Determinants of Exercise Capacity in Patients With Hypertrophic Cardiomyopathy

Background: Reduced exercise capacity reflects symptom severity and clinical outcomes in patients with hypertrophic cardiomyopathy (HCM). The present study aimed to identify factors that may affect exercise capacity in patients with HCM. Methods: In 294 patients with HCM and preserved left ventricular (LV) ejection fraction, we compared peak oxygen consumption (peak VO2) evaluated by cardiopulmonary exercise testing as a representative parameter of exercise tolerance with clinical and laboratory data, including N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP), diastolic parameters on echocardiography, and the grade of myocardial fibrosis on cardiac magnetic resonance imaging (CMR). Results: Median peak VO2, was 29.0 mL/kg/min (interquartile range [IQR], 25.0-34.0). Age (estimated beta = -0.140, P< 0.001), female sex (beta = -5.362, P< 0.001), NT-proBNP (beta = -1.256, P< 0.001), and E/e' ratio on echocardiography (beta = -0.209, P= 0.019) were significantly associated with exercise capacity. Peak VO2 was not associated with the amount of myocardial fibrosis on CMR (mean of late gadolinium enhancement 12.25 +/- 9.67%LV). Conclusion: Decreased exercise capacity was associated with age, female sex, increased NT-proBNP level, and E/e' ratio on echocardiography. Hemodynamic changes and increased filling pressure on echocardiography should be monitored in this population for improved outcomes.