Effect of ivabradine vs atenolol on heart rate and effort tolerance in patients with mild to moderate mitral stenosis and normal sinus rhythm.

BACKGROUND: Patients with mitral stenosis become symptomatic at a higher heart rate. We studied the comparative efficacy of heart rate control with ivabradine or atenolol and its effect on effort tolerance in patients with mild-moderate mitral stenosis in normal sinus rhythm.

METHODS AND RESULTS: Fifty patients with mild-moderate mitral stenosis in sinus rhythm were randomized to receive ivabradine or atenolol for 4 weeks each in an open-label, randomized, crossover design trial. A 24-hour Holter and treadmill test was performed at baseline and after each active treatment period. In the first treatment period, 23 patients were allocated to ivabradine (22 analyzed), and 27 were allocated to atenolol (26 analyzed). In the second period, all 48 patients were analyzed. Ivabradine increased the mean total exercise time to 500.7 seconds (SD 99.7) from a baseline of 410.3 seconds (SD 115.4), and atenolol increased it to 463.7 seconds (SD 113.1). The point estimate (absolute difference between ivabradine and atenolol) was 35.27 seconds (95% CI 15.24-55.20; P = .0009). The point estimate for decrease in the maximum exercise heart rate and mean heart rate were 7.64/min (95% CI 0.37-15.9; P = .04) and 5.61/min (95% CI 2.51-8.71; P = .0007), respectively.

CONCLUSIONS: Ivabradine is more effective than atenolol for effort related symptoms in patients with mild-moderate mitral stenosis and normal sinus rhythm.