Esmolol: safety and efficacy in postoperative cardiothoracic patients with supraventricular tachyarrhythmias.

Esmolol, an intravenous, ultrashort-acting beta-blocker, was studied for its ability to safely control supraventricular arrhythmias up to 24 hours in 15 postoperative cardiothoracic surgery patients with atrial fibrillation or flutter and rapid ventricular response. Esmolol obtained an initial therapeutic response in nine (60 percent) patients. Mean heart rate for the 15 patients was reduced from 139 +/- 12 beats/min before therapy to 106 +/- 21 beats/min during esmolol infusion (p less than 0.01). The mean time to a therapeutic response after initiation of therapy, using a multistep titration regimen (500 micrograms/kg/min loading infusions over one minute, prior to incremental titration steps from 50 to 300 micrograms/kg/min over 4 to 14 minutes), was 22 +/- 9 minutes, and therapy was continued for 17 +/- 9 hours in responders. Esmolol significantly lowered blood pressure in the group studied and resulted in mild supine or orthostatic hypotension in ten (67 percent) patients. Side effects, including hypotension (10/15 patients), gastrointestinal disturbances (2/15), and weakness or somnolence (6/15), were transient and were not associated with serious clinical sequelae. We conclude that esmolol is effective for rate control in a majority of postoperative cardiothoracic surgery patients with atrial fibrillation or flutter. Side effects, although mild, occur relatively frequently, limiting prolonged infusions and warranting close surveillance of patients.