Electroconvulsive therapy-induced cardiac arrhythmias during anesthesia with methohexital, thiamylal, or thiopental sodium.

Author(s): Mokriski BK, Nagle SE, Papuchis GC, Cohen SM, Waxman GJ

Affiliation(s): Department of Anesthesiology, University of Maryland School of Medicine, Baltimore 21201.

Publication date & source: 1992-05, J Clin Anesth., 4(3):208-12.

Publication type: Clinical Trial; Randomized Controlled Trial

STUDY OBJECTIVE: To determine the frequency of electroconvulsive therapy (ECT)-induced arrhythmias under methohexital, thiamylal, or thiopental sodium anesthesia with and without atropine premedication. DESIGN: A randomized, double-blind study, placebo-controlled for atropine. SETTING: The inpatient psychiatric unit at a university medical center. PATIENTS: Forty-nine patients scheduled for ECT. INTERVENTIONS: Atropine 0.6 mg intravenously (IV) or an equal volume of normal saline IV was given before IV induction of anesthesia with methohexital 0.5 to 1.0 mg/kg, thiamylal 1.5 to 2.5 mg/kg, or thiopental sodium 1.5 to 2.5 mg/kg. MEASUREMENTS AND MAIN RESULTS: Single-lead electrocardiogram (ECG) recordings were made for 1 minute before induction, during induction of anesthesia, and for 5 minutes after the ECT stimulus. Each ECG was evaluated for arrhythmias and evidence of ischemia in a blinded fashion. Blood pressure and ECG evidence of ischemia did not differ among the groups. Seizure duration was significantly (p less than 0.05) prolonged by a mean of 5 seconds during methohexital anesthesia compared with thiopental sodium and thiamylal (47.6 +/- 18.6 seconds, 42.7 +/- 13.2 seconds, and 42.7 +/- 15.2 seconds, respectively). The frequency of sinus bradycardia was decreased (p less than 0.05) with methohexital (8%) compared with thiopental sodium (20%) and thiamylal (20%). The frequency of premature atrial contractions was decreased (p less than 0.05) with methohexital (43%) compared with thiamylal (61%) but not with thiopental sodium (57%). The frequency of premature ventricular contractions was decreased (p less than 0.05) with methohexital (27%) compared with thiopental sodium (44%) but not with thiamylal (40%). Atropine decreased the frequency of bradycardia (9% vs. 24%) and premature atrial contractions (47% vs. 61%) and increased the frequency of sinus tachycardia (88% vs. 75%). CONCLUSIONS: These data suggest that anesthesia for ECT therapy should be induced with methohexital to minimize the possibility of potentially life-threatening cardiac arrhythmias. Atropine premedication may further decrease the frequency of premature atrial contractions and bradycardia, while increasing the frequency of tachycardia.