for OSEM, RBM-OSEM, and JMC-OSEM were 8.5406·10−5,2.7190·10−5, and 2.0795·10−5, respectively. In the analysis of LV function, use of JMC had a small but statistically significant (p < 0.05) effect on several parameters: it increased LV volumes and standard deviation of phase angle histogram, and it decreased ejection fraction, global wall motion, and lateral, septal, and apical perfusion.ConclusionsCompared to standard OSEM algorithm, RBM-OSEM and JMC-OSEM both improve image quality under motion. Motion compensation has a minor effect on LV functional parameters.

Abstract 15416: Longitudinal Assessment of Electrical-Mechanical Interactions in Children and Young Adults With Repaired Tetralogy of Fallot

Introduction: Electrical-mechanical interactions contribute to arrhythmias, sudden cardiac death, and right ventricular remodeling in repaired tetralogy of Fallot (TOF). Hypothesis: There are significant changes in electrocardiographic properties and electrical-mechanical interactions that occur over time after complete TOF repair and with pulmonary valve replacement (PVR). Methods: This retrospective cohort study of 177 patients, initially recruited for a cross-sectional research protocol, underwent complete TOF repair at 0.3±0.9 years with 21.5±4.2 years of clinical follow-up. We assessed ECG, Holter, cardiopulmonary exercise testing (CPET), and MRI data. We used linear mixed effects models to examine QRS duration (QRSd) and its rate of change over time, associations between comparable ECG and MRI, Holter and MRI, ECG and Holter, ECG and CPET, and pre-PVR and post-PVR results. Results: QRSd increased after TOF repair, but the rate of change decreased from 5.2 ms/year 1 year post-operatively to 1.7 ms/year 20 years post-operatively. Twenty years from TOF repair, post-operative arrhythmias included ventricular ectopy: ventricular tachycardia (4 of 20 patients) on Holter and premature ventricular contractions (14 of 19 patients) on CPET. QRSd was positively associated with right ventricular (RV) volumes, RV:left ventricular (LV) end-diastolic volume ratio, and complex ventricular ectopy on Holter; and negatively associated with RV ejection fraction (EF). The association between QRSd and RV volumes was weaker post-PVR. QRSd and its rate of change were associated with increased LV volume post-PVR. Complex ventricular ectopy was associated with lower LV EF, and significant atrial ectopy was associated with higher LV mass-to-volume ratio. Conclusions: Substantial ventricular ectopy occurs in adolescents and young adults after repair of TOF. Electrophysiologic changes included QRSd prolongation that progressively slowed. QRSd and its rate of change were associated with published risk factors for arrhythmia and sudden cardiac death, and with indications for PVR. Our ongoing research aims to identify an optimal threshold of pre-PVR QRSd and its rate of change that preserves bi-ventricular electrical-mechanical coupling post-PVR.

Definition of left ventricular remodelling following ST-elevation myocardial infarction: a systematic review of cardiac magnetic resonance studies

Abstract Background/Introduction An increase in left ventricular volumes between baseline and follow-up imaging is the main criteria for the quantification of left ventricular remodeling after ST-elevation myocardial infarction, but without consensual definition. Purpose We aimed to review the criterion used for the definition of left ventricular remodeling based on cardiac magnetic resonance imaging in studies including patients with ST-elevation myocardial infarction. Methods A systematic literature search was conducted using MEDLINE and the Cochrane Library from January 2010 to August 2019. Thirty-seven studies involving a total of 4209 patients were included. Results The median age of the patients was 59 years, 82% were male, and 93% underwent primary percutaneous coronary intervention. The median follow-up duration was 6 months (range, 3–12), and the second cardiac magnetic resonance session was performed at 6 months in 14 (38%) studies. Among these studies, 30 (81%) used a cut-off value for defining left ventricular remodeling, with a pooled left ventricular remodeling prevalence estimate of 22.8%, 95%-CI[19.4%-26.7%], and a major between-study heterogeneity (I2=82%). The seven remaining studies (19%) defined left ventricular remodeling as a continuous variable. A 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes between a baseline and a follow-up cardiac magnetic resonance imaging were the two most common criterion (13 [35%] and 9 [24%] studies, respectively). Seven studies used both end-diastolic and end-systolic vleft ventricular volumes. Conclusion(s) The definition of left ventricular remodeling using cardiac magnetic resonance following ST-elevation myocardial infarction is highly variable, among studies including highly selected patients. The most frequent left ventricular remodeling criterion were a 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes. A composite cut-off value of a 12% to 15% increase in end-systolic volume and a 12% to 20% increase in end-diastolic volume using a follow-up cardiac magnetic resonance imaging 1 to 3 months after myocardial infarction might be proposed as a consensual cut-off for defining adverse left ventricular remodeling for future large-sized, prospective studies with serial cardiac magnetic resonance imaging and long-term follow-up in unselected patients. Funding Acknowledgement Type of funding source: None

