Objectives: Preoperative electrocardiograms (ECGs) are routinely performed on older patients before surgery. Whether patients with abnormalities on preoperative ECGs have an increased likelihood of developing postoperative cardiac complications is unknown. This study was designed to determine whether abnormalities on preoperative ECGs were predictive of postoperative cardiac complications.
Design: Prospective observational study.
Setting: One of the teaching hospitals of the University of California, San Francisco, Medical Center.
Participants: Five hundred thirteen patients aged 70 and older undergoing noncardiac surgery.
Measurements: Preoperative ECGs were analyzed using the Minnesota Codes. Predefined preoperative risk factors and in-hospital postoperative cardiac complications were measured. The association between ECG abnormalities and postoperative cardiac complications was determined by multivariate logistic regression after controlling for clinical covariates. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported.
Results: Three hundred eighty-six of 513 patients (75.2%) had at least one abnormality on their preoperative ECGs. On multivariate analysis, the predictors of postoperative cardiac complications included American Society of Anesthesiologists physical status classification of 3 or greater (OR = 2.5, 95%CI = 1.28-4.89, P = .007) and a history of congestive heart failure (OR = 2.1, 95% CI = 1.1-5.1, P = .034). The presence of abnormalities on preoperative ECGs was not associated with an increased risk of postoperative cardiac complications (OR = 0.63, 95% CI = 0.28-1.40, P = .26).
Conclusion: Abnormalities on preoperative ECGs are common but are of limited value in predicting postoperative cardiac complications in older patients undergoing noncardiac surgery. These results suggest that obtaining preoperative ECGs based on an age cutoff alone may not be indicated, because ECG abnormalities in older people are prevalent but nonspecific and less useful than the presence and severity of comorbidities in predicting postoperative cardiac complications.