Larsen, Carolyn

Introduction: Patients with hypertrophic cardiomyopathy (HCM) have lower peak oxygen uptake (VO2) than healthy peers. The mechanism of peak VO2 limitation in HCM has not been fully elucidated. Hypothesis: We assessed the hypothesis that resting echocardiographic parameters are predictive of peak VO2 in HCM. Methods: A retrospective review of adult HCM patients seen at a tertiary referral center from 2006-2012 was performed. Patients who underwent a comprehensive echocardiogram and cardiopulmonary treadmill exercise test within 1 week were included. Multivariate modeling was used to identify predictors of peak VO2 adjusting for age, sex, body mass index, beta blocker use, diabetes, smoking, systolic blood pressure, and obstructive HCM. Results: Five hundred and forty one patients met the inclusion criteria. The average age was 52 +/- 0.65 years, 62% were male, 78% had obstructive HCM, and 42% were NYHA class III or IV. Independent predictors of peak VO2 included averaged left ventricular (LV) longitudinal peak systolic strain (p<0.01) and right ventricular systolic pressure (RVSP) (p<0.01) (Figure 1). Obstructive versus non-obstructive HCM, grade of diastolic dysfunction, LV mass and wall thickness, left atrial volume index, right ventricular dysfunction and moderate or greater mitral or tricuspid regurgitation were not independent predictors of peak VO2. Conclusions: In conclusion, higher RVSP and less negative LV longitudinal peak systolic strain were moderate independent predictors of lower peak VO2. These findings confirm the hypothesis that resting echocardiographic parameters are predictive of peak VO2 in HCM. Further study of the relationship between echocardiographic findings and outcomes on cardiopulmonary exercise testing may help elucidate the mechanisms of exercise limitation in HCM.

Introduction: Impaired peak VO2 and obesity are known predictors of morbidity and mortality in Hypertrophic Cardiomyopathy (HCM). The purpose of this study is to determine the degree of exercise impairment due to excess weight in patients with HCM. Methods: Adult HCM patients who underwent cardiopulmonary treadmill testing at our tertiary referral center from 2006 - 2012 and had consented to research participation were identified retrospectively. Percent predicted peak VO2 was calculated by the Astrand formula for men and the Jones formula for women which adjust for age and gender. Baseline echocardiographic features obtained within 1 week of exercise testing and % predicted peak VO2 were compared among four groups of patients stratified by body mass index (BMI). Results: 510 patients were identified, with a mean age at diagnosis of 44.3 ± 16.1 years, 186 (36.5%) female. Mean BMI at the time of cardiopulmonary exercise testing was 29.7 ± 5.3 and 227 (44.6%) patients had a BMI ≥ 30. Overweight and obese patients were older and were more likely to be male than their normal weight peers. However, there was no significant difference in ejection fraction (EF), resting left ventricular outflow tract gradient, right ventricular systolic pressure (RVSP), or septal thickness among the groups. HCM patients show impaired peak VO2 across all BMI groups. While peak VO2 increased progressively across BMI groups consistent with greater O2 demand generated by higher body weight, the adjusted peak VO2 in mL/kg/min fell progressively, indicating progressively greater performance impairment with increasing BMI despite similar degrees of cardiac impairment (p <0.0001) (Table 1). Conclusion: Increased BMI is associated with reduced exercise performance in a graded manner in HCM patients independent of cardiac impairment identified on echocardiography.

