Why is adenosine not used for atrial fibrillation (AFib)?

From the Guidelines

Adenosine is not recommended for treating atrial fibrillation due to its ineffective mechanism of action in this specific arrhythmia. Adenosine works by temporarily blocking the AV node, which slows conduction between the atria and ventricles, making it useful for terminating AV nodal reentrant tachycardias and other supraventricular tachycardias that depend on the AV node as part of their circuit, as stated in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. However, in atrial fibrillation, there are multiple chaotic electrical circuits in the atria that operate independently of the AV node. Adenosine may briefly slow ventricular response by blocking the AV node, but this effect is extremely short-lived (seconds) and doesn't convert the atrial fibrillation back to normal sinus rhythm.

Some key points to consider in the management of atrial fibrillation include:

• The use of rate control medications such as beta-blockers or calcium channel blockers to control ventricular rate.
• The use of rhythm control medications such as amiodarone or flecainide to maintain sinus rhythm, as recommended in the 2024 ESC guidelines for the management of atrial fibrillation 1.
• The consideration of electrical cardioversion or catheter ablation in selected patients.
• The importance of anticoagulation to prevent stroke in patients with atrial fibrillation, especially those with high risk factors.

It's also important to note that the 2024 ESC guidelines recommend specific antiarrhythmic drugs for long-term maintenance of sinus rhythm, including amiodarone, dronedarone, flecainide, and propafenone, with careful consideration of the patient's underlying conditions and potential side effects 1. In summary, adenosine is not a suitable treatment option for atrial fibrillation, and other treatments such as rate control, rhythm control, electrical cardioversion, or anticoagulation should be considered instead.

From the FDA Drug Label

5.8 Atrial Fibrillation Adenosine injection can cause atrial fibrillation in patients with or without a history of atrial fibrillation. You can't use adenosine for atrial fibrillation because adenosine injection can cause atrial fibrillation in patients with or without a history of atrial fibrillation 2.

• Key points:
  • Adenosine can induce atrial fibrillation
  • Atrial fibrillation can occur in patients with or without a history of atrial fibrillation
  • Atrial fibrillation typically began 1.5 to 3 minutes after initiation of adenosine injection, lasted for 15 seconds to 6 hours, and spontaneously converted to normal sinus rhythm 2

From the Research

Adenosine and Atrial Fibrillation

• Adenosine is not typically used to treat atrial fibrillation due to its potential to precipitate atrial arrhythmias 3.
• A study found that adenosine led to atrial fibrillation in 12% of patients with paroxysmal supraventricular tachycardia (PSVT) 3.
• The mechanism of adenosine-induced atrial fibrillation is thought to be related to a "long-short" atrial sequence, where an atrial premature complex occurs after a short interval, leading to atrial fibrillation 3.
• Adenosine may be misused for atrial fibrillation due to errors in rhythm diagnosis, with 31% of house officers misdiagnosing a 12-lead electrocardiogram of rapid atrial fibrillation as paroxysmal supraventricular tachycardia 4.
• Alternative treatments for atrial fibrillation, such as beta-blockers and calcium channel blockers, are available and may be more effective in controlling ventricular rate 5, 6.

Alternative Treatments for Atrial Fibrillation

• Beta-blockers and calcium channel blockers are commonly used to control ventricular rate in atrial fibrillation 5, 6.
• Beta-blockers are preferred in patients with myocardial ischemia, myocardial infarction, and hyperthyroidism, while non-dihydropyridine calcium channel blockers are preferred in patients with bronchial asthma and chronic obstructive pulmonary disease 6.
• The choice of treatment depends on the individual patient's clinical situation and underlying conditions 6.

Adenosine Receptors and Atrial Fibrillation

• The adenosinergic system, including adenosine receptors, plays a role in the pathophysiology of atrial fibrillation 7.
• Activation of adenosine receptors, such as A1, A2A, A2B, and A3, can modulate atrial fibrillation by promoting delayed depolarization, shortening action potential duration, and inducing resting membrane potential hyperpolarization 7.
• The adenosinergic system may also modulate the autonomous nervous system and is associated with atrial fibrillation risk factors 7.