Effect of intraventricular dyssynchrony on diastolic function and exercise tolerance in patients with heart failure

Intraventricular dyssynchrony may contribute to the severity of heart failure [congestive heart failure (CHF)]. We assessed the correlates of intraventricular dyssynchrony and evaluated dyssynchrony as an independent predictive variable of exercise intolerance in CHF patients. Eighty-one CHF patients (66 +/- 9 years) underwent cardiopulmonary exercise test. Left ventricular (LV) diastolic function was evaluated by transmitral patterns and tissue Doppler. Intraventricular dyssynchrony was calculated according to time intervals between the onset of QRS and the onset of systolic velocities of basal septum and lateral wall. We divided the patients based on the mean value (40 ms) of dyssynchrony. Patients with intraventricular dyssynchrony (> 40 ms) showed higher New York Heart Association class (2.7 +/- 0.6 vs. 2.2 +/- 0.4, P < 0.001), higher brain natriuretic peptide (BNP) (415 +/- 478 vs. 194 +/- 205, P = 0.014), more frequent restrictive transmitral pattern (33 vs. 7%, P = 0.013), higher E/E(a) (13 +/- 7 vs. 10 +/- 6, P = 0.016), lower mitral annulus peak systolic velocity (4.5 +/- 1.1 vs. 5.5 +/- 1.5 cm/s, P = 0.01), and peak oxygen consumption (13.8 +/- 3.5 vs. 18.1 +/- 3.9, P < 0.001), than patients without dyssynchrony (< 40 ms). Predictors of exercise tolerance were intraventricular dyssynchrony (P = 0.035), log BNP (P = 0.003), and E/E(a) (P = 0.004). Intraventricular dyssynchrony correlates with higher LV filling pressure and lower ejection fraction and it is an independent predictor of poor aerobic capacity; it may be helpful for functional evaluation of CHF patients.