Failure of oral atenolol and verapamil to increase the capacity and duration of exercise in patients in sinus rhythm with mitral stenosis

A comparative study of ivabradine and atenolol in patients with moderate mitral stenosis in sinus rhythm

BACKGROUND

Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to examine whether ivabradine was superior to atenolol for achieving higher exercise capacity in patients with moderate mitral stenosis in sinus rhythm. We also evaluated their effects on left ventricular myocardial performance index (MPI).

METHODS AND RESULTS

Eighty-two patients with moderate mitral stenosis in sinus rhythm were randomized to receive ivabradine (n=42) 5mg twice daily or atenolol (n=40) 50mg daily for 6 weeks. Transthoracic echocardiography and treadmill test were performed at baseline and after completion of 6 weeks of treatment. Mean total exercise duration in seconds markedly improved in both study groups at 6 weeks (298.57±99.05s vs. 349.12±103.53s; p=0.0001 in ivabradine group, 290.90±92.42s vs. 339.90±99.84s; p=0.0001 in atenolol group). On head-to-head comparison, there was no significant change in improvement of exercise time between ivabradine and atenolol group (p=0.847). Left ventricular MPI did not show any significant change from baseline and at 6 weeks in both drug groups (49.8%±8% vs. 48.3%±7% in ivabradine group, 52.9%±10% vs. 50.9%±10% in atenolol groups; p=0.602).

CONCLUSION

Ivabradine or atenolol can be used for heart rate control in patients with moderate mitral stenosis in sinus rhythm. Ivabradine is not superior to atenolol for controlling heart rate or exercise capacity. Left ventricular MPI was unaffected by either of the drugs.

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 i.v. dose of 25 mg diltiazem. The second group received oral metoprolol for 3 months following an i.v. 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 i.v. 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 i.v. 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.

Value of exercise Doppler-echocardiography in patients with mitral stenosis

The value of exercise Doppler-echocardiography was studied in 60 patients with mitral valve stenosis. Patients were divided in three groups. In patients with a mitral valve area of more than 1.4 cm2, maximal and mean diastolic gradient over the mitral valve increased from 13.2 +/- 3.6 to 18.4 +/- 5.4 and from 5.2 +/- 1.9 to 8.8 +/- 3.0 mmHg, respectively. In patients with a mitral valve area in between 1.0 and 1.4 cm2, maximal and mean gradient increased from 19.0 +/- 8.0 to 28.1 +/- 8.9 and from 8.8 +/- 4.9 to 14.8 +/- 6.4 mmHg, respectively. In patients with a mitral valve area of less than 1 cm2, the maximal gradient increased from 21.5 +/- 5.8 to 34.2 +/- 8.7 and mean gradient increased from 11.8 +/- 4.1 to 20.3 +/- 5.8 mmHg. Mean tricuspid regurgitation velocity increased from 2.9 +/- 0.5 m/s to 3.6 +/- 0.5 m/s, indicating increase in right ventricular to right atrial pressure difference from 34 mmHg to 52 mmHg. We conclude that exercise during the Doppler-echocardiographic evaluation provides additional information about the hemodynamic significance of mitral stenosis and can therefore be of value in decision making.