Influence of D,L-Sotalol on Baroreflex Sensitivity Response to Posture Following Coronary Artery Bypass Graft Surgery in Men and Women

Abstract

Low baroreflex sensitivity (BRS) following coronary artery bypass graft (CABG) surgery increases the risk of sympathetically mediated cardiac arrhythmias. To reduce this risk, d,l-sotalol, a nonselective β-adrenergic receptor antagonist (Class II) and an antiarrhythmic (Class III), is prescribed postoperatively. However, its effect on BRS has not been reported. The purpose of this study was to characterize the influence of d,l-sotalol on BRS measures in supine and standing postures 4 days following CABG surgery. BRS was measured in 27 men and 10 women receiving d,l-sotalol and compared with archival data for 21 men and 10 women obtained prior to the routine administration of d,l-sotalol. In the latter (control) group, 61% had BRS of less than 3 ms/mmHg in the supine posture and 74% in the standing posture compared to 42% with less than 3 ms/mmHg in the supine posture and 65% in the standing posture in the d,l-sotalol group. Men in the d,l-sotalol group showed higher R-R interval and BRS in both supine and standing postures compared with controls. Women in the d,l-sotalol group had higher R-R interval in the supine posture. The higher BRS in men not only reduces the risk of arrhythmias after CABG surgery but may also allow a more rapid circulatory response to the standing posture, thereby decreasing the risk of syncope.