1024-76 Beta-Adrenergic Blockade in Patients with Moderate Mitral Stenosis

Abstract

β -blocker therapy remains controversial in patients with mitral stenosis. In this randomized, double-blinded, crossover, placebo-controlled study, the effects of atenolol (50 and 100 mg/day) were assessed in 15 patients (age = 46 ± 11 yrs) with moderate mitral stenosis (mitral valve area = 1.0 ± 0.4 cm 2 ; NYHA class II-III) at rest (R) and during upright bicycle ergometry (E). Doppler-echocardiography was employed to compare heart rate (HR), cardiac (CI) and stroke volume (SVI) indices, diastolic filling period (DFP), and peak and mean (Mn Grad) transmitral gradients; a metabolic cart was used to obtain maximum VO 2 , VCO 2 and anaerobic threshold (AT). β -blockade therapy did not improve exercise time, extemal work, max VO 2 or AT. During exercise, max V02 and CI decreased (p < 0.05) > 11% and > 20%, respectively, with atenolol. Thefollowing hemodynamic data are presented as mean ± sd: Placebo Atenolol 50 mg 100 mg HR R 76 ± 13 60 ± 11 * 58 ± 13 * (bpm) E 144 ± 15 112± 23 * 103 ± 21 * DFP R 431 ± 97 604 ± 148 * 629 ± 175 * (msec) E 208 ± 35 277 ± 90 * 300 ± 95 * SVI R 22 ± 7 22 ± 6 26 ± 8 (ml/m 2 ) E 21 ± 10 22 ± 10 26 ± 9 Mn Grad R 5 ± 4 4 ± 3 4 ± 2 (mmHg) E 20 ± 8 17 ± 8 15 ± 8 * * p < 0.05 Placebo vs Atenolol Although HR and Mn Grad decreased and DFP increased with atenolol, SVI changed little compared with placebo. The data suggest that in spite of lower transvalvular pressure gradients little benefit in exercise performance is achieved with β -blocker therapy in patients with moderately severe mitral stenosis.