Digoxin can cause many different ECG abnormalities when supratherapeutic levels occur.
The classic digoxin effect appears as a downsloping ST segment depression, also known as the "reverse tick" or "reverse check" sign.
Digoxin toxicity can induce literally every arrhythmia except for rapidly conducted atrial arrhythmias (atrial fibrillation and atrial flutter). The classic arrhythmias seen during digoxin toxicity include atrial tachycardia with a 2:1 conduction, bidirectional ventricular tachycardia and atrial fibrillation with a slow ventricular response.
1. Surawicz B, et al. Circulation. 2009;119:e235-240.
2. Chou's Electrocardiography in Clinical Practice: Adult and Pediatric, Sixth Edition, Saunders, Philadelphia, 2008.