Effects of sibutramine on ventricular dimensions and heart valves in obese patients during weight reduction.

Background: Obesity enhances hemodynamic alterations that predispose to a subsequent increase in left ventricular (LV) wall stress leading to LV hypertrophy. In obese subjects, weight reduction regresses LV mass (LVM), regardless of blood pressure. Sibutramine can increase blood pressure and heart rate, which may attenuate the reductions in LVM associated with weight loss.
Methods: Outpatients (n = 184, age 18-65 y, body mass index > or =30 to <40 kg/m2) were randomly assigned to 6 months of once daily double-blind treatment with sibutramine 10 mg or 20 mg, or placebo. LV dimensions, status and function of the valves, weight loss, blood pressure, heart rate, and electrocardiogram were assessed.
Results: For end point data sets, the mean +/- SD LVM index (LVM/height) changes were -3.0 +/- 11.9 g/m for placebo (n = 56), -4.4 +/- 10.7 g/m for sibutramine 10 mg (n = 61), and -4.3 +/- 10.9 g/m for sibutramine 20 mg (n = 56). The reductions observed in the sibutramine groups were statistically significant compared with baseline (P <.01), but pairwise comparison results with placebo were not statistically significant. There was no difference in overall status of the cardiac valves. A statistically significant greater weight loss was found in patients on both doses of sibutramine compared with placebo (P <.001). No statistically significant differences between the groups were observed in respect to blood pressure and electrocardiographic intervals, but a statistically significant increase in pulse rate (7 beats/min) was noted for patients with sibutramine treatment.
Conclusion: A 6-month treatment with sibutramine does not affect ventricular dimensions, heart valves, and electrocardiogram variables.