1. A common congenital heart defect; an abnormal opening in the septum dividing the ventricles allows blood to pass directly from the left to the right ventricle; large openings may cause congestive heart failure
   "The newborn was diagnosed with a small ventricular septal defect that the doctors hoped would close on its own"

Derived forms: ventricular septal defects

Type of: septal defect

Part of: Fallot's syndrome, Fallot's tetralogy, tetralogy of Fallot

Encyclopedia: Ventricular septal defect