Clinical and echocardiographic correlates of improvement in left ventricular diastolic function after cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves systolic function in heart failure (HF). However, the effects of CRT on left ventricular (LV) diastolic function are not fully understood. The aim of this study was to determine clinical and echocardiographic correlates of improvement in LV diastolic function after CRT. Fifty-four patients (mean age, 61.9 +/- 10.5; 43 men; mean LV ejection fraction 24.6 +/- 4.0%) with severe HF were enrolled in the study. Pulsed-wave Doppler-derived mitral inflow indices and colour M-mode flow propagation velocities were obtained. Tissue Doppler imaging included measurements of systolic and diastolic (e') velocities at four mitral annular sites and mitral E/e' ratio for estimating LV filling pressure. Plasma brain natriuretic peptide (BNP) levels were assessed 1 day before the CRT. Response to CRT was defined as a decline in LV end-systolic volume >= 10%. In responder group, septal E/e' (18.66 +/- 8.78 vs. 12.81 +/- 5.95, P < 0.01), E/Vp (2.44 +/- 1.10 vs. 1.59 +/- 0.65, P < 0.001), left atrial volume index (43.95 +/- 17.73 vs. 41.99 +/- 18.24 mL/m(2), P < 0.001), and plasma BNP levels [270.5 (20-2766) vs. 47.2 pg/mL (8-802)] decreased significantly. There was no significant difference in indices of diastolic function and plasma BNP levels among non-responders. Spearman's correlation analyses revealed a negative correlation between decline in plasma BNP levels and delta septal E/e' (r = -0.517, P = 0.001), delta mitral E/Vp (r = -0.650, P = 0.001), and delta LAVI (r = -0.505, P = 0.001), respectively. Left ventricular diastolic indices after CRT improved in the responder group, but there was no significant change in these indices among non-responders. Left ventricular diastolic performance after CRT is associated with the decline in BNP levels.