What patients need an implantable cardioverter defibrillator?

Ventricular Arrhythm: Patients that have dangerous arrhythmias such as ventricular tachycardia or ventricular fibrillation are the usual candidates for an implanted cardio-verter defibrillator or icd.

VT/VF, certain other: In addition to preventing dangerous ventricular arrhythmias (which can cause sudden cardiac death) in people who have had these, in certain select cases cardioverter defibrillators have use for prevention of these heart rhythms in people who are at high risk for them. This can include certain cardiomyopathies, also some cases of congestive heart failure (combined with a biventricular pacemaker).