Effect of estrogen on exercise electrocardiograms in healthy postmenopausal women

Digoxin has been shown to produce a false-positive exercise electrocardiographic response (ST-segment depression) in about 25% of study subjects.1 Estrogen—which shares certain chemical similarities with digoxin including a steroid nucleus—has been implicated as a cause of a false-positive exercise electrocardiographic response.2 This finding was based on a retrospective study that was not adequately designed to address the causal role of estrogen in producing false-positive stress tests. Age, history of smoking, hypercholesterolemia, diabetes, hypertension, obesity, drug therapy, exercise duration, peak exercise heart rate and blood pressure, concomitant use of progesterone, and prior use of hormone replacement therapy were not predictive of a positive electrocardiographic response. [...]we have demonstrated that approximately 20% of postmenopausal women with a normal baseline stress echocardiogram will have a false-positive exercise electrocardiographic response to oral exogenous estrogen therapy.