Left atrial strain is associated with left ventricular remodeling in patients with ST-elevation myocardial infarction

Abstract Background/Introduction Left ventricular remodeling (LVR) remains common and is associated with outcomes in patients with ST-elevation myocardial infarction (STEMI). Left atrial (LA) volume has been described as a predictor of outcomes in the latter population. Purpose To investigate the association between LA mechanical function using speckle tracking imaging and LVR at follow-up in STEMI patients. Methods Baseline 3D transthoracic echocardiograms were performed in 121 STEMI patients. LA global longitudinal strain was reported separately for the reservoir (LASr), conduit (LAScd), and contraction (LASct) phases. Follow-up echocardiograms were performed at 6 months. Results Mean age was 58.3±12.5 years and 98 (81%) were men. Baseline left ventricular ejection fraction (LVEF) was 46.8% [41.0, 52.9] and significantly improved to 52.1% [45.8, 57.0] at follow-up, (p&amp;lt;0.001). A lower LASct was associated with a significant dilation of left ventricle at follow-up (%end-diastolic volume increase: −1.9% [−11.0, 15.2] in the two higher LASct tertiles group vs. 19.2% [5.0, 34.3] in the lower LASct tertile group, p=0.001). A higher %end-systolic volume increase at follow-up was associated with lower LASct as well: 12.6% [−16.2, 39.8] in the lower LASct group vs. −6.8% [−23.6, 14.4] in the two higher LASct tertiles group (p=0.004). Regarding LVEF, a low LVEF at follow-up was associated with the worst tertile of all LA strains (LASr, p=0.002; LAScd, p=0.01 and LASct, p=0.01). Conclusion(s) The three components of baseline LA strain were associated with LVEF at follow-up in patients with STEMI. Some of these components were also significantly associated with lower LVEF at baseline or predictive of a significant increase in left ventricular volumes during follow-up, indicating LVR. Funding Acknowledgement Type of funding source: None

Mechanical difference of left ventricle between rabbits of myocardial infarction and hypertrophy

The analysis of cardiac wall stress is of importance to understand the development of heart failure (HF). The aim of the study is to carry out the cardiac mechanics analysis to show the changes of left ventricular (LV) wall stresses after LV hypertrophy (LVH) and myocardial infarction (MI). Here, LVH and MI were generated in rabbit hearts through the transverse aortic constriction (TAC) and the distal left circumflex (LCx) artery ligation operations, respectively. Physiological and CT measurements were carried out at postoperative 2 and 4 weeks, based on which a finite element (FE) model was developed to perform the mechanics computation. We found a gradual increase of end-diastolic myofiber stress in free wall and interventricular septum of LVH and MI (higher stress in the free wall than the septum). In the interventricular septum, the 4-weeks LVH group has the highest ED myofiber stresses (11.378 ± 3.022 kPa), while the 4-weeks MI group has the highest ED myofiber stresses (13.494 ± 2.835 kPa) in the free wall. LVH increased myocardial volume (3.49 ± 0.07 and 4.52 ± 0.26 ml at postoperative 2 and 4 weeks) while MI increased LV volume (from 2.75 ± 0.29 to 4.19 ± 0.27 ml). LVH and MI had different distributions of local myofiber stress.

