Implantable Cardioverter Defibrillators (ICD)

CLASS I INDICATIONS evidence and/or general agreement that ICD’s are useful and effective

1. Survivors of cardiac arrest due to ventricular fibrillation or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any completely reversible causes

2. Structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable

3. Syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or ventricular fibrillation induced at electrophysiological study

4. LVEF less than or equal to 35 % due to prior myocardial infarction who are at least 40 days post–myocardial infarction and are in NYHA functional Class II or III

5. Nonischemic dilated Cardiomyopathy who have an LVEF less than or equal to 35 % and who are in NYHA functional Class II or III

6. LV dysfunction due to prior myocardial infarction who are at least 40 days post–myocardial infarction, have an LVEF less than or equal to 30 %, and are in NYHA functional Class I

7. Nonsustained VT due to prior myocardial infarction, LVEF less than or equal to 40 %, and inducible ventricular fibrillation or sustained VT at electrophysiological study

CLASS IIa INDICATIONS conflicting evidence about the usefulness of ICD therapy, with the weight of evidence/opinion in favor of usefulness/efficacy

1. Reasonable for patients with unexplained syncope, significant LV dysfunction, and nonischemic cardiomyopathy

2. Reasonable for patients with sustained VT and normal or near-normal ventricular function

3. Reasonable for patients with hypertrophic cardiomyopathy who have 1 or more major risk factor for SCD

4. Reasonable for the prevention of SCD in patients with arrythmogenic RV dysplasia who have 1 or more risk factors for SCD

5. Reasonable to reduce SCD in patients with long-QT syndrome who are experiencing syncope and/or VT while receiving beta blockers

6. Reasonable for non hospitalized patients awaiting for transplantation

7. Reasonable for patients with Brugada syndrome with syncope or who have documented VT that has not resulted in cardiac arrest

8. Reasonable for patients with catecholaminergic polymorphic VT who have syncope and/or documented sustained VT while receiving beta blockers

9. Reasonable for patients cardiac sarcoidosis, giant cell myocarditis, or Chagas disease

CLASS IIb INDICATIONS usefulness/efficacy is less well established by evidence/opinion

1. Considered in patients with nonischemic heart disease who have an LVEF of less than or equal to 35 % and who are in NYHA functional class I

2. Considered for patients with long-QT syndrome and risk factors for SCD

3. Considered in patients with syncope and advanced structural heart disease in whom through invasive and noninvasive investigations have failed to define a cause

4. Considered in patients with a familial cardiomyopathy associated with SCD

5. Considered in patients with LV noncompaction

From Ref. [1]

Contraindications

Major ICD implantation contraindications are included in the ACC/AHA/HRS guidelines (See Table 25.2). Other contraindications are: Hemodynamically unstable patients, in the setting of acute myocardial ischemia or hypoxia, post coronary artery bypass surgery, in the setting of active infection in the chest wall or bloodstream infections, with electrolyte imbalances and with drug toxicities [2, 3].

Table 25.2

CLASS III conditions for which there is a general agreement that ICD’s are not useful and possibly harmful

1. Not indicated for patients who do not have a reasonable expectation of survival with an acceptable functional status for at least 1 year, even if they meet ICD implantation criteria

2. Not indicated for patients with incessant VT or VF

3. Not indicated in patients with significant psychiatric illnesses that may be aggravated by device implantation or that may preclude systematic follow-up

4. Not indicated for NYHA class IV patients with drug-refractory congestive heart failure who are not candidates for cardiac transplantation or CRT-D

5. Not indicated for syncope of undetermined cause in a patient without inducible ventricular tachyarrhythmias and without structural heart disease

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