Effects of cardiac resynchronization therapy on right ventricular function--evaluation with tissue Doppler echocardiography.

Introduction And Objective: Ventricular resynchronization therapy improves cardiac function in patients (pts) with dilated cardiomyopathy and intraventricular conduction disturbances. The effects of ventricular resynchronization on right ventricular function have been poorly studied. Tricuspid annular motion can be studied with tissue Doppler echocardiography, which enables quantitative assessment of right ventricular function. The aim of this study was to evaluate the effects of ventricular resynchronization on right ventricular function with pulsed tissue Doppler.

Patients: We studied ten pts, eight male, mean age 65 +/- 10 years, with dilated cardiomyopathy, intraventricular conduction disturbances and heart failure, New York Heart Association functional class III or IV. Five pts had coronary artery disease and the others idiopathic dilated cardiomyopathy. All pts had an implanted cardioverter-defibrillator with ventricular resynchronization.

Methods: Before and one month after device implantation right ventricular function was evaluated with pulsed wave tissue Doppler study of tricuspid annular motion. The maximum velocity of the S wave (MV-S), E wave (MV-E), and A wave (MV-A), E/A ratio, isovolumetric contraction time (IVCT) and ejection time (ET) were determined. Right ventricular size and left ventricular ejection fraction (EF) were measured. Functional class before and after implantation was assessed.

Results: MV-S, MV-E and MV-A did not change significantly. The E/A ratio decreased significantly (p = 0.017). There were no differences in IVCT and ET, nor in right ventricular size before and after resynchronization. EF improved in all but one patient (p = 0.003). All pts had an improvement in functional class, except the one without increased EF.

Conclusions: Ventricular resynchronization therapy does not appear to have a deleterious effect on right ventricular function in pts with dilated cardiomyopathy and intraventricular conduction disturbances. The main beneficial effect of this type of therapy appears to be improvement in left ventricular function.