Digitalis-induced cardiac arrhythmias: a report of 180 cases.

Abstract

Digitalis is an essential drug in the treatment of congestive heart failure and various supraventricular arrhythmias. However, digitalis may produce or aggravate congestive heart failure and almost every known cardiac arrhythmia. A recognition of digitalis-induced arrhythmias is extremely important because cardiac arrhythmias may often indicate digitalis intoxication without any other signs.One hundred and eighty patients with digitalis intoxication studied by this author were presented. The total incidence of digitalis-induced arrhythmias was 346 episodes. The overall incidence of ventricular arrhythmias was highest (104 patients) and, among these, ventricular premature contractions predominated. The basic rhythm was atrial fibrillation in 87 patients and almost all of these patients showed either nonparoxysmal A-V nodal tachycardia or A-V nodal escape rhythm. This information is extremely important since A-V nodal arrhythmia in the presence of atrial fibrillation are frequently misinterpreted as uncomplicated atrial fibrillation. Frequent occurrence of A-V dissociation with A-V nodal arrhythmias was emphasized. Nineteen patients had atrial tachycardia and A-V conduction disturbances were encountered in 64 patients.Sudden appearance of rapid or slow heart action during digitalization should make one suspect digitalis toxicity rather than need for increased digitalis. Immediate recognition of digitalis toxicity particularly digitalisinduced arrhythmias and withdrawal of digitalis are essential to minimize the relatively high mortality.