Does Amiodarone (antiarrhythmic medication) reduce sudden cardiac death in patients with Ventricular Tachycardia (VT)?

From the Guidelines

Amiodarone does not reduce sudden death in patients with ventricular tachycardia (VT) as evidenced by the lack of survival benefit in the SCD-HeFT trial 1. The use of amiodarone in patients with VT is generally reserved for those who are not candidates for implantable cardioverter-defibrillator (ICD) therapy or as a bridge to ICD implantation. According to the 2015 ESC guidelines, amiodarone may be considered in patients with VT when an ICD is not available, contraindicated, or refused by the patient 1. However, the guidelines also emphasize the importance of ICD therapy in reducing sudden cardiac death in patients with VT. The typical oral loading dose of amiodarone is 400-600 mg daily for 2-4 weeks, followed by a maintenance dose of 200-400 mg daily. For acute VT, intravenous amiodarone is given as a 150 mg bolus over 10 minutes, followed by 1 mg/min infusion for 6 hours, then 0.5 mg/min for 18 hours. Patients require regular monitoring for potential side effects, including thyroid dysfunction, pulmonary toxicity, liver abnormalities, and corneal deposits. ECG monitoring is essential as amiodarone can prolong the QT interval. The drug has a very long half-life (up to 100 days), so effects and side effects may persist for weeks to months after discontinuation. In terms of quality of life, ICDs have been shown to improve survival but may not necessarily improve functional capacity or delay heart failure progression 1. Therefore, the decision to use amiodarone or ICD therapy should be individualized based on the patient's specific clinical circumstances and preferences. Some key points to consider when deciding on therapy include:

• The patient's underlying heart disease and left ventricular function
• The presence of any comorbidities that may affect survival or quality of life
• The patient's preferences and values regarding treatment options
• The potential risks and benefits of amiodarone versus ICD therapy.

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 Mortality was not affected in these studies; at the end of double-blind therapy or after 48 hours, all patients were given open access to whatever treatment (including amiodarone HCl injection) was deemed necessary.

Amiodarone reduces the rate of VT/VF episodes in patients with VT, but the available data from the provided drug label does not directly support the claim that it reduces sudden death in these patients 2.

From the Research

Amiodarone and Sudden Death in Patients with VT

• Amiodarone has been shown to reduce sudden cardiac death (SCD) in patients with ventricular tachycardia (VT) in certain contexts 3, 4.
• A study published in 2015 found that amiodarone reduced SCD, cardiac mortality, and all-cause mortality when compared to placebo or no intervention for primary prevention 3.
• However, the same study found that the quality of evidence for secondary prevention was very low, and amiodarone appeared to increase the risk of SCD and all-cause mortality when compared to placebo or no intervention 3.
• Another study published in 2020 noted that amiodarone reduces the rate of arrhythmic death due to ventricular tachyarrhythmias in patients with heart failure, but its benefit on cardiovascular and overall survival is uncertain 5.

Clinical Variables and Risk Stratification

• A 1985 study identified clinical variables such as an ejection fraction of less than 0.40, syncope or cardiac arrest before amiodarone therapy, and VT during predischarge ambulatory electrocardiographic monitoring as predictive of subsequent fatal or nonfatal cardiac arrest 6.
• Risk stratification using these clinical variables can predict which patients are at high risk of recurrent cardiac arrest or sudden death during amiodarone therapy 6.

Efficacy and Safety of Amiodarone

• Amiodarone has emerged as the leading antiarrhythmic therapy for termination and prevention of ventricular arrhythmia in different clinical settings due to its proven efficacy and safety 4.
• However, its use requires careful patient surveillance with respect to potential adverse effects, and long-term treatment should be based on the use of minimal doses for satisfactory arrhythmia outcome and serial screening for thyroid, liver, and pulmonary toxicity 5, 4.