Is implantable cardioverter-defibrillator (ICD) placement justified in patients with runs of ventricular tachycardia (VT)?

From the Guidelines

ICD placement is justified in patients with runs of ventricular tachycardia (VT), particularly those with sustained VT episodes, structural heart disease, and reduced left ventricular ejection fraction (LVEF ≤35%). The decision to place an ICD in patients with VT should be individualized based on several key factors, including the presence of sustained VT, structural heart disease, prior myocardial infarction, or other significant cardiac abnormalities 1. For patients with non-sustained VT, the decision requires careful risk stratification, and medical therapy should be optimized first, including beta-blockers and antiarrhythmic medications like amiodarone when appropriate.

The underlying cause of VT should be identified and treated when possible, including coronary revascularization for ischemic disease, heart failure management, or correction of electrolyte abnormalities. Electrophysiology studies may help determine risk in uncertain cases. According to the 2015 ESC guidelines, ICD implantation should be considered in all patients with LV dysfunction (ejection fraction <45%) and sustained VT 1. Additionally, studies have shown that ICDs can reduce mortality in patients with heart failure and reduced LVEF, with a relative mortality decrease of 23% over a 5-year period 1.

However, it is also important to consider the potential risks and limitations of ICD placement, including the risk of inappropriate shocks, device malfunction, and the potential for ICDs to aggravate heart failure. Therefore, careful attention to the details of ICD implantation, programming, and pacing function is important for all patients with low EF who are treated with an ICD 1. The justification for ICD placement ultimately depends on the patient's overall risk of sudden cardiac death, with stronger justification in those with sustained VT, structural heart disease, or other high-risk features.

Key considerations for ICD placement in patients with VT include:

• Presence of sustained VT episodes
• Structural heart disease
• Reduced left ventricular ejection fraction (LVEF ≤35%)
• Prior myocardial infarction
• Other significant cardiac abnormalities
• Optimization of medical therapy, including beta-blockers and antiarrhythmic medications
• Identification and treatment of underlying cause of VT
• Electrophysiology studies to determine risk in uncertain cases.

From the Research

Indications of ICD in Runs of VT

The placement of an implantable cardioverter-defibrillator (ICD) in patients with runs of ventricular tachycardia (VT) is a significant consideration in the management of life-threatening arrhythmias. Several studies have investigated the efficacy and safety of ICD placement in this context.

Efficacy of ICD Placement

• A study published in 2000 2 found that patients with unexplained syncope, structural heart disease, and inducible ventricular tachycardia at electrophysiologic study had a high rate of ICD discharge, suggesting that ICD placement is justified in this population.
• A more recent study published in 2022 3 compared the efficacy and safety of catheter ablation versus antiarrhythmic drug therapy as first-line treatment in ICD patients with symptomatic ventricular tachycardias, and found that catheter ablation reduced the composite endpoint of cardiovascular death, appropriate ICD shock, hospitalization due to heart failure, or severe treatment-related complications.
• Another study published in 2019 4 found that amiodarone and catheter ablation were associated with significantly reduced ICD shocks, while sotalol was associated with increased ICD shocks compared to amiodarone.

Safety and Considerations

• The study published in 2017 5 highlighted the importance of a shared clinical decision process, taking into account patients' cardiac status, comorbidities, and goals of care, when considering ICD placement and management of VT.
• The study published in 2007 6 discussed the role of defibrillation testing in ICD placement, and suggested that while advances in technology have improved the safety and efficacy of ICD placement, defibrillation testing may still be necessary in certain cases.

Key Findings

• ICD placement is justified in patients with runs of VT, particularly those with structural heart disease and inducible ventricular tachycardia at electrophysiologic study 2.
• Catheter ablation and antiarrhythmic drug therapy, such as amiodarone, are effective in reducing ICD shocks and improving outcomes in patients with VT 3, 4.
• A shared clinical decision process is essential in the management of VT and ICD placement, taking into account individual patient characteristics and goals of care 5.