Objective: To measure ventricular contractile synchrony in patients with ischemic left ventricular (LV) systolic dysfunction and to evaluate the effects of carvedilol on contractile synchrony.

Methods: We measured intraventricular conduction delay by means of phase analysis in 164 patients of the CHRISTMAS Study, who underwent radionuclide ventriculography (RNVG) at the time of randomization and at the end of the maintenance phase of treatment with carvedilol or placebo (PL).

Results: The degree of interventricular dyssynchrony (difference in LV and right ventricular (RV) mean phase angles) did not change from baseline to the final visit in the PL group (11 ±17 vs 12 ±9), while it improved in the carvedilol group (13 ±17 vs 9 ±14; p<0.01). The degree of intraventricular dyssynchrony (std deviation of the mean phase angle) significantly improved for LV in the carvedilol group (54 ±18 vs 51 ±19; p=0.04), but did not change for both the RV (41 ±12 vs 41 ±11) and the LV (57 ±14 vs 56 ±19) in the PL group, and for the RV in the carvedilol group (40 ±14 vs 30 ±10).

Conclusion: Treatment with carvedilol in patients with ischemic cardiomyopathy improves interventricular contractile synchrony between the LV and RV and intraventricular contraction synchrony of the LV. This is a new and additional mechanism by which carvedilol exerts beneficial effects on left ventricular function in ischemic heart failure.

Citation: Supplement to Journal of the American College of Cardiology, March 19, 2003, Vol. 41, Issue 6, Suppl. A