The orthogonal electrocardiogram as risk indicator for the prediction of myocardial infarction and/or cardiac death.

In a prospective study on Coronary Heart Disease (CHD) orthogonal electrocardiograms (Frank) were recorded annually for ten years from 1,444 asymptomatic, middle-aged males with a mean age of 57.4 +/- 10.6 years. Cases with overt or suspected CHD were excluded. The purpose of the study was to identify risk indicators in electrocardiograms and to compare them with other known risk factors used for prediction of acute CHD events such as myocardial infarction (MI) and/or cardiac death (CD). Such acute events occurred in 88 cases. Pre-event ECGs of these acute events were compared with all others without events, using logistic regression analysis. Identified ECG risk indicators were then compared with other known risk factors such as smoking, blood pressure, cholesterol, age, weight, etc. The predictive power of the ECG, derived mainly from the ST-T complex, exceeded all others by a wide margin. The amplitude of the first 1/8 of the ST-T complex in lead x (similar to V5-V6) together with relative body weight proved best when one pre-event record was available. Prediction improved when ECG changes between two pre-event recordings were included. Precision of measurements by computer appeared essential for improvements in CHD prediction.