A pilot study on the effects of carvedilol on right ventricular remodelling and exercise tolerance in patients with...

Patients with atrial repair for transposition of the great arteries and patients with congenitally corrected transposition have a right ventricle (RV) in the systemic position and they may develop RV dysfunction and exercise intolerance with advancing age. No data is available on the effect of carvedilol in patients with dysfunctional systemic RV.

We studied with cardiovascular magnetic resonance (CMR), cardiopulmonary exercise testing, and standard 12-leads electrocardiogram, 8 adults (median age 26 years, range 18-31) with chronic stable heart failure and systemic RV dysfunction (6 patients with atrial repair and 2 patients with congenitally corrected transposition). Assessment was done before and after 12 months of carvedilol administration. The initial dose was 3.125 mg twice daily, and the target dose was 25 mg twice a day.

Carvedilol administration was safe and the target dose was achieved in 5/8 (62%) patients. Right ventricular end-diastolic (119 ± 31 vs. 112 ± 28 ml/m², p=0.01) and end-systolic volumes decreased (79 ± 17 vs. 65 ± 14 ml/m², p=0.006), and RV ejection fraction improved (34 ± 6 vs. 42 ± 7%, p=0.004). Left ventricular ejection fraction increased (44 ± 8 vs. 49 ± 9%, p=0.01), suggesting a positive biventricular remodelling. Peak oxygen uptake did not change with carvedilol (26.8 ± 5.3 vs. 27.3 ± 5.7 ml O₂/Kg/min, p=0.58), whereas exercise duration increased (13.4 ± 2.6 vs. 17.3 ± 3.1 min, p=0.008).

In this small cohort, carvedilol administration was safe and it was associated with positive RV remodelling as well as improved exercise duration.