Federica Re1, Elisabetta Zachara2, Andrea Avella2, Pasquale Baratta2, Michele di Mauro3, Massimo Uguccioni2, Iacopo Olivotto4. 1. Cardiology Division, Cardiac Arrhythmia Center and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, Italy. Electronic address: re.federica77@gmail.com. 2. Cardiology Division, Cardiac Arrhythmia Center and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, Italy. 3. Cardiology, University of L'Aquila, Italy. 4. Referral Center for Cardiomyopathies, Careggi University Hospital Florence, Italy.
Abstract
BACKGROUND: Exercise limitation in hypertrophic cardiomyopathy (HCM) patients is often attributed to left ventricular outflow tract (LVOT) obstruction and diastolic impairment. However, these features assessed at rest fail to predict performance. To evaluate their variations and interplay during effort in HCM, we performed echocardiographic assessment of diastolic function and outflow obstruction during cardiopulmonary test (CPX). METHODS: We included 197 HCM patients (mean age 45±15years, 129 males), undergoing CPX. Diastolic dysfunction (DD) grade was measured at baseline and at peak exercise. Oxygen consumption (VO2 max) values <75% of maximum predicted were considered abnormal. RESULTS: One hundred-seven patients (54%) had DD grade II-III at rest (Rest DD), 40 (20%) showed preserved diastolic function (grade 0/I) both at rest and on effort (No DD). The remaining 50 patients (25%) had a grade 0/I pattern at rest but exhibited impaired diastolic reserve on exercise (Latent DD). Latent DD was associated with higher prevalence of patients with VO2<75% in both the non-obstructive and the latent-obstructive group: at multivariate regression analysis, left atrium volume index, LV obstruction at rest and rest or latent DD were significantly associated with lower peak VO2. Excluding rest-obstructive patients from the analysis, rest- or latent DD were the only determinants of exercise impairment (latent-obstructive, OR 8.9; 95% CI 1.5-18.8; p=0.012; non-obstructive, OR 2.2; 95% CI 1.0-5.8; p=0.03). CONCLUSION: Latent DD is a major determinant of exercise intolerance in HCM. Comprehensive assessment of outflow obstruction and diastolic reserve during cardiopulmonary test represents an important adjunct to clinical management.
BACKGROUND: Exercise limitation in hypertrophic cardiomyopathy (HCM) patients is often attributed to left ventricular outflow tract (LVOT) obstruction and diastolic impairment. However, these features assessed at rest fail to predict performance. To evaluate their variations and interplay during effort in HCM, we performed echocardiographic assessment of diastolic function and outflow obstruction during cardiopulmonary test (CPX). METHODS: We included 197 HCM patients (mean age 45±15years, 129 males), undergoing CPX. Diastolic dysfunction (DD) grade was measured at baseline and at peak exercise. Oxygen consumption (VO2 max) values <75% of maximum predicted were considered abnormal. RESULTS: One hundred-seven patients (54%) had DD grade II-III at rest (Rest DD), 40 (20%) showed preserved diastolic function (grade 0/I) both at rest and on effort (No DD). The remaining 50 patients (25%) had a grade 0/I pattern at rest but exhibited impaired diastolic reserve on exercise (Latent DD). Latent DD was associated with higher prevalence of patients with VO2<75% in both the non-obstructive and the latent-obstructive group: at multivariate regression analysis, left atrium volume index, LV obstruction at rest and rest or latent DD were significantly associated with lower peak VO2. Excluding rest-obstructive patients from the analysis, rest- or latent DD were the only determinants of exercise impairment (latent-obstructive, OR 8.9; 95% CI 1.5-18.8; p=0.012; non-obstructive, OR 2.2; 95% CI 1.0-5.8; p=0.03). CONCLUSION: Latent DD is a major determinant of exercise intolerance in HCM. Comprehensive assessment of outflow obstruction and diastolic reserve during cardiopulmonary test represents an important adjunct to clinical management.