Arrhythmia

A condition in which an extra electrical pathway connects the atria (two upper chambers) and the ventricles (two lower chambers). It may cause a rapid heartbeat.

Ventricular fibrillation (VF) is a cause of cardiac arrest and sudden cardiac death. The ventricular muscle fibres contract randomly causing a complete failure of ventricular function. Most cases of ventricular fibrillation occur in patients with pre-existing known heart disease but the precise nature of the underlying cause of VF is not currently known

A defect (hole) in the ventricular septum which allows blood to shunt from one ventricle to the other.