Beta blockade for patients of mitral stenosis in sinus rhythm

Twenty patients of isolated mitral stenosis in normal sinus rhythm (age 22 +/- 4 yrs) in whom symptoms of systemic and pulmonary congestion were controlled on diuretics were the subjects of the present study. The effects of addition of Metoprolol 50 mg po bid for 4 weeks on subjective and objective indices of exercise tolerance were evaluated. Metoprolol produced greater than 50% subjective improvement in 80% of these patients. The increase in time to dyspnoea and total work done on treadmill after 90-120 mins, and after 12 hrs of a dose of metoprolol, were both significant (p less than 0.01). In none of the patients, resting heart rate less than 50/mt, resting and exercise systolic BP less than 90 and less than 105 mmHg, respectively, or any important untoward effects were observed. Metoprolol's beneficial effects and safety can be judged in these patients at two hours after first dose in out patients clinic.