Comparative evaluation of exercise ST response in healthy males and females. A computer study.

In order to evaluate both quantitatively and qualitatively exercise ST response in females, we have studied 232 healthy subjects (age range 35-59 years): 82 women (mean age 45.8 years) and 150 men (mean age 46.1 years). All subjects had performed a maximal treadmill exercise in 1976 and were followed up for 6 years in order to exclude the presence of subclinical coronary artery disease. Exercise ST segment responses were evaluated in a single bipolar lead (CB5) and were classified as 'positive' by visual interpretation when a 1.0-mm or greater 'ischemic' ST depression occurred. A computer system was employed to evaluate exercise ST changes quantitatively. The following ST parameters were evaluated: ST depression at R + 80 ms point (ST2); mean ST depression (STmean), and ST time-voltage integral (STarea). Computer analysis of resting ECG has shown lower ST voltages in females than in males. ST2, STarea, and STmean changes from basal to maximal exercise values were not significantly different in men and women. A similar prevalence of 'positive' responses in males and females was also found by ECG visual interpretation. In conclusion, our data show that in healthy subjects exercise ST segment response is comparable in males and females and indirectly suggest that the lower predictive value of exercise ECG in women is likely to be related to different coronary artery disease prevalence.