Prognostic Value of Exercise Echocardiography in Patients with Hypertrophic Cardiomyopathy

Abstract

Although exercise echocardiography may assess left ventricular (LV) function and LV outflow tract (LVOT) gradients during exercise in patients with hypertrophic cardiomyopathy (HCM), its value for predicting outcomes has not been studied. The aim of this study was to determine whether exercise echocardiography predicts outcomes in patients with HCM. LV function and LVOT gradients were evaluated during exercise echocardiography in 239 patients with HCM. Sixty patients (25.1%) had LVOT obstruction at rest, and 43 (18%) developed exercise-induced LVOT obstruction. The mean resting LV ejection fraction was 69 ± 9%, and the mean resting wall motion score index was 1.00 ± 0.06. Wall motion abnormalities during exercise were seen in 19 patients (7.9%). During follow-up of 4.1 ± 2.6 years, 19 patients had hard events (cardiac death, cardiac transplantation, appropriate discharge of a defibrillator, stroke, myocardial infarction, or hospitalization for heart failure), and 41 patients had composite end points of hard or soft events (including atrial fibrillation and syncope). Exercise wall motion abnormalities occurred in 31.5% of patients with hard events compared with 5.9% of patients without hard events (P < .001). After adjustment, LV wall thickness (hazard ratio [HR], 1.13; 95% confidence interval [CI], 1.05-1.21; P = .002), resting wall motion score index (HR, 21.59; 95% CI, 2.38-196.1, P = .006), and metabolic equivalents (HR, 0.74; 95% CI, 0.63-0.88; P = .001) remained independent predictors of hard events. Change in wall motion score index was also independently associated with hard events (HR, 52.30; 95% CI, 3.81-718.5; P = .003) and with the composite end point (HR, 39.51; 95% CI, 3.79-412.4; P = .002). LVOT obstruction was not associated with either end point. Assessment of exercise capacity and LV systolic function during exercise echocardiography may have a role in risk stratification of patients with HCM.