Sudden cardiac death claims 400,000 to 450,000 lives annually. It is believed that sudden cardiac death results predominantly from ventricular fibrillation or sustained ventricular tachycardia that deteriorates into ventricular fibrillation. Conventional treatments for patients who suffer from ventricular arrhythmias have been limited to antiarrhythmic drugs or surgery. These treatments have proved ineffective to a portion of arrhythmia sufferers. The implantable cardioverter defibrillator offers hope to a segment of ventricular arrhythmia sufferers whose disease is resistant to conventional therapies.