A cyanotic baby boy was given a diagnosis of single right ventricle, double outlet right ventricle, hypoplastic aortic arch, mitral atresia, atrial septal defect and pulmonary-ductus-descending aorta trunk. On day 4, extended aortic arch anastomosis and pulmonary artery banding were undertaken. At age 70 days, severe cyanosis and respiratory distress appeared and advanced rapidly. Angiography revealed critical subaortic stenosis and pulmonary hypertension, and the patient required urgent Damus-Kaye-Stansel anastomosis with concomitant right modified Blalock-Taussig shunt. Patients with single ventricle and hypoplastic aortic arch are a high-risk subgroup of progressive subaortic stenosis after initial pulmonary artery banding, and therefore need careful observation and may require early relief of subaortic stenosis.

A 6-year-old boy who had been found to have hypertrophic obstructive cardiomyopathy presented with severely limited symptoms of heart failure due to progressive left ventricular outflow obstruction. Cardiac catheterization revealed the peak systolic pressure gradient of 87mmHg at left ventricular outflow, and systolic anterior motion of the anterior mitral leaflet with concomitant mitral regurgitation was observed by echocardiography. Transaortic septal myectomy was performed using transesophageal echocardiography guidance before, during and after surgery. Although the patient needed permanent pacemaker implantation for postoperative complete heart block, the procedure reduced the left ventricular outflow obstruction and relieved his symptoms.