When is implantable cardioverter-defibrillator (ICD) placement indicated?

Updated: Oct 11, 2019
  • Author: Daniel M Beyerbach, MD, PhD; Chief Editor: Jeffrey N Rottman, MD  more...
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Indications for ICD implantation can be divided into two broad categories: secondary prophylaxis against sudden cardiac death and primary prophylaxis. For secondary prophylaxis, ICD placement is indicated as initial therapy in survivors of cardiac arrest due to ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT). Published guidelines exclude cases in which there are “transient or reversible causes,” [1] although in the specifics of its application this exclusion is somewhat controversial.

Currently, indications for primary prophylaxis account for most ICD implants. Measurable quantitative benefit is smaller in the primary prophylaxis population than in the secondary prophylaxis population. Class I indications (ie, the benefit greatly outweighs the risk, and the treatment should be administered) are as follows:

  • Structural heart disease, sustained VT

  • Syncope of undetermined origin, inducible VT or VF at electrophysiologic study (EPS)

  • Left ventricular ejection fraction (LVEF) ≤35% due to prior MI, at least 40 days post-MI, NYHA class II or III

  • LVEF ≤35%, NYHA class II or III

  • LVEF ≤30% due to prior MI, at least 40 days post-MI

  • LVEF ≤40% due to prior MI, inducible VT or VF at EPS

Class IIa indications (ie, the benefit outweighs the risk and it is reasonable to administer the treatment) are as follows:

  • Unexplained syncope, significant LV dysfunction, nonischemic cardiomyopathy

  • Sustained VT, normal or near-normal ventricular function

  • Hypertrophic cardiomyopathy with one or more major risk factors

  • Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) with one or more risk factors for sudden cardiac death (SCD)

  • Long QT syndrome, syncope or VT while receiving beta-blockers

  • Nonhospitalized patients awaiting heart transplant

  • Brugada syndrome, syncope or VT

  • Catecholaminergic polymorphic VT, syncope or VT while receiving beta-blockers

  • Cardiac sarcoidosis, giant cell myocarditis, or Chagas disease

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