Age, sex, and the ST amplitude in health and disease.

Electrocardiograms (ECGs) from 1,338 apparently healthy adults were analyzed to calculate limits of normality of a variety of ECG measurements. A second set of ECGs from 503 healthy Chinese individuals was also available for comparison of selected normal ranges. It was found that the normal limits of the ST amplitude in healthy individuals decrease with increasing age and, in general terms, are lower in women than in men, particularly in the precordial leads. For example, the upper limit of normal ST amplitude in V3 in a 25-year-old man is 0.31mV but is only 0.11 mV in a woman of the same age. On the other hand, the age-dependent contribution to variation in the upper limit of normal of ST amplitude is effectively confined to men. The one exception to this appears to be the mean ST slope in V2, which decreases with increasing age in both men and women and is higher in the former compared to the latter. Recommended ECG related criteria, particularly in V1, for administration of thrombolytic therapy appear to be neither age nor sex dependent, which is a significant shortcoming given the foregoing information.