Predicting of postoperative cardiac events using ambulatory ECG monitoring prior to abdominal aortic surgery.

Objectives: The purpose of this study was to estimate the value of preoperative electrocardiographic (ECG) monitoring in predicting postoperative cardiac events in patients undergoing abdominal aortic surgery.

Design: A prospective open study.

Setting: University Hospital.

Materials: One hundred consecutive patients were studied before aortic or aortofemoral surgery by ambulatory ECG monitoring for 24 hours.

Chief Outcome Measures: An ischaemic episode by ECG criteria was defined as a > or = 1 mm horizontal or downsloping ST segment depression measured 60 msec after the J point and persisting for at least 40 sec.

Main Results: Twenty-four patients had preoperative ambulatory ischaemia. Twenty patients had postoperative cardiac events including three with fatal myocardial infarction, one with a nonfatal infarction, eight with unstable angina, three with pulmonary oedema and five with atrial fibrillation. Sixteen out of 24 (67%) patients with ambulatory ischaemia had postoperative cardiac events (p < 0.01). Only four events occurred among 76 patients without ischaemia (p < 0.005). The sensitivity of ambulatory ischaemia predicting cardiac events was 80% with a specificity of 90%, the predictive value of ischaemia was 67% and the predictive value of a negative result was 95%.

Conclusions: Preoperative ECG monitoring for myocardial ischaemia could non-invasively identify patients at high risk for postoperative cardiac morbidity and mortality after vascular surgery.