The QRS complex represents ventricular depolarization. Ventricular rhythms comprise impulses generated from the ventricles with a prolonged QRS complex (> 120 milliseconds). Some supraventricular arrhythmias may also have a prolonged QRS complex, but only if there is a disturbance in the conduction of supraventricular impulses to the ventricles. 

This section describes five ventricular arrhythmias: premature ventricular complexes, ventricular tachycardia, ventricular fibrillation, idioventricular rhythms, and asystole.