Acute myocardial ischemia associated with latent left ventricular outflow tract obstruction in the absence of left ventricular hypertrophy.

Left ventricular outflow tract obstruction (LVOTO) is a recognized feature in hypertrophic cardiomyopathy, but can occur in other clinical scenarios such as acute myocardial ischemia. In some patients, LVOTO may only be detectable with provocation testing such as exercise stress. Accurate and timely diagnosis, therefore, relies on recognizing an echocardiographic substrate in which LVOTO may occur, such as ventricular hypertrophy. The investigators describe two cases of latent LVOTO, presenting with acute myocardial ischemia in the absence of obstructive coronary artery disease, in which the diagnosis was delayed because of the absence of hypertrophy, or other recognizable substrate, on the resting echocardiographic study, but became evident during exercise echocardiography.