Adverse prognostic implications of increased left ventricular force in hypertrophic cardiomyopathy

Abstract Background The left ventricular (LV) force, also known as elastance, serves as a load-independent indicator of contractility and can be noninvasively assessed through echocardiography. In hypertrophic cardiomyopathy (HCM), the heightened presence of the active state of myosin heads results in an increased LV force. Purpose To assess the prognostic value of increased LV elastance at rest in patients with HCM. Methods We enrolled 1420 HCM patients (age 50±16 years, 907 males, 64%) with ejection fraction (EF) ≥50%, referred for rest transthoracic echocardiography (TTE) in 10 quality-controlled labs from 7 countries. TTE assessment included peak left ventricular outflow tract gradient (LVOTG), EF, and LV force (systolic blood pressure + LVOTG/LV end-systolic volume assessed with 2-D, mmHg/mL). All patients were followed up. All-cause death was the outcome measure. Results At a median follow-up of 83 months, 150 deaths occurred (Group 1). At study entry, Group 1 patients had the same ESC-Sudden cardiac death score compared to survivors (Group 2). In Group 1 compared to Group 2, TTE showed higher values of MR severity, E/e’ , left atrial volume index, estimated systolic pulmonary artery pressure, and force (see table). At multivariable Cox analysis, only age (HR =1.08, 95% CI=1.03-1.14, p=0.001) and force > median value of 5.3 mmHg/mL (HR = 2.14, 95% CI 1.53-2.99, p=0.020) were independent predictors of mortality. Ten-year survival was 95% in the pooled first (<3.8 mmHg/mL) and second (3.8-5.2 mmHg/mL) quartiles vs 80% in the pooled third (5.3-7.8 mmHg/mL) and fourth quartiles (>7.8 mmHg/mL), see figure. Conclusion HCM patients with higher values of resting LV elastance show a worse survival, highlighting the dark prognostic side of an excess of force in these patients. Table Legends E/e’, early mitral inflow to early mitral annulus motion ratio, EF, left ventricular ejection fraction, LAVI, left atrial volume index; LVOTG, left ventricular outflow tract peak gradient, MR, mitral regurgitation; MWT, maximal wall thickness, NYHA, New York Heart Association classification, RWT, relative wall thickness; SCD risk, risk score for sudden cardiac death in hypertrophic cardiomyopathy, SPAP, systolic pulmonary arterial pressure.Table.Clinical and TTE findingsFigure.Survival in the force quartiles