Improved Right Ventricular Systolic Function After Cardiac Resynchronization Therapy in Patients With Heart Failure

Abstract

Background Since the introduction of cardiac resynchronization therapy (CRT) to improve left ventricular function, the effect of CRT on the right ventricle in patients with heart failure has not been well described. Methods We evaluated the effect of CRT on right ventricular systolic function in 20 patients (80% men; mean [SD] age, 58.5 [9.8] y) with cardiomyopathy and right ventricular systolic dysfunction (New York Heart Association class III or IV, left ventricular ejection fraction ≤35%, and QRS interval ≥120 ms). The median follow-up time was 15 months. Right ventricular systolic function, defined as a tricuspid annular plane systolic excursion (TAPSE) index of 16 mm or less, was evaluated in patients before and after CRT. Results Twelve (60%) patients had ischemic cardiomyopathy, and 12 (60%) patients had left bundle branch block detected using surface electrocardiogram. The mean (SD) QRS duration was 160.5 (24.4) ms. From before CRT to the time of follow-up after CRT, the mean (SD) ejection fraction increased significantly from 22.5% (5.6%) to 29.4% (7.4%) (P < .001). The mean (SD) TAPSE index also increased significantly from 13.70 (1.78) mm to 16.50 (4.77) mm (P = .018). Eleven (55%) patients showed improved right ventricular systolic function (TAPSE ≥16 mm) after CRT. Patients with a favorable right ventricular response to CRT were significantly older (64.6 [8.2] y vs 53.6 [8.4] y, respectively) and more likely to have nonischemic origin of cardiomyopathy than were patients with unimproved right ventricular function (66.7% vs 18.2%, respectively). Conclusion Our findings indicate that CRT is associated with improved right ventricular systolic function in patients with heart failure and right ventricular systolic dysfunction. Patients with nonischemic heart disease more often show improved right ventricular function after CRT.