Effects of cardiac resynchronization therapy on right ventricular function during rest and exercise, as assessed by radionuclide angiography, and on NT-proBNP levels.

Aim: We carried out this study to investigate mid-term effects of cardiac resynchronization therapy (CRT) on right ventricular (RV) function and neurohormonal response, expressed by N-terminal pro-brain natriuretic peptide (NT-proBNP), in heart failure patients stratified by baseline RV ejection fraction (RVEF).
Methods and Results: Thirty-six patients with nonischemic dilated cardiomyopathy underwent technetium-99m radionuclide angiography with bicycle exercise immediately after CRT implantation (during spontaneous rhythm and after CRT activation) and 3 months later. Plasma NT proBNP was assessed before implantation and after 3 months. At baseline, RVEF was impaired (≤35%) in 14 patients, preserved (>35%) in 22. At 3 months, RVEF improved during rest and exercise (P = .02) in patients with impaired RV function, while remaining unchanged in patients with preserved RV function. Rest and exercise RV dyssynchrony decreased in both groups at follow-up (P < .05). A similar mid-term improvement in left ventricular (LV) function and NT-proBNP was observed in patients with impaired and preserved RVEF. In the former, the decrease in NT-proBNP correlated with the improvements both in LV and RV dyssynchrony and functions.
Conclusion: CRT may improve RV performance, during rest and exercise, and neurohormonal response in heart failure patients with nonischemic dilated cardiomyopathy and baseline RV dysfunction. RV dysfunction should not be considered per se a primary criterion for excluding candidacy to CRT.