Do you avoid adenosine for atrial fibrillation (Afib) with aberrant conduction?

From the Guidelines

Adenosine should be avoided in atrial fibrillation (AFib) with aberrancy, as it may cause harm and is not recommended in this scenario. According to the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1, adenosine is potentially harmful in patients with WPW syndrome who have pre-excited AF. The guideline states that IV amiodarone, adenosine, digoxin, or nondihydropyridine calcium channel antagonists should be avoided in these patients, as they may cause a paradoxical increase in the ventricular response.

Instead, if a patient has AFib with aberrancy and requires rate control, consider the following options:

• Beta-blockers (such as metoprolol 5mg IV, repeated up to 15mg)
• Calcium channel blockers (diltiazem 0.25 mg/kg IV over 2 minutes) If the patient is hemodynamically unstable, synchronized cardioversion would be the appropriate management. The key to managing AFib with aberrancy is to recognize it correctly and distinguish it from ventricular tachycardia, which requires different management approaches.

The American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care also support avoiding AV nodal blocking agents such as adenosine, calcium channel blockers, digoxin, and possibly beta-blockers in patients with pre-excitation atrial fibrillation 1. This is because these drugs may cause a paradoxical increase in the ventricular response, leading to hemodynamic compromise.

In summary, adenosine is not recommended for AFib with aberrancy due to the potential for harm, and alternative rate control strategies should be considered.

From the FDA Drug Label

5.1 Cardiac Arrest, Ventricular Arrhythmias, and Myocardial Infarction Fatal and nonfatal cardiac arrest, sustained ventricular tachycardia (requiring resuscitation), and myocardial infarction have occurred following adenosine infusion Avoid use in patients with symptoms or signs of acute myocardial ischemia, for example, unstable angina or cardiovascular instability; these patients may be at greater risk of serious cardiovascular reactions to adenosine injection.

Avoiding Adenosine for Afib with Aberrancy:

• The FDA drug label warns against using adenosine in patients with symptoms or signs of acute myocardial ischemia or cardiovascular instability.
• Afib with aberrancy may be considered a form of cardiovascular instability, and therefore, adenosine should be avoided in these patients.
• The label does not explicitly address Afib with aberrancy, but the warnings regarding cardiovascular instability and acute myocardial ischemia suggest caution when using adenosine in such cases 2, 2, 2.

From the Research

Atrial Fibrillation with Aberrancy and Adenosine Use

• There is no direct evidence in the provided studies regarding the use of adenosine for atrial fibrillation (Afib) with aberrancy.
• However, the studies discuss the comparison of rate control efficacy between beta-blockers and calcium channel blockers in patients with Afib 3, 4, 5, 6, 7.
• Beta-blockers and calcium channel blockers are commonly used for rate control in Afib, and the selection between these two medications depends on various factors, including patient characteristics and comorbidities.
• Some studies suggest that beta-blockers may be more effective in reducing heart rate and shortening hospitalization duration in certain patient populations 3, 6.
• Calcium channel blockers, on the other hand, may be associated with less bradycardia during sinus rhythm compared to beta-blockers 6.
• The use of adenosine in Afib with aberrancy is not explicitly addressed in the provided studies, and therefore, no conclusions can be drawn based on the available evidence.