Ventricular arrhythmias in patients undergoing noncardiac surgery. The Study of Perioperative Ischemia Research Group

Abstract

Objective: To determine the incidence, clinical predictors and prognostic importance of perioperative ventricular arrhythmias.

Design: Prospective cohort study (Study of Perioperative Ischemia).

Setting: University-affiliated Department of Veterans Affairs Medical Center, San Francisco, Calif.

Subjects: A consecutive sample of 230 male patients, with known coronary artery disease (46%) or at high risk of coronary artery disease (54%), undergoing major noncardiac surgical procedures.

Measurements: We recorded cardiac rhythm throughout the preoperative (mean = 21 hours), intraoperative (mean = 6 hours), and postoperative (mean = 38 hours) periods using continuous ambulatory electrocardiographic monitoring. Adverse cardiac outcomes were noted by physicians blinded to information about arrhythmias.

Main results: Frequent or major ventricular arrhythmias (greater than 30 ventricular ectopic beats per hour, ventricular tachycardia) occurred in 44% of our patients: 21% preoperatively, 16% intraoperatively, and 36% postoperatively. Compared with the preoperative baseline, the severity of arrhythmia increased in only 2% of patients intraoperatively but in 10% postoperatively. Preoperative ventricular arrhythmias were more common in smokers (odds ratio [OR], 4.1; 95% confidence interval [CI], 1.2 to 15.0), those with a history of congestive heart failure (OR, 4.1; 95% CI, 1.9 to 9.0), and those with electrocardiographic evidence of myocardial ischemia (OR, 2.2; 95% CI, 1.1 to 4.7). Preoperative arrhythmias were associated with the occurrence of intraoperative and postoperative arrhythmias (OR, 7.3; 95% CI, 3.3 to 16.0, and OR, 6.4; 95% CI, 2.7 to 15.0, respectively). Nonfatal myocardial infarction or cardiac death occurred in nine men; these outcomes were not significantly more frequent in those with prior perioperative arrhythmias, albeit with wide CIs (OR, 1.6; 95% CI, 0.4 to 6.2).

Conclusion: Almost half of all high-risk patients undergoing noncardiac surgery have frequent ventricular ectopic beats or nonsustained ventricular tachycardia. Our results suggest that these arrhythmias, when they occur without other signs or symptoms of myocardial infarction, may not require aggressive monitoring or treatment during the perioperative period.