Modification of digoxin induced arrhythmogenicity in adult rats following atropine administration

Atropine alone in the two lower doses (20 mg/kg and 40 mg/kg) did not produce any arrhythmias while 80 mg/kg of atropine produced arrhythmias in 33% of animals after 31.0 ± 7.5 min. Only 11% of these rats developed paroxysmal atrial tachycardia. Atropine in lower doses (20, 40 mg/kg) with digoxin (40 mg/kg) decreased the total percent of digoxin induced arrhythmias, delayed their onset, and changed the type of arrhythmias as compared with the digoxin group alone. Atropine given in higher dosage (80 mg/kg) with digoxin (40 mg/kg) produced arrhythmias in 100% of rats as did digoxin alone, but significantly shortened their onset and modified the types of arrhythmias seen. In conclusion, atropine in varying doses significantly modified digoxin toxicity.