title: The incidence of prebypass dysrhythmias in patients undergoing coronary artery surgery.
abstract: The incidence of dysrhythmias during the prebypass period of coronary artery surgery has not been accurately reported. Using Holter monitoring of the electrocardiogram, this study was undertaken to determine the incidence of dysrhythmias and ischemia and their relationship to specific events during the prebypass period. The role of preoperative calcium entry blockers (CEB), beta-adrenergic blockers (BB), or both on the incidence of dysrhythmias and ischemia was also studied. One hundred thirty-eight patients were premedicated with morphine, scopolamine, and diazepam. Anesthesia was induced with fentanyl or sufentanil followed by either pancuronium or vecuronium and maintained with sufentanil or enflurane. All 138 patients experienced a dysrhythmia during the prebypass period. Seventy-five percent of the patients had at least one episode of a supraventricular dysrhythmia (SVD), 39% had a sinus bradycardia, and 20% had a conduction abnormality. Ninety-two percent of the patients had premature ventricular contractions (PVC) and, surprisingly, 76% had non-sustained ventricular tachycardia. One patient developed ventricular fibrillation and one had ventricular tachycardia. The peak incidence of dysrhythmias occurred at insertion of the pulmonary artery (PA) catheter and at aortic dissection. The incidence of prebypass ischemia was 18%, but these patients did not have a higher incidence of ventricular dysrhythmias. Preoperative CEBs and BBs did not influence the incidence of ischemia or dysrhythmias with the exception of SVD; there was a significantly lower incidence at PA catheterization in patients taking CEBs preoperatively (P < .05). It can be concluded that dysrhythmias are very common during the prebypass period. The low rate of progression to life-threatening dysrhythmias may be related to the fact that the majority occurred during mechanical stimulation and that patients were chronically taking CEBs and/or BBs preoperatively.
authors.affiliation: Department of Anaesthesia, Royal Victoria Hospital and McGill University, Montreal, Quebec, Canada.
authors.forename: W F
authors.initials: WF
authors.lastname: Casey
authors.forename: J E
authors.initials: JE
authors.lastname: Wynands
authors.forename: J G
authors.initials: JG
authors.lastname: Ramsay
authors.forename: J P
authors.initials: JP
authors.lastname: O'Connor
authors.forename: C E
authors.initials: CE
authors.lastname: Smith
authors.forename: F E
authors.initials: FE
authors.lastname: Ralley
authors.forename: M H
authors.initials: MH
authors.lastname: Sami
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000009:adverse effects; D000704:Analysis of Variance; D000758:Anesthesia / Q000379:methods; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000453:epidemiology; D001919:Bradycardia / Q000175:diagnosis / Q000453:epidemiology; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000009:adverse effects; D002315:Cardiopulmonary Bypass; D002407:Catheterization, Swan-Ganz / Q000009:adverse effects / Q000187:drug effects; D003331:Coronary Vessels / Q000601:surgery*; D003975:Diazepam / Q000008:administration & dosage; D015716:Electrocardiography, Ambulatory / Q000379:methods; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology*; D011300:Preoperative Care / Q000379:methods*; D013610:Tachycardia / Q000175:diagnosis / Q000453:epidemiology; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000453:epidemiology; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D003975:Diazepam