Reliability and Efficacy of Metoprolol and Diltiazem in Patients Having Mild to Moderate Mitral Stenosis with Sinus Rhythm

The authors evaluated the effects of beta blockers (metoprolol) and calcium channel blockers (diltiazem) in patients having mild to moderate mitral stenosis (MS) with sinus rhythm. Eighty patients with a complaint of dyspnea with diagnosed MS were included in this study. Patients were randomized into metoprolol and diltiazem groups. The first group received oral diltiazem treatment for 3 months following an IV dose of 25 mg diltiazem. The second group received oral metoprolol for 3 months following an IV dose of 5 mg metoprolol. All patients performed a treadmill exercise test at the beginning of and after 3 months of treatment. Transthoracic echocardiographic studies were also performed following the IV drug administration and after 3 months of treatment. In addition, oxygen uptakes of patients were measured before and after the stress and after 3 months of treatment. Decreases in peak gradient (PG) and mean transmitral gradient (MG) were observed in the metoprolol group after IV and oral metoprolol treatment. A prolongation of exercise time in treadmill exercise test (TET) and a decrease in the maximum heart rate after oral metoprolol treatment were noted. Eighteen patients in the metoprolol group had benefited symptomatically from this treatment and complaints of dyspnea were alleviated, whereas no symptomatic relief was seen in the diltiazem group. No significant prolongation was observed in effort times (p>0.05) of the diltiazem group. Transmitral gradients measured via echocardiographic examination did not change (p>0.05). With respect to oxygen uptake rates, a statistically significant decrease was determined in the metoprolol group, whereas no difference was found in diltiazem group. The authors conclude that metoprolol may be useful in patients with MS and can provide symptomatic relief. They did not observe any beneficial effect of diltiazem in these patients.