Interplay between right ventricular mechanical dyssynchrony and cardiac resynchronization therapy in patients with nonischemic dilated cardiomyopathy.

OBJECTIVE

The effect of cardiac resynchronization therapy (CRT) on right ventricular ejection fraction (RVEF) and intraright ventricular dyssynchrony (IRVD) is questionable. Furthermore, it is unclear whether baseline IRVD and RVEF influences response to CRT. The aim of this study is to evaluate the effects of CRT on RVEF and IRVD and to investigate whether baseline IRVD and RVEF impacts response to CRT.

PATIENTS AND

METHODS

Equilibrium radionuclide angiography and clinical evaluation were performed in 32 nonischemic dilated cardiomyopathy patients before and 3 months after CRT implantation. SD of the right ventricle mean phase angle expressed in degrees was used to quantify right intraventricular synchrony. RVEF was also evaluated.

RESULTS

There was no significant change in the RVEF and IRVD between the baseline and at 3 months after CRT equilibrium radionuclide angiography studies (RVEF: 40.5±10.6 vs. 40.4±10.4%, P=0.75; IRVD: 36.6±13.7 vs. 36.3±13.3°, P=0.35). Of 32 patients, 6/14 (43%) patients with baseline IRVD responded compared with 16/18 (89%) without baseline IRVD (P=0.02).

CONCLUSION

CRT did not cause any significant change in RVEF and IRVD. Patients with IRVD are less likely to respond to CRT.