INTERACTIVE EFFECTS OF ST-T WAVE ABNORMALITIES ON SURVIVAL OF PATIENTS WITH CORONARY-ARTERY DISEASE

Previous studies have documented a reduced survival time in patients with an electrocardiographic (ECG) ST-T wave abnormality. This study was designed to determine the clinical, hemodynamic and angiographic correlates of this observation. Data from 9,731 patients undergoing cardiac catheterization from 1976 through 1986 were analyzed; 5,531 had severe (> 70%) obstruction of at least one major coronary artery, 1,706 had mild (10 to 69%) obstruction and 2,494 had no obstruction. Of the patients with severe obstruction, 2,536 were treated medically and 2,995 were treated by surgical revascularization. Patients with an ST-T abnormality had more clinical risk factors (including older age and greater prevalence of diabetes mellitus, hypertension and prior myocardial infarction) and greater left ventricular dysfunction (including higher end-diastolic pressure and ventricular volume, reduced ejection fraction and greater prevalence of contraction abnormality) than did those without this ECG pattern. Survival time was significantly (p < 0.01) reduced in subsets of patients with an ST-T abnormality and with severe or mild coronary artery disease; in those without coronary disease, ST-T changes did not correlate with reduced survival. Stepwise regression analysis was applied to each group to determine the independent predictors of 5-year survival. In patients with severe disease or no disease, an ST-T abnormality was not chosen as an independent predictor of 5-year survival; in the group with mild disease, ST-T changes were an independent predictor of reduced survival. Thus, the independent impact of an ST-T abnormality on survival is dependent on the severity of underlying coronary artery disease.