Will ventricular tachycardia (VT) recur?

From the Guidelines

Ventricular tachycardia (VT) is likely to recur in patients with left ventricular dysfunction and sustained VT, and therefore, urgent catheter ablation in specialized or experienced centers is recommended to prevent recurrences and improve quality of life. The European Society of Cardiology (ESC) guidelines suggest that catheter ablation can decrease the rate of recurrent electrical storm episodes and improve outcomes in patients with VT related to post-myocardial scar 1.

Prevention of VT Recurrences

The guidelines recommend the following for prevention of VT recurrences:

• Urgent catheter ablation in specialized or experienced centers for patients presenting with incessant VT or electrical storm resulting in ICD shocks 1
• Amiodarone or catheter ablation for patients with recurrent ICD shocks due to sustained VT 1
• ICD implantation in patients undergoing catheter ablation whenever they satisfy eligibility criteria for ICD 1

Treatment Options

Treatment options for VT include:

• Antiarrhythmic medications like amiodarone, lidocaine, or procainamide for stable patients
• Implantable cardioverter-defibrillators (ICDs) for those at high risk of recurrence
• Catheter ablation for patients with scar-related heart disease presenting with VT or VF 1
• Beta-blocker therapy in combination with amiodarone to reduce the number of ICD shocks 1

Importance of ICD Implantation

ICD implantation is crucial in patients with sustained VT, as it increases survival compared with anti-arrhythmic drug therapy 1. The guidelines recommend considering ICD implantation in all patients with LV dysfunction (ejection fraction <45%) and sustained VT 1.

Quality of Life and Mortality

The primary goal of treatment is to improve quality of life and reduce mortality. Catheter ablation and ICD implantation can significantly improve outcomes in patients with VT, and therefore, these treatment options should be considered in all patients with sustained VT and left ventricular dysfunction.

From the FDA Drug Label

The acute effectiveness of amiodarone HCl injection in suppressing recurrent VF or hemodynamically unstable VT is supported by two randomized, parallel, dose-response studies of approximately 300 patients each In these studies, patients with at least two episodes of VF or hemodynamically unstable VT in the preceding 24 hours were randomly assigned to receive doses of approximately 125 or 1000 mg over the first 24 hours, an 8-fold difference. The prospectively defined primary efficacy end point was the rate of VT/VF episodes per hour. For both studies, the median rate was 0.02 episodes per hour in patients receiving the high dose and 0.07 episodes per hour in patients receiving the low dose, or approximately 0.5 versus 1.7 episodes per day (p=0. 07,2-sided, in both studies).

The FDA drug label does not provide a direct answer to whether ventricular tachycardia (VT) will recur. However, based on the available information, it can be inferred that:

• Amiodarone HCl injection is effective in suppressing recurrent VT or VF in patients refractory to other therapy.
• The rate of VT/VF episodes is reduced with amiodarone treatment, with a median rate of 0.02 episodes per hour in patients receiving the high dose and 0.07 episodes per hour in patients receiving the low dose.
• The time to first episode of VT/VF is prolonged with amiodarone treatment, with a significant difference in one study.
• However, mortality was not affected in these studies, and the long-term effectiveness of amiodarone in preventing VT recurrence is not established 2.

From the Research

Recurrence of Ventricular Tachycardia (VT)

The recurrence of VT is a significant concern in patients with implantable cardioverter-defibrillators (ICDs) as it can lead to increased morbidity and mortality 3, 4. Several studies have investigated the effectiveness of antiarrhythmic drugs and catheter ablation in preventing VT recurrence.

Treatment Options

• Antiarrhythmic drugs: These medications can be effective in suppressing VT, but they are limited by incomplete efficacy and unfavorable side effect profiles 3, 4.
• Catheter ablation: This procedure can be effective in reducing VT recurrence, particularly in patients with ischemic cardiomyopathy and an ICD who have VT despite antiarrhythmic drug therapy 3, 5, 6.

Outcomes

• The VANISH trial found that catheter ablation resulted in a 28% relative risk reduction in the composite endpoint of death, VT storm, and appropriate ICD shock compared to escalated antiarrhythmic drug therapy 3, 5.
• A study published in the New England Journal of Medicine found that catheter ablation was associated with a significantly lower rate of the composite primary outcome of death, VT storm, or appropriate ICD shock compared to escalated antiarrhythmic drug therapy 5.
• The relationship between VT burden and mortality is still unclear, with some studies suggesting an association but insufficient evidence to prove causality 7.

Factors Influencing Recurrence

• The presence of an ICD can mitigate the proarrhythmic mortality risk of antiarrhythmic drugs, but does not prevent recurrent VT episodes 4.
• The underlying substrate of the heart, such as ischemic cardiomyopathy, can influence the effectiveness of catheter ablation 6.
• The cumulative number of recurrent VTs or ICD shocks, defined as VT burden, may be associated with an elevated risk of death, but the causal relationship is still unclear 7.