Antiarrhythmic Medication Guidelines

Contraindications and Precautions

The American Heart Association recommends that digoxin is contraindicated in patients with AV block, particularly those with pre-existing conduction disease, and is also particularly dangerous in patients with pre-excitation syndromes (e.g., WPW) 1
The American Heart Association recommends that Class IC antiarrhythmics, such as flecainide and propafenone, are contraindicated in patients with sinus or AV conduction disease (in absence of pacemaker) 1, 2
The American Heart Association recommends that Class III antiarrhythmics, such as sotalol, are contraindicated in patients with sinus or AV nodal dysfunction (in absence of pacemaker) 1
The American Heart Association recommends that amiodarone and dofetilide be used with caution in patients with conduction disorders 1, 2

Beta-blockers, such as metoprolol, atenolol, propranolol, nadolol, and carvedilol, can cause AV block, particularly in patients with pre-existing conduction disease or elderly patients, with a strength of evidence level of IIa, according to the American Heart Association 1
Calcium channel blockers, such as verapamil and diltiazem, can cause AV block, especially in patients with pre-existing AV conduction disease or concomitant use with beta-blockers, with a strength of evidence level of IIa, according to the European Society of Cardiology 1
Digoxin can cause AV block, particularly in patients with renal dysfunction, electrolyte abnormalities, or concomitant use with other AV nodal blocking agents, with a strength of evidence level of IIb, according to the American Heart Association 1
Antiarrhythmic medications, such as flecainide, propafenone, disopyramide, and procainamide, can cause AV block, especially in patients with pre-existing conduction disease or structural heart disease, with a strength of evidence level of IIb, according to the European Heart Rhythm Association 1, 3

The combination of beta-blockers and non-dihydropyridine calcium channel blockers can cause profound bradycardia, heart block, and cardiovascular collapse, with a strength of evidence level of III, according to the American College of Cardiology 4
The combination of digoxin and beta-blockers or calcium channel blockers can have a synergistic effect on slowing AV conduction, requiring dose reduction, with a strength of evidence level of IIb, according to the American Heart Association 1
The use of multiple AV nodal blocking agents increases the risk of AV block, particularly with triple therapy, with a strength of evidence level of III, according to the American College of Cardiology 4

Baseline ECG and follow-up ECG after dose increases or addition of other AV nodal blocking agents are recommended to monitor for PR interval prolongation, with a strength of evidence level of I, according to the American Heart Association 1
Pharmacological stress testing with class IA antiarrhythmic agents can identify patients at high risk for developing AV block, with a strength of evidence level of IIb, according to the European Heart Rhythm Association 3
Elderly patients, patients with pre-existing conduction disease, renal or hepatic dysfunction, multiple AV nodal blocking agents, and electrolyte abnormalities are at high risk for developing AV block, with a strength of evidence level of IIa, according to the American Heart Association 1

The American Heart Association recommends that in patients with atrial fibrillation and AV block, medications that slow AV conduction should be avoided as they may mask the underlying rhythm disorder while worsening the conduction problem 2
Beta-blockers, calcium channel blockers, digoxin, and certain antiarrhythmic medications are the most common medications that cause AV block by slowing conduction through the AV node, according to the American Heart Association 1
The American College of Cardiology recommends considering the mechanism of action for each medication, including antagonizing sympathetic tone in nodal tissue, inhibiting calcium influx, increasing vagal tone, and sodium or potassium channel blockade, when assessing the risk of AV block 1