What are the guidelines for primary prevention of Implantable Cardioverter-Defibrillator (ICD)?

From the Guidelines

Primary prevention implantable cardioverter-defibrillators (ICDs) are recommended for patients with nonischemic DCM or ischemic heart disease at least 40 days post-MI with LVEF ≤35% and NYHA class II or III symptoms on chronic GDMT, who have reasonable expectation of meaningful survival for >1 year, to reduce total mortality. The guidelines for primary prevention ICD implantation are based on the patient's left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) class, and the presence of ischemic or nonischemic cardiomyopathy.

Key Indications for Primary Prevention ICD

• Nonischemic DCM or ischemic heart disease at least 40 days post-MI with LVEF ≤35% and NYHA class II or III symptoms on chronic GDMT 1
• Patients at least 40 days post-MI with LVEF ≤30% and NYHA class I symptoms while receiving GDMT, who have reasonable expectation of meaningful survival for >1 year 1

Considerations for ICD Implantation

• Patients should have a reasonable expectation of meaningful survival for more than 1 year 1
• Patients should be on chronic GDMT and have a LVEF ≤35% for nonischemic DCM or ischemic heart disease 1
• A transvenous ICD provides high economic value in the primary prevention of SCD particularly when the patient’s risk of death caused by ventricular arrhythmia is deemed high and the risk of nonarrhythmic death is deemed low based on the patient’s burden of comorbidities and functional status 1

Additional Considerations

• Before ICD implantation, patients should receive optimal heart failure medications including beta-blockers, ACE inhibitors/ARBs/ARNI, mineralocorticoid receptor antagonists, and SGLT2 inhibitors as appropriate
• ICDs work by detecting and terminating life-threatening ventricular arrhythmias, thereby preventing sudden cardiac death in vulnerable populations. The most recent and highest quality study supporting these guidelines is the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1.

From the Research

Guidelines for Primary Prevention ICD

The guidelines for primary prevention implantable cardioverter-defibrillators (ICDs) are based on several factors, including:

• Left ventricular ejection fraction (LVEF) of 35% or less after at least 3 months of optimized heart failure treatment 2
• Presence of heart failure with reduced ejection fraction (HFrEF) 2, 3
• Symptomatic HFrEF caused by coronary artery disease or non-ischaemic aetiology 2

Patient Selection

Patient selection for primary prevention ICD is crucial, and several factors should be considered, including:

• Age: Advanced age is independently associated with complications at the time of device placement, but not the risk of device infection 4
• Life expectancy: ICDs are cost-effective from societal and health care sector perspectives, provided life expectancy exceeds 1 year 4
• Comorbidities: Presence of comorbidities, such as diabetes, hypertension, and chronic kidney disease, should be considered when selecting patients for primary prevention ICD 4
• Quality of life: ICDs generally do not adversely impact quality of life, but a subset of patients may experience post-traumatic stress disorder 4

Medical Therapies

Medical therapies, such as:

• Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers
• Beta-blockers (BB)
• Mineralocorticoid receptor antagonists (MRA)
• Neprilysin inhibition
• Sodium-glucose cotransporter 2 inhibitors (SGLT2i) can reduce the risk of sudden cardiac death in patients with HFrEF and may impact the need for primary prevention ICD 2, 3

Device Selection and Programming

Device selection and programming should be individualized, taking into account the patient's specific needs and characteristics, including:

• Type of device: Subcutaneous ICDs, multi-chamber devices, and cardiac resynchronization therapy devices 5, 6
• Programming: Physiologic bradycardic pacing, atrial and ventricular therapeutic pacing algorithms, and shock therapy 5