Background: Cardiac resynchronization therapy (CRT) is an emerging treatment for heart failure patients with left bundle branch block; in these patients left ventricle filling pattern (LVFP) abnormalities are recognized as cause of symptoms and predictors of outcome. We investigated the effects of CRT on diastolic function and the prognostic value of LVFP in patients on CRT.
Methods: 65 patients treated with CRT were studied over a 12 months period. At baseline, according to defined echocardiographic criteria, restrictive LVFP (RFP) was present in 25 patients, whereas 40 patients showed no-RFP.
Results: After CRT, opposite changes occurred in the two groups. In no-RFP patients, early-to-atrial filling velocity ratio (E/A) increased from 0.8+/-0.3 to 1.0+/-0.6 (p=0.006) and E wave deceleration time (DT) decreased from 234+/-83 ms to 196+/-51 ms (p=0.028). In 13 RFP patients, E/A decreased from 2.2+/-0.9 to 0.8+/-0.5 and DT increased from 128+/-43 ms to 205+/-52 ms (both p<0.001), leading to reversal of RFP. In both groups, clinical, functional and echographic benefits were evident, with mortality rates of 5% (2/40) and 15% (2/13) respectively. The remaining patients showed persistence of RFP (E/A and DT unchanged), no improvement and a mortality rate of 42% (5/12) (p=0.005, versus no-RFP).
Conclusions: CRT improves diastolic function, inducing also reversal of LVFP in a consistent number of RFP patients. The persistence of RFP after CRT is associated to an extremely poor prognosis.