What arrhythmia is commonly associated with digitalis (digoxin) toxicity?

From the Guidelines

Atrial fibrillation with slow ventricular response, as well as enhanced atrial, junctional, or ventricular automaticity often combined with atrioventricular block, are common arrhythmias associated with digitalis toxicity. Digitalis (digoxin) can cause various cardiac arrhythmias when blood levels become toxic, and these arrhythmias can be life-threatening if not recognized and treated promptly 1. The dual effects of digitalis on the heart, including increased vagal tone and enhanced automaticity, contribute to the development of these arrhythmias. Other arrhythmias that may occur with digitalis toxicity include:

• Premature ventricular contractions (PVCs)
• Paroxysmal atrial tachycardia with block
• Bidirectional ventricular tachycardia
• Various degrees of AV block

Patients with suspected digitalis toxicity should have their serum digoxin levels checked immediately, and the drug should be withheld 1. Treatment may include administration of digoxin-specific antibody fragments (Digibind) in severe cases, as well as intravenous magnesium and temporary pacing 1. Electrolyte abnormalities, particularly hypokalemia, can potentiate digitalis toxicity, so potassium levels should be monitored and corrected as needed. According to the most recent guidelines, discontinuing the drug, monitoring rhythm, and maintaining normal serum potassium are essential steps in managing digitalis toxicity 1.

From the Research

Digitalis Toxicity and Arrhythmias

• Digitalis toxicity can cause a variety of cardiac arrhythmias, including multifocal or unifocal multiform ventricular ectopic beats, bidirectional tachycardia, complete heart block, accelerated junctional rhythm with exit block, nonparoxysmal junctional tachycardia, atrial fibrillation, atrial tachycardia with block, and multifocal tachycardia 2
• The presence of multiple arrhythmias occurring simultaneously should suggest the high possibility of digitalis intoxication 2
• Bidirectional VT or accelerated idioventricular rhythm are characteristic of digitalis toxicity 3
• Digitalis can cause a variety of supraventricular arrhythmias; atrial tachycardia with block and nonparoxysmal atrioventricular junctional tachycardia are the most characteristic 3
• Other arrhythmias associated with digitalis toxicity include sinus bradycardia, atrioventricular block, nonparoxysmal atrioventricular junctional tachycardia, and ventricular tachycardia 4

Common Arrhythmias in Digitalis Toxicity

• Bidirectional tachycardia 2, 3
• Atrial tachycardia with block 2, 3
• Nonparoxysmal atrioventricular junctional tachycardia 2, 3, 4
• Ventricular tachycardia 2, 3, 4