Incidence
The prevalence of multiple defects in the muscular ventricular septum is low, occurring in less than one-fifth of patients in whom deficiency of the ventricular septum is the main finding, and in no more than 2% of those with co-existing lesions such as discordant ventriculo-arterial connections, tetralogy of Fallot, or atrioventricular septal defect.35,36