Definition of left ventricular remodelling following ST-elevation myocardial infarction: a systematic review of cardiac magnetic resonance studies in the past decade.

An increase in left ventricular volumes between baseline and follow-up imaging is the main criteria for the quantification of left ventricular remodelling (LVR) after ST-elevation myocardial infarction (STEMI), but without consensual definition. We aimed to review the criteria used for the definition of LVR based on cardiac magnetic resonance imaging (CMR) in STEMI patients. A systematic literature search was conducted using MEDLINE and the Cochrane Library from January 2010 to August 2019. Thirty-seven studies involving 4209 patients were included. Among these studies, 30 (81%) used a cut-off value for defining LVR, with a pooled LVR prevalence estimate of 22.8%, 95% CI [19.4-26.7%] and a major between-study heterogeneity (I2 = 82%). The seven remaining studies (19%) defined LVR as a continuous variable. The definition of LVR using CMR following STEMI is highly variable, among studies including highly selected patients. A 20% increase or a 15% increase in left ventricular volumes between a baseline and a follow-up CMR imaging were the two most common criterion (13 [35%] and 9 [24%] studies, respectively). The most frequent LVR criterion was a 20% increase in end-diastolic volumes or a 15% increase in end-systolic volumes. A composite cut-off value of a 12 to 15% increase in end-systolic volume and a 12 to 20% increase in end-diastolic volume using a follow-up CMR imaging 3 months after STEMI might be proposed as a consensual cut-off for defining adverse LVR for future large-sized, prospective studies with serial CMR imaging and long-term follow-up in unselected patients.

Mechanical effects of MitraClip on leaflet stress and myocardial strain in functional mitral regurgitation - A finite element modeling study.

PurposeMitraClip is the sole percutaneous device approved for functional mitral regurgitation (MR; FMR) but MR recurs in over one third of patients. As device-induced mechanical effects are a potential cause for MR recurrence, we tested the hypothesis that MitraClip increases leaflet stress and procedure-related strain in sub-valvular left ventricular (LV) myocardium in FMR associated with coronary disease (FMR-CAD).MethodsSimulations were performed using finite element models of the LV + mitral valve based on MRI of 5 sheep with FMR-CAD. Models were modified to have a 20% increase in LV volume (↑LV_VOLUME) and MitraClip was simulated with contracting beam elements (virtual sutures) placed between nodes in the center edge of the anterior (AL) and posterior (PL) mitral leaflets. Effects of MitraClip on leaflet stress in the peri-MitraClip region of AL and PL, septo-lateral annular diameter (SLAD), and procedure-related radial strain (Err) in the sub-valvular myocardium were calculated.ResultsMitraClip increased peri-MitraClip leaflet stress at end-diastole (ED) by 22.3±7.1 kPa (p<0.0001) in AL and 14.8±1.2 kPa (p<0.0001) in PL. MitraClip decreased SLAD by 6.1±2.2 mm (p<0.0001) and increased Err in the sub-valvular lateral LV myocardium at ED by 0.09±0.04 (p<0.0001)). Furthermore, MitraClip in ↑LV_VOLUME was associated with persistent effects at ED but also at end-systole where peri-MitraClip leaflet stress was increased in AL by 31.9±14.4 kPa (p = 0.0268) and in PL by 22.5±23.7 kPa (p = 0.0101).ConclusionsMitraClip for FMR-CAD increases mitral leaflet stress and radial strain in LV sub-valvular myocardium. Mechanical effects of MitraClip are augmented by LV enlargement.

