Mitral annular calcification (MAC) is frequently observed, but it rarely causes left ventricular outflow tract (LVOT) obstruction (LVOTO). An 83-year-old woman with hypertension, diabetes, and dyslipidemia was admitted to our hospital because of exertional dyspnea. She was diagnosed with hypertensive heart disease. Her symptoms were exacerbated by exertion, and she had no symptoms at rest. Transthoracic echocardiography showed massive posterior MAC, a sigmoid septum, and LVOTO, with a peak gradient of 15.4 mmHg at rest. Systolic anterior motion of the anterior mitral leaflet was not found. Moreover, the LVOT gradient in the stress condition was evaluated, and an increased LVOT gradient (47.3 mmHg) and chest discomfort was noted after 20 μg/kg/min of dobutamine was administered and the Valsalva maneuver was used. Hence, the patient was diagnosed with latent LVOTO. Interestingly, the distance between the septal wall, which was protruding into the left ventricular cavity, and the mitral valve coaptation, which was pushed up by the posterior MAC, had become closer, causing dynamic LVOTO. Since it is difficult to treat LVOTO with medication, ultimately, septal myectomy and mitral valve replacement were performed, which improved her symptoms. Evaluating the LVOT pressure gradient in stress condition is important in patients with MAC. <Learning objective: Mitral annular calcification (MAC) is commonly found in older people. However, it is not well known that MAC can cause left ventricular outflow tract obstruction (LVOTO). In the present case, massive posterior MAC was one of the factors that caused LVOTO. Left ventricular hypercontractility and a sigmoid septum were found to contribute to LVOTO, and stress echocardiography was useful for detecting the latent LVOTO. It is interesting that MAC can contribute to LVOTO in a stress condition.>.
Keywords: Hypertensive heart disease; Left ventricular outflow tract obstruction; Mitral annular calcification; Sigmoid septum; Stress echocardiography.