From the Guidelines
Amiodarone does not have a significant negative impact on cardiac function, and in some cases, it may even improve left ventricular ejection fraction (LVEF) and decrease the incidence of worsening heart failure, as noted in studies such as 1 and 1.
Key Points
- Amiodarone is a class III antiarrhythmic agent with a unique pharmacological profile that distinguishes it from other drugs in its class, as discussed in 1.
- It has been associated with overall neutral effects on survival in patients with low ejection fraction and heart failure, as reported in 1 and 1.
- Amiodarone may have beneficial effects on cardiac function, including increasing LVEF and reducing the incidence of worsening heart failure, as mentioned in 1.
- However, it is essential to weigh these potential benefits against the risks of adverse effects, such as thyroid abnormalities, pulmonary toxicity, hepatotoxicity, neuropathy, and other reactions, as highlighted in 1, 1, and 1.
Clinical Considerations
- The use of amiodarone should be individualized, taking into account the patient's specific clinical context and the potential risks and benefits, as emphasized in 1.
- Regular monitoring of thyroid, liver, and pulmonary function is necessary for patients on long-term amiodarone therapy, as recommended in 1.
- Amiodarone may be considered as an adjunct to other treatments, such as implantable cardioverter-defibrillators (ICDs), to reduce the frequency of shocks or control atrial fibrillation in selected patients, as discussed in 1.
From the FDA Drug Label
Amiodarone HCl injection has been reported to produce negative inotropic and vasodilatory effects in animals and humans In clinical studies of patients with refractory VF or hemodynamically unstable VT, treatment-emergent, drug related hypotension occurred in 288 of 1836 patients (16%) treated with amiodarone HCl injection.
Amiodarone can affect cardiac function by producing:
- Negative inotropic effects
- Vasodilatory effects
- Hypotension in some patients (16% in clinical studies) 2
From the Research
Effects of Amiodarone on Cardiac Function
- Amiodarone is a potent antiarrhythmic drug that has been successfully used in the treatment of symptomatic and life-threatening ventricular arrhythmias and symptomatic supraventricular arrhythmias 3.
- In patients with left ventricular dysfunction, amiodarone does not usually produce any clinically significant cardiodepression 3, 4.
- Amiodarone has a beneficial effect on mortality and survival in certain groups of patients with ventricular arrhythmias, an action probably related to both its antiarrhythmic and antifibrillatory effects 3.
- The drug can be safely used in patients with left ventricular dysfunction after myocardial infarction or those with congestive heart failure or hypertrophic cardiomyopathy 4.
Adverse Effects of Amiodarone on Cardiac Function
- Amiodarone's use is regularly accompanied with QT and QTc-interval prolongation but rarely with ventricular proarrhythmia 4.
- Cardiovascular side effects are uncommon, but symptomatic pulmonary side effects can occur in some patients 5.
- Amiodarone can cause thyroid dysfunction, including amiodarone-induced thyrotoxicosis (AIT) and amiodarone-induced hypothyroidism (AIH) 6, 7.
Monitoring and Treatment
- Patients treated with amiodarone require close supervision by the treating physician, including regular assessments and monitoring for signs of thyroid dysfunction 4, 6, 7.
- Treatment of amiodarone-induced thyroid dysfunction can include thionamides, glucocorticoids, and thyroid hormone replacement therapy 6, 7.
- The use of minimum effective doses and serial screening for thyroid, liver, and pulmonary toxicity are necessary to minimize the risk of adverse effects 4.