Hypertrophic obstructive cardiomyopathy causing severe right and left ventricular outflow tract obstruction.

An 18-year-old male patient presented with a 3-year history of exertional dyspnea, dizziness, and angina. Echocardiography showed advanced hypertrophy of the left ventricle (LV), right ventricle (RV) free wall, and interventricular septum. There were apparent muscular bundles especially at the level of the right ventricular outflow tract (RVOT). Maximal pressure gradients across the RVOT and left ventricular outflow tract (LVOT) were 141 mmHg and 66 mmHg, respectively. There was also grade 2 aortic regurgitation. Transesophageal echocardiography and cardiac magnetic resonance imaging confirmed these findings. Despite treatment with propranolol and cibenzoline, the patient remained symptomatic with unchanged pressure gradients. Corrective surgery including an extensive muscular resection of the RVOT, minimal resection of the LVOT, and interposition of a graft patch in the RVOT resulted in complete disappearance of the RVOT gradient and a significant decrease to 28 mmHg in the LVOT gradient. During a year follow-up, aortic valvular insufficiency remained clinically stable and the patient was asymptomatic. This is the first case of hypertrophic obstructive cardiomyopathy with predominant RVOT obstruction treated by myectomy and patch graft interpositioning.