Aim: The aim of this study was to analyze the relationships among exercise capacity (EC), hypertrophy, and diastolic function in nonobstructive hypertrophic cardiomyopathy (NOHCM).
Methods and results: Twenty-seven patients with NOHCM were studied. Left ventricular hypertrophy (LVH) was determined by appropriate echocardiographic indexes. For diastolic function evaluation, the following were measured: the early (E) and late (A) waves, E/A, and deceleration time of E of the mitral flow; the systolic (S), diastolic (D), and atrial reversal (AR) waves, S/D, and the atrial systolic filling fraction of the pulmonary vein flow; and the early (Ea), late (Aa) waves, Ea/Aa, and E/Ea by tissue Doppler imaging. The difference between the duration of AR and A waves (DurAR - DurA), the peak VO2, and anaerobic threshold (AT) were also determined. In these patients, the E/Ea ratio was 8.9 +/- 3.2 and DurAR - DurA was 22.6 +/- 32.6 milliseconds. The peak VO2 and AT correlated with D (r = 0.55, P = .003 and .51, P = .007, respectively) and Ea/Aa (r = 0.56, P = .007 and .45, P = .03, respectively). There was no correlation between EC and LVH.
Conclusions: Patients with NOHCM demonstrated evidences of elevated left ventricular (LV) end-diastolic pressure with normal filling pressure. EC compromise may be attributed to relaxation changes with inadequate filling of the left ventricle.