The nature and prevalence of the abnormal exercise electrocardiogram in mitral valve prolapse

Abstract

The maximal treadmill exercise tests in 43 subjects with mitral valve prolapse were retrospectively examined and compared to those of 24 consecutive patients with abnormal maximal treadmill tests and arteriographic evidence of obstructive coronary artery disease and 21 consecutive patients with abnormal treadmill tests with evidence of neither mitral valve prolapse nor coronary artery disease at catheterization. Twelve of 43 (28%) patients with mitral valve prolapse had greater than 0.1 mv. of flat or downsloping ST depression during or following treadmill exercise. Of these 12 patients, seven (58%) were found to have the pattern of abnormal treadmill test previously described as indicative of “vasoregulatory abnormalities”; four patients satisfied the diagnostic criteria for acoustically silent mitral valve prolapse, and only one had clinical or angiographic evidence of mitral regurgitation. The finding of the “vasoregulatory” pattern of abnormal ECG response was significantly less common in the groups with abnormal treadmill tests and coronary disease and with neither coronary disease nor mitral valve prolapse (p < .0025). We conclude that the finding of an abnormal treadmill test, particularly of the type associated with “vasoregulatory abnormalities,” should lead to the suspicion of mitral valve prolapse, even in the absence of symptoms and typical auscultatory abnormalities.