The value of the electrocardiogram in risk assessment in primary prevention: experience from the West of Scotland Coronary Prevention Study.

Electrocardiograms (ECGs) were recorded at baseline, annually thereafter, and at run-out in the West of Scotland Coronary Prevention Study to which 6595 men aged from 45 to 65 years on entry were recruited. The baseline ECGs were analyzed with respect to (a) the primary end point of the study, namely, fatal or nonfatal myocardial infarction (MI) and (b) all-cause mortality. In addition, incident MIs were reviewed to determine those detected by ECG only. Heart rate, indexed left ventricular mass, frontal T axis, and T amplitude in lead I were all significantly predictive with respect to the primary end point in a multivariate analysis. With respect to all-cause mortality, minor ST-T changes, 10-second heart rate variability, and frontal T axis were similarly predictive. Of 355 incident MIs, 47.3% were silent or unrecognized and detected by ECG only. A simple ECG-based risk prediction equation for fatal and nonfatal MI is introduced.