Objectives: We sought to analyze the value of infrequently measured parameters of the 12-lead electrocardiogram (ECG) in predicting cardiovascular events in women with suspected myocardial ischemia who were referred for cardiac catheterization.
Background: Routinely analyzed ECG parameters have low predictive value for cardiovascular events in women with preserved left ventricular function and suspected myocardial ischemia. The predictive value of ECG parameters for cardiovascular disease has not been fully determined.
Methods: Women enrolled in the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) study who had complete digital 12-lead ECG and quantitative angiography data were studied. Clinical and ECG predictors of cardiovascular disease events, defined as death, congestive heart failure, and non-fatal myocardial infarction, were determined.
Results: Of 143 women with ECG and angiographic data (mean age 59 +/- 13 years, left ventricular ejection fraction 64.1 +/- 8.6%), 13% had events during a mean follow-up period of 3.3 +/- 1.6 years. Independent predictors of event occurrences included a wider QRS-T angle (i.e., the spatial electrical angle between the QRS complex and the T-wave; p = 0.0005), wider QRS complex (p = 0.004), longer QTrr (i.e., age- and gender-adjusted QT interval; p = 0.0004), a more depressed ST-segment in precordial lead V5 (p = 0.0002), and a higher coronary artery disease severity score (p = 0.02).
Conclusions: Several 12-lead ECG parameters, such as the QRS-T angle and the QRS and QTrr duration, are predictive of future cardiovascular events in women with suspected myocardial ischemia.