The patient was a 13-year-old male with chief complaints of exertional chest pain and dyspnea. Cardiac murmur was suspected in a medical checkup at 1 month old, at which time he was diagnosed with subvalvular aortic stenosis. He had subsequently been under follow-up observation at a nearby hospital for subvalvular aortic stenosis. He was admitted to our department for surgery due to aggravation of symptoms that had occurred over the previous year. Transthoracic echocardiography after admission showed an abnormal structure in the subvalvular aortic area, and the maximum pressure gradient between the left ventricle and aortic valve was 84 mmHg. The preoperative valve area was 0.71 cm(2), as measured by the Doppler method. Measurement of valve area by the trace method was difficult. Transesophageal echocardiography (TEE) showed a septum-like structure extending from the ventricular septum in the subvalvular area. On 3D TEE, the valve areas in the systolic and diastolic phases were 0.86 and 0.49 cm(2), respectively. Postoperative echocardiography showed resection of the structure in the subvalvular area, and the postoperative course was favorable.
Keywords: Fibromuscular subvalvular aortic stenosis; Three-dimensional transesophageal echocardiography.