SAT-021 AGING, STRUCTURAL HEART DISEASE, AND SURVIVAL AMONG INCIDENT, MAINTENANCE HEMODIALYSIS PATIENTS

Abnormal echocardiogram (ECHO) findings are common in hemodialysis (HD) patients, and many of these structural heart disease (SHD) characteristics including biventricular dysfunction are strong predictors of mortality. It is uncertain how the effect of aging plays a role in the presence of SHD findings among incident chronic HD patients. Our aim was to determine the prevalence of SHD among incident HD patients in different age cohorts and the impact of these SHD characteristics on survival. We performed a retrospective cohort study including adults (≥18 years old) who initiated HD for at least thirty days and received an ECHO around the time of HD initiation between January 1st, 2001 to December 31st, 2013 with followup until March 31st, 2018. We determined the prevalence of SHD characteristics among four age groups: <55, 55-64, 65-74, and ≥75. SHD was defined by the presence of at least one of the following: ejection fraction (EF) <45%, any right ventricular (RV) dysfunction, diastolic dysfunction, left ventricular hypertrophy (LVH), increased left ventricular (LV) volume index, aortic/mitral valve disease, left atrial enlargement (LAE), and regional wall motion abnormalities (RWMA). We assessed the cumulative incidence of mortality among these age groups while accounting for the competing risk of kidney transplantation. Finally, we determined the association of SHD with mortality by age group using Cox proportional hazards modeling. A total of 654 patients met inclusion criteria during the study period. The patient age distribution was 154 (23%) age <55, 121 (19%) age 55-64, 161 (25%) age 65-74, and 218 (33%) age ≥75. The prevalence of coronary artery disease (range 32% for age <55 vs 72% ≥75) and heart failure (range 35% for age <55 vs 67% ≥75) were more likely with increasing age (trend p-value <0.001 for both). There was no difference in dialysis duration, sex, BMI, or the presence of diabetes. The majority of patients had at least 1 SHD finding ranging from 75% to 93% in those <55 and ≥ 75 years old, respectively. SHD findings were more common with increasing age (Table 1) including EF <45%, RV dysfunction, aortic/mitral valve disease, LAE and RWMA (trend p-value <0.001 for all). There was no difference in the presence of diastolic dysfunction, LVH, or increased LV volume index. The incidence of all-cause mortality was much lower in the youngest vs older age groups (Figure 1).Cox proportional hazards modeling was performed in three age groups <65, 65-74, and ≥75; patients <55 and 55-64 were combined given the relatively low event rate in those age <55 (potentially contributed to by kidney transplantation). RV dysfunction was a significant predictor of mortality in all age groups (Table 2). EF was a significant predictor in patients ≥65 but not those age <65. LVH was unexpectedly associated with decreased mortality in patients <65.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT) SHD is common even in the youngest incident HD patients. In general, the prevalence of SHD abnormalities increases with age except diastolic dysfunction, LVH, or increased LV volume index. RV dysfunction is a strong predictor of mortality among all age groups, while other SHD characteristics including EF and LVH differ in their impact on survival.

In ST-segment elevation myocardial infarction, the echocardiographic parameters of microvascular obstruction are not associated with left ventricular remodeling at five years of follow-up.

The correlation between the echocardiographic Doppler flow parameters of microvascular obstruction (MVO) and coronary wedge pressure (CWP) measured as a marker of severe compressive microvascular dysfunction and a predictor of adverse left ventricular remodeling was evaluated in a group of high-risk acute anterior myocardial infarction survivors. Twenty-four patients with mechanically reperfused anterior STEMI were divided into two groups based on the 38mmHg CWP cutoff for adverse left ventricular remodeling. Diastolic deceleration time (DDT), coronary flow reserve (CFR), systolic retrograde flow, peak systolic and peak diastolic velocities in the infarct-related artery were determined 3-5days after revascularization. An echocardiographic 20% increase in left ventricular volumes defined adverse remodeling. No significant differences were recorded between groups with regard to the echocardiographic parameters of MVO. No significant correlation was identified between CWP on one side and DDT (P=0.30) and CFR (P=0.39) on the other, irrespective of total ischemic time and extracted thrombus length. No difference in 5years of follow-up left ventricular remodeling was detected in patients with DDT<900msec as compared to those with DDT≥900msec. The medium increase in left ventricular end-systolic volume in patients with low CWP was 24.78%, while it reached 127.27% (P=0.03) in patients with CWP>38mmHg. Coronary wedge pressure did not correlate with the surrogate parameters for MVO, but it was a predictor of left ventricular remodeling. None of the echocardiographic MVO parameters was associated with adverse remodeling at 5years of follow-up.