Effect of Metoprolol Treatment on Pulmonary Venous Flow Pattern Studied by Transesophageal Pulsed Doppler Echocardiography in Mild to Moderate Mitral Stenosis in Sinus Rhythm

This study was conducted to evaluate the effect of metoprolol therapy on pulmonary venous flow pattern in patients with mild to modarete mitral stenosis in sinus rhythm. We studied 23 patients with isolated mild to moderate mitral stenosis (mitral valve area 1.6±0.3 cm2). All patients received metoprolol 100 mg once daily orally for 1 month. Pulsed wave Doppler transesophageal echocardiograpic examination of the pulmonary venous flow was performed at the beginning of the study and after 1 month of treatment. Peak systolic pulmonary venous flow (PVs) velocity, PVs velocity time integral (VTI), peak diastolic pulmonary venous flow (PVd) velocity, PVd-VTI, peak pulmonary venous atrial reversal flow (PVa) velocity, PVa-VTI, and PVa duration time were measured. Peak and mean transmitral gradient, pulmonary artery pressure, systolic and diastolic blood pressure, and heart rate, reduced significantly after metoprolol treatment. The pulmonary venous peak systolic velocity, and pulmonary venous atrial reversal flow velocity duration time increased significantly from 0.55 ± 0.19 m/s to 0.66 ± 0.12 m/s, p<0.05, and from 84 ± 27 to 11 2± 31 msec, p<0.01, respectively). Regarding VTI, PVs-VTI increased from 10.8±3.2 cm to 11.9±4.3 cm (p<0.01), PVd-VTI increased from 5.1± 2.4 cm to 5.4±2.5 cm (p<0.05), and PVa- VTI increased from 2.8±1.1 cm to 3.1±1.3 cm, p<0.05.
CONCLUSION
Metoprolol treatment increased pulmonary venous flow as an indicator of improved left atrial function in patients with mitral stenosis and sinus rhythm. These results may contribute to disclosing the underlying mechanisms of the favourable effects of beta blockade in mitral stenosis.