Pseudo-false-positive exercise treadmill testing caused by systolic anterior motion of the anterior mitral valve leaflet.

Subendocardial ischemia as indicated by electrocardiography during exercise, in association with severe systolic anterior motion of the anterior mitral valve leaflet without left ventricular hypertrophy, has not been well described. We report the case of a 42-year-old man who presented with symptoms of exertional angina and 2-mm ST depression on treadmill electrocardiography but had a normal perfusion scan and coronary angiogram. Initially the negative angiographic results caused us to regard the treadmill results as false-positive. Subsequently, low-dose dobutamine echocardiography showed severe systolic anterior motion of the anterior mitral valve leaflet with a >144-mmHg left ventricular outflow tract gradient; we then recognized the original treadmill results to be pseudo-false-positive. Electrocardiographic changes in association with the above-described motion of the anterior mitral valve leaflet and increased left ventricular outflow tract gradient were verified by use of treadmill and supine bicycle stress echocardiography.