What are the causes of double outlet right ventricle?

1. The hemodynamic changes in double outlet right ventricle mainly depend on the location and size of the ventricular septal defect, as well as the presence and severity of pulmonary artery stenosis. When the ventricular septal defect is located below the aortic valve without pulmonary artery stenosis, the left ventricular blood flow directly enters the aorta, while the right ventricular blood flow mainly enters the pulmonary artery, leading to increased pulmonary blood flow.

2. Clinically, it is similar to simple ventricular septal defect and pulmonary hypertension. When the ventricular septal defect is located below the pulmonary valve without pulmonary artery stenosis, the left ventricular blood mainly enters the pulmonary artery directly through the defect.

3. The right ventricular blood mainly enters the aorta, clinically resembling complete transposition of the great arteries and ventricular septal defect, including pulmonary congestion and severe cyanosis. If the ventricular septal defect is large, there is no obstacle to left ventricular blood flow, and the pressures in the left right and ventricles are equal. If the ventricular septal defect is small, left ventricular blood flow is obstructed, resulting in a pressure difference between the left and right ventricles, with the left ventricular pressure being higher than the right ventricular pressure. Regardless of the location and size of the ventricular septal defect, if there is pulmonary artery stenosis, it clinically resembles severe tetralogy of Fallot, pulmonary ischemia, and severe cyanosis.