6 ventricular inter‐ and left ventricular intra ventricular systolic asynchrony in patients with dilated cardiomyopathy and the effect of cardiac resynchronization therapy

Aim: Data dealing with the effect of cardiac resynchronization therapy (CRT) on myocardial or interventricular systolic asynchrony derived by pulsed Doppler tissue imaging (PDTI) and pulsed flow Doppler imaging are scare. The purpose of this study was to evaluate ventricular inter- and left ventricular intraventricular systolic asynchrony and to describe the effects of CRT on Doppler imaging in patients with dilated cardiomyopathy (DCM) and reduced left ventricular ejection fraction (LVEF). Methods: 217 consecutive patients (96 patients with left bundle branch bloc[LBBB]) with DCM underwent a standard and PDTI echocardiography examination. We measured the interval between Q wave in the electrocardiogram and the beginning of the systolic velocity profile (Q - Sb) recorded from the right and left ventricular outflow tract by pulsed Doppler imaging (PWD) and from 5 basal segments (right ventricle, septal-, lateral-, anterior-, inferior left ventricle) by PDTI from an apical approach. In 18 patients a biventricular pacing system was implanted and the effect of the cardiac resynchronization therapy was evaluated 1 month after implantation by echo examination. Results: A high-grade interventricular systolic asynchrony (> 60 ms) was measured in 3 patients (2.5%) without LBBB versus 33 patients (16%) with LBBB. A severe left ventricular intraventricular systolic asynchrony (> 60 ms) was documented in 33 patients (27%) without LBBB versus 27 patients (28%) with LBBB. CRT in 18 patients reduced the interventricular systolic asynchrony from 52 ± 29 (20–116) ms to 14 ± 10 (0–32) ms (p < 0.01). Left ventricular intraventricular systolic asynchrony was reduced from 87 ± 35 (42–168) ms to 29 ± 14 (4–52) ms (p < 0.001). All patients with CRT showed an improvement in NYHA functional status. Conclusions: Patients with LBBB and DCM showed a significant intense degree of interventricular systolic asynchrony compared with patients without LBBB. The incidence of high-grade left ventricular intraventricular systolic asynchrony was not influenced by LBBB. CRT is able to reduce inter- and left ventricular intraventricular systolic asynchrony. We recommend the use of PWD and PDTI in all patients with DCM as an additional important selection criteria for CRT.