Spectrum of ST amplitude: athletes and an ambulatory clinical population.

BACKGROUND AND PURPOSE: To augment data guiding thresholds for myocardial ischemia and cardiac risk, we studied resting ST amplitude in ambulatory patients and collegiate athletes.

METHODS: We analyzed 4041 ECGs from ambulatory visits at the Veterans Affairs in Palo Alto, California from 1997 to 1999 and 1114 screening ECGs from Stanford University athletes in 2007-2008. Using the PR interval as the isoelectric line and >95μV and<-45μV (visually equivalent to 1mm and 0.5mm) to define ST elevation and depression, ST amplitude was measured at QRS-end.

RESULTS: ST elevation was most prevalent in males, African Americans, and athletes (87% of male athletes in anterior leads). ST depression was rare in athletes and, among patients, associated with time to cardiovascular death in lateral leads (age-adjusted HR of 1.9, p<0.001).

CONCLUSIONS: ST amplitude differs by gender, age, race, and athletic status, which should be considered when developing guidelines for ECG interpretation.