Indications for an ICD

# Class I
1. Cardiac arrest due to ventricular fibrillation (VF) or ventricular tachycardia (VT) not due to a transient or reversible cause. (Level of evidence: A)
2. Spontaneous sustained VT in association with structural heart disease. (Level of evidence: B)
3. Syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiologic study when drug therapy is ineffective, not tolerated, or not preferred. (Level of evidence: B)
4. Nonsustained VT in patients with coronary artery disease, prior myocardial infarction (MI), left ventricular (LV) dysfunction, and inducible VF or sustained VT at electrophysiologic study that is not suppressible by a Class I antiarrhythmic agent. (Level of evidence: A)
5. Spontaneous sustained VT in patients who do not have structural heart disease that is not amenable to other treatments. (Level of evidence: C)

# Class IIa
1. Patients with LV ejection fraction of 30% or less, at least 1 month post-MI and 3 months post coronary artery revascularization surgery. (Level of evidence: B)

# Class IIb
1. Cardiac arrest presumed to be due to VF when electrophysiologic testing is precluded by other medical conditions. (Level of evidence: C)
2. Severe symptoms (eg, syncope) attributable to sustained ventricular tachyarrhythmias in patients awaiting cardiac transplantation. (Level of evidence: C)
3. Familial or inherited conditions with a high risk for life threatening ventricular tachyarrhythmias, such as long QT syndrome or hypertrophic cardiomyopathy. (Level of evidence: B)
4. Nonsustained VT with coronary artery disease, prior MI, LV dysfunction, and inducible sustained VT or VF at electrophysiologic study. (Level of evidence: B)
5. Recurrent syncope of undetermined etiology in the presence of ventricular dysfunction and inducible ventricular arrhythmias at electrophysiologic study when other causes of syncope have been excluded. (Level of evidence: C)
6. Syncope of unexplained etiology or family history of unexplained sudden cardiac death in association with typical or atypical right bundle-branch block and ST-segment elevations (Brugada syndrome). (Level of evidence: C)
7. Syncope in patients with advanced structural heart disease in which thorough invasive and noninvasive investigation has failed to define a cause. (Level of evidence: C)

# Class III
1. Syncope of undetermined cause in a patient without inducible ventricular tachyarrhythmias and without structural heart disease. (Level of evidence: C)
2. Incessant VT or VF. (Level of evidence: C)
3. VT or VF resulting from arrhythmias amenable to surgical or catheter ablation; for example, atrial arrhythmias associated with the Wolff-Parkinson-White syndrome, right ventricular outflow tract VT, idiopathic LV tachycardia, or fascicular VT. (Level of evidence: C)
4. Ventricular tachyarrhythmias due to a transient or reversible disorder (eg, acute MI, electrolyte imbalance, drugs, or trauma) when correction of the disorder is considered feasible and likely to substantially reduce the risk of recurrent arrhythmia. (Level of evidence: B)
5. Significant psychiatric illnesses that may be aggravated by device implantation or may preclude systematic follow-up. (Level of evidence: C)
6. Terminal illnesses with projected life expectancy of 6 months or less. (Level of evidence: C)
7. Patients with coronary artery disease, LV dysfunction, and prolonged QRS duration in the absence of spontaneous or inducible sustained or nonsustained VT who are undergoing coronary bypass surgery. (Level of evidence: B)
8. NYHA Class 4 drug-refractory congestive heart failure in patients who are not candidates for cardiac transplantation. (Level of evidence: C)