Independent contribution of electrocardiographic abnormalities to risk of death from coronary heart disease, cardiovascular diseases and all causes. Findings of three Chicago epidemiologic studies.

The importance of major and minor ECG abnormalities at baseline for subsequent risk of death from coronary heart disease, cardiovascular diseases and all causes was analyzed for middle-aged white men from the Chicago Peoples Gas Company, Chicago Western Electric Company and Chicago Heart Association Detection Project in Industry studies. Univariate analysis showed that in all three studies, men with major ECG abnormalities had death rates considerably higher than those with normal ECGs. When baseline age, diastolic pressure, serum cholesterol, relative weight and number of cigarettes per day were taken into consideration in multivariate analysis, ECG abnormalities retained significant relationship to the three death end points. Findings from the Chicago Western Electric Company and Chicago Heart Association studies showed independent relationship between minor ECG abnormalities and the three death end points. In the Chicago Peoples Gas Company (20-year follow-up) and in the Chicago Western Electric Company (17-year follow-up), when the deaths were divided into those that occurred within the first 10 years of follow-up and those that occurred more than 10 years after entry, the association between ECG abnormalities and mortality held for both the first and second decades of follow-up. Overall, findings from this study demonstrate an independent relationship between ECG abnormalities and death from coronary heart disease, cardiovascular disease and all causes.