Abstract Background Exercise intolerance is the cardinal manifestation of heart failure (HF), yet its underlying mechanism(s) remain poorly understood. Measures of ventricular function such as ejection fraction often have no relationship with exercise capacity in HF. 2D-STE has proved to be more reliable method to evaluate myocardial mechanical function. Our hypothesis is Resistance exercise training (Resist-HFpEF) will improve exercise tolerance and exertional symptoms in patients with HFpEF. Purpose The study aims to evaluate myocardial mechanical function by strain imaging during resistance exercise training in Heart Failure patients with Preserved Ejection Fraction (HFpEF) Methods This is a single centre prospective pilot study. 24 HFpEF patients were enrolled and their baseline comorbidities were recorded. Baseline 2D-STE imaging was performed at rest and during exercise (Visit 1). Patients were then randomized to either a novel resistance exercise training program for 36 sessions (3 sessions per week for 12 weeks) or a standard of care control group. 2D STE imaging was then repeated at follow-up (Visit 2). Peak Global Longitudinal strain (GLS), systolic strain rate (SSR), early diastolic strain rate (SRe) were measured offline. Results Mean age of the Rehab cohort was 68.57±10.52 years and the control cohort was 68.1±6.47 years. 23 study subjects were male (96%). 17% of the study subjects were hypertensive, 63% were diabetic, 42% had NYHA I, 46% had NYHA II and 13% had NYHA III of heart failure. The mean LV ejection fraction in the control and Rehab group after the training program at rest was 61.88±2.26% & 54.74±2.07% (p-value 0.04) and during exercise was 59.90±2.05% and 53.13±2.05% (p-value 0.04). The peak GLS was −18.80±4.29% and −17.7±2.21% in controls during rest and exercise at Visit 1 (p-value 0.27) while the rehab cohort had −18.71±4.7% and −20.82±2.4% respectively (p-value 0.0268). The peak GLS was −17.40±3.05% and −17.96±2.65% in controls during rest and exercise at Visit 2 (p-value 0.3430) while rehab cohort had −17.97±6.21% and −16.57±3.82% respectively (p-value 0.67). (Figure 1a and 1b shows GLS, SRS, SRe at Baseline and after exercise program respectively) Conclusion This pilot study suggest systolic and diastolic reserve can be measured reliably during low grade exercise. These results could reflect improvement in clinical status and exercise tolerance. Figure 1. Comparison of peak GLS, SSR, SRe amongst HFpEF patients at rest and during exercise before and after the rehab training program. Funding Acknowledgement Type of funding source: None

AbstractIntroductionTricuspid valve regurgitation (TR) is a frequent finding in patients with pulmonary arterial hypertension (PAH). However, its prognostic significance and relation to PAH, while suspected, are poorly understood. We assessed 727 consecutive patients with newly diagnosed PAH who underwent transthoracic echocardiographic evaluation of tricuspid valve function.ObjectivesThe study objective was to determine the association of TR presence and severity with patient characteristics, pulmonary artery hemodynamics and outcome.MethodsConsecutive patients with newly diagnosed PAH (N = 727 with group 1 pulmonary hypertension) underwent transthoracic echocardiographic evaluation of tricuspid valve function at diagnosis. The primary study end point was all‐cause mortality or lung transplantation.ResultsIn this population, 702 patients (96.5%) had TR; in 165 patients (23%), TR was severe. Compared with those with no or mild TR by echocardiography criteria, patients with severe TR had shorter mean (SD) 6‐minute walk distances (285 [125] m vs 360 [121] m; P = .02) and higher levels of B‐type natriuretic peptide (695 [672] pg/dL vs 328 [300] pg/dL; P < .05). Severe TR was associated with greater right atrial dilatation (91% vs 47%; P = .004) and right ventricular (RV) dilatation (92% vs 51%; P = .008), greater right atrial pressure (mean [SD] 15 [7] mm Hg vs 10 [6] mm Hg; P < .001) and lower cardiac index (mean [SD], 2.2 [0.7] L/min/m2 vs 2.8 [0.9] L/min/m2; P < .001). Severe TR was strongly predictive of greater 5‐year mortality risk after adjustment for age, sex, functional class, 6‐minute walk distance, diffusing capacity, RV size and pulmonary vascular resistance index (adjusted hazard ratio, 1.83; 95% CI, 1.38‐2.41; P < .001).ConclusionsSevere TR was a significant predictor of long‐term mortality rate in PAH, and TR severity correlated with PAH severity.