0372: Impact of exercise mitral regurgitation on hypertrophic cardiomyopathy outcomes

Abstract

Rest echocardiography plays a role in the diagnosis and risk stratification of hypertrophic cardiomyopathy (HCM). Indeed, left atrial enlargement, severe left ventricle (LV) hypertrophy and rest LV outflow tract (LVOT) gradients ≥50mmHg are sudden cardiac death risk factors as highlighted in recent guidelines. Conversely, exercise echocardiography findings play only a limited role in prognosis evaluations. Therefore, we sought to determine whether exercise induced changes in myocardial and valvular functions could improve HCM risk stratification. Consecutive HCM patients with a preserved LV ejection fraction underwent standardized exercise echocardiography (including the assessment of myocardial function, dynamic left intra-ventricular gradient and valvular regurgitations) at baseline and were clinically followed for a median of 29.3 months. The primary endpoint was a composite criterion that included death from any cause, cardiorespiratory arrest, and hospitalization for a cardiovascular event. A total of 126 patients were included. Eighteen patients reached the primary endpoint. According to univariate Cox regression analysis, exercise LVOT gradient ≥50mmHg (HR=3.31, p=0.01) and significant (≥2/4) exercise mitral regurgitation (HR=3.64, p<0.01) were associated with the primary endpoint. Patients with significant MR had significantly higher rest and exercise LVOT gradients (p=0.001 and p=0.001) and larger left atria (p<0.001). Significant exercise mitral regurgitation appears to significantly impact the prognoses of HCM patients, and it is also associated with higher LVOT rest and exercise gradients.