Occlusion of the outflow tract in either the LEFT VENTRICLE or the RIGHT VENTRICLE of the heart. This may result from CONGENITAL HEART DEFECTS, predisposing heart diseases, complications of surgery, or HEART NEOPLASMS.

Synonyms: Ventricular Outflow Obstruction, Left, Left Ventricular Outflow Obstruction, Obstruction, Ventricular Outflow, Right Ventricular Outflow Obstruction, Outflow Obstruction, Left Ventricular, Outflow Obstructions, Ventricular, Ventricular Outflow Obstruction, Outflow Obstruction, Right Ventricular, Obstructions, Ventricular Outflow, Outflow Obstruction, Ventricular, Ventricular Outflow Obstructions, Ventricular Outflow Obstruction, Right