Advanced Heart Failure With Preserved Systolic Function in Nonobstructive Hypertrophic Cardiomyopathy

BACKGROUND: In hypertrophic cardiomyopathy (HCM), heart transplant has been predominantly confined to patients with systolic dysfunction. An underappreciated HCM subset comprises patients with preserved left ventricular (LV) systolic function who may also require consideration for transplantation. Therefore, we sought to define the clinical profile and occurrence of advanced heart failure among patients with nonobstructive HCM and preserved systolic function. METHODS AND RESULTS: Databases from 2 referral centers comprising 2100 HCM patients were interrogated. Forty-six nonobstructive HCM patients (2.2%) either received or were listed for heart transplant, including 20 with normal systolic function (ejection fraction ≥50%). At transplant listing, these 20 patients were 42±13 years old, each in New York Heart Association functional class III/IV with ejection fraction of 62±7%. LV was hypertrophied with maximum wall thickness of 22±4 mm and nondilated (end-diastolic dimension, 39±7 mm). Cardiovascular magnetic resonance in 10 (of 15) patients showed no or minimal fibrosis (≤5% LV mass). Elevated LV end-diastolic or pulmonary capillary wedge pressure, consistent with diastolic dysfunction, was present in 15 patients (75%). LV filling was impaired by echocardiographic measures in all patients, including a restrictive inflow pattern in 8 (40%). In 2 patients, traditional criteria for transplant were absent, including peak VO2 >14 mL/kg/min. Heart transplantation was performed in 12 patients with each alive and without cardiovascular symptoms, 2.3±1.7 years later. CONCLUSIONS: A previously under-recognized segment of the broad HCM clinical spectrum consists of nonobstructive patients with advanced heart failure, in the presence of preserved systolic function, for whom heart transplant is the sole definitive therapeutic option.