ECG changes after non-cardiac surgery: a prospective observational study in intermediate-high risk patients

BACKGROUND: Efforts to mitigate the risk for perioperative cardiac events focus on both patient's and operation's risk and often include a preprocedural electrocardiogram (ECG). The merits of postprocedural ECG for detection of occult cardiac events occurring during surgery are unknown. We aim to explore the incidence of pre, and new postprocedural ECG pathologies in an intermediate-high risk population undergoing non-cardiac surgery. METHODS: This single-center, prospective, observational study, included patients older than 18 years with at least two cardiovascular risk factors who were scheduled for non-cardiac surgery. All patients had pre, and postprocedural ECG. The ECG was analyzed and coded according to the Minnesota criteria. A multivariable logistic regression analysis was performed for indices associated with new postoperative ECG pathologies. RESULTS: A total of 217 patients were enrolled. Preoperative pathologic ECG changes were recorded in 62.2% of the patients. Postoperatively, new ECG pathologies were documented in 49.8% of patients, most commonly T-wave changes (36.4% of changes). Pathologic ECG changes at baseline (OR 3.15, 95% CI 1.61-6.17; P<0.01), diabetes (OR 1.93, 95% CI 1.02-3.64; P=0.04), history of ischemic heart disease (OR 2.14, 95% CI 1.03-4.47; P=0.04), higher volumes of fluid replacement (OR 1.70, 95% CI 1.10-2.61; P=0.01) and higher levels of preoperative hemoglobin (OR 1.24, 95% CI 1.04-1.47; P=0.01) were all independently associated with postoperative ECG changes. CONCLUSIONS: Pre-, but most importantly, postoperative ECG changes are common in intermediate-high risk surgical patients. Postoperative ECG may be valuable to disclose silent cardiovascular events that occurred during surgery.