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General principles of the implantable cardioverter-defibrillator

Leonard I Ganz, MD, FHRS, FACC
Section Editor
Brian Olshansky, MD
Deputy Editor
Brian C Downey, MD, FACC


Ventricular fibrillation (VF) is a common cause of sudden cardiac death (SCD) and is sometimes preceded by monomorphic or polymorphic ventricular tachycardia (VT). Although cardiopulmonary resuscitation, including chest compressions and assisted ventilation, can provide transient circulatory support for the patient with cardiac arrest, the only effective approach for terminating VF is electrical defibrillation. Success with external defibrillation led to the development of an implantable defibrillator in the mid-1960s. It was not until 1980 that the first automatic internal defibrillator was implanted in humans [1,2]. (See "Pathophysiology and etiology of sudden cardiac arrest".)

Since that time, there has been a dramatic increase in the use of the implantable cardioverter-defibrillator (ICD) to monitor for VT/VF and to provide prompt treatment. Because of its high success rate in terminating VT/VF rapidly, results of multiple clinical trials showing improvement in survival, ICD implantation is generally considered the first-line treatment option for the secondary prevention of SCD and for primary prevention in certain populations at high risk of SCD due to VT/VF. Alternatives to ICD implantation include antiarrhythmic drugs, ablative surgery, transcatheter ablation, and, in selected individuals, cardiac transplantation. (See "Sustained monomorphic ventricular tachycardia in patients with a prior myocardial infarction: Treatment and prognosis", section on 'Radiofrequency catheter ablation' and "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy" and "Pharmacologic therapy in survivors of sudden cardiac arrest".)

This topic will review the general indications for ICD implantation, the elements of the ICD, the features of ICD therapy and programming, and the role of adjunctive therapies in patients who receive an ICD. The clinical trials documenting the efficacy of an ICD in different clinical settings (including both secondary and primary prevention), complications of ICD placement, and follow-up care of patients with ICDs are discussed separately. (See "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy" and "Primary prevention of sudden cardiac death in heart failure and cardiomyopathy" and "Cardiac implantable electronic devices: Long-term complications" and "Cardiac implantable electronic devices: Patient follow-up" and "Cardiac implantable electronic devices: Peri-procedural complications".)


The main indications for use of an ICD relate to secondary prevention in patients with prior sustained ventricular tachycardia (VT), ventricular fibrillation (VF), or resuscitated sudden cardiac death (SCD) thought to be due to VT/VF as well as primary prevention in patients at increased risk of life-threatening VT/VF. The 2008 American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) guidelines for device-based therapy of cardiac rhythm abnormalities include guidelines for ICD therapy, and in 2013 numerous professional societies (including ACC, AHA, and HRS) jointly published appropriate use criteria discussing indications for ICD and cardiac resynchronization therapy [3,4].

Indications for ICD therapy

Secondary prevention — Implantation of an ICD is recommended for the secondary prevention of death due to VT/VF in the following settings [3]:

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Literature review current through: Sep 2017. | This topic last updated: Nov 16, 2016.
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