What is the role of Amiodarone in treating cardiomyopathy?

From the Guidelines

Amiodarone has no role in reducing mortality in patients with cardiomyopathy.

Key Points

• The SCD-HeFT trial, which enrolled 2521 patients with non-ischaemic dilated cardiomyopathy or ischaemic HF, showed that amiodarone did not reduce mortality 1.
• The study found that ICD treatment led to a 23% reduction in total mortality, but amiodarone did not provide any survival benefit 1.
• Other studies, such as the DEFINITE trial, have also shown that ICD therapy is superior to amiodarone in reducing mortality in patients with non-ischaemic cardiomyopathy 1.
• Amiodarone may be used for the management of life-threatening arrhythmias during acute heart failure, but its use is not recommended for primary prevention of sudden cardiac death in patients with cardiomyopathy 1.
• The guidelines recommend that ICD therapy should be considered for primary prevention of sudden cardiac death in patients with non-ischaemic cardiomyopathy and an EF ≤35% 1.
• Biventricular pacing may also be considered for the treatment of patients with non-ischaemic cardiomyopathy and a wide-QRS complex, as it has been shown to reduce mortality and hospital admissions for heart failure 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY Mechanisms of Action Amiodarone is generally considered a class III antiarrhythmic drug, but it possesses electrophysiologic characteristics of all four Vaughan Williams classes.

The role of Amiodarone in treating cardiomyopathy is not directly stated in the provided drug labels. However, Amiodarone is used to treat certain types of arrhythmias, which can be associated with cardiomyopathy.

• Amiodarone has electrophysiologic effects on the heart, including prolonging the cardiac action potential and slowing conduction.
• It is used to treat ventricular fibrillation and hemodynamically unstable ventricular tachycardia.
• The labels do not provide information on the use of Amiodarone for treating cardiomyopathy specifically 2, 2.

From the Research

Role of Amiodarone in Cardiomyopathy

• Amiodarone has been reported to reduce the likelihood of sudden death in patients with hypertrophic cardiomyopathy (HCM) 3.
• The drug may have contributed to the absence of sudden cardiac death in patients believed to be at higher risk because of multiple repetitive non-sustained ventricular tachycardia (NSVT) 3.
• Amiodarone improved symptoms and prevented sudden death in patients with symptomatic hypertrophic cardiomyopathy, but was associated with a significant risk of sudden death, particularly within the first 5 months of treatment 4.

Amiodarone in Congestive Heart Failure

• Amiodarone did not reduce overall mortality in patients with congestive heart failure and asymptomatic ventricular arrhythmias, but was effective in suppressing ventricular arrhythmias and improving ventricular function 5.
• There was a trend toward a reduction in overall mortality among patients with nonischemic cardiomyopathy who received amiodarone 5.
• Amiodarone possesses significant antiarrhythmic activity in heart failure patients and appears to be well tolerated, with proarrhythmia being uncommon 6.

Contemporary Management of Cardiac Arrhythmias

• Amiodarone is a potent coronary and peripheral vasodilator and can be safely used in patients with left ventricular dysfunction after myocardial infarction or those with congestive heart failure or hypertrophic cardiomyopathy 7.
• The drug reduces the rate of arrhythmic death due to ventricular tachyarrhythmias in patients with heart failure, but its benefit on cardiovascular and overall survival in these patients is uncertain 7.
• Amiodarone is an important adjuvant drug for the reduction of shocks in patients with an implantable cardioverter-defibrillator, but requires close supervision by the treating physician due to the risk of non-cardiac toxicity and common drug-drug interactions 7.