Ventricular dysrhythmias in patients undergoing coronary artery bypass graft surgery: incidence, characteristics, and prognostic importance. Study of Perioperative Ischemia (SPI) Research Group.
To determine the incidence and characteristics of ventricular dysrhythmias (premature ventricular contractions greater than 30/min, ventricular tachycardia greater than or equal to 3 beats, and ventricular fibrillation) and whether a relationship exists between ventricular tachycardia and myocardial ischemia in patients undergoing coronary artery bypass graft surgery, we continuously monitored 50 patients for 10 perioperative days using two-lead electrocardiography. Electrocardiographic changes consistent with ischemia were defined as a reversible ST depression greater than or equal to 1.0 mm, or ST elevation greater than or equal to 2.0 mm from baseline, lasting at least 1 minute. Ventricular dysrhythmias developed in 10% of patients preoperatively and in 16% intraoperatively before bypass surgery. The highest incidence occurred postoperatively, with ventricular dysrhythmias developing in 66% of patients (22% to 44% of patients on any postoperative day 0 to 7). Premature ventricular contractions were greater than 30/hr in 6% of patients preoperatively, in 8% intraoperatively before bypass, and in 34% postoperatively (6% to 23% of patients on any postoperative day). Twenty-nine patients (58%) developed 76 verified episodes of greater than or equal to 3 beats of ventricular tachycardia. Ventricular tachycardia occurred in 6% of patients preoperatively (four episodes), in 8% of patients intraoperatively prior to bypass (four episodes), and 54% of patients postoperatively (5% to 21% on any postoperative day). No patient developed ventricular fibrillation. All postoperative ventricular tachycardia episodes (after tracheal extubation) were asymptomatic. Postoperatively, 48% of patients developed ischemia, compared with 12% preoperatively and 10% intraoperatively before bypass surgery. Only 5 of 68 (7%) postoperative ventricular tachycardia episodes occurred within 3 hours of an ischemia episode.(ABSTRACT TRUNCATED AT 250 WORDS)
Smith
R C
RC
Department of Anesthesia, University of California, San Francisco 94121.
Leung
J M
JM
Keith
F M
FM
Merrick
S
S
Mangano
D T
DT
D000328:Adult; D000368:Aged; D005117:Cardiac Complexes, Premature / Q000175:diagnosis / Q000453:epidemiology*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000150:complications / Q000453:epidemiology; D004562:Electrocardiography; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000175:diagnosis / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology*; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013610:Tachycardia / Q000175:diagnosis / Q000453:epidemiology*