Contemporary utilization of digoxin in patients with atrial fibrillation. Clinical Quality Improvement Network Investigators

OBJECTIVE: To define the contemporary practice patterns of digoxin utilization for the management of patients with atrial fibrillation (AF). METHODS: A retrospective medical records audit of 2490 patients with documented AF, from 12 Canadian hospitals and six outpatient clinics, during fiscal year 1993-1994, was conducted. RESULTS: There were 1158 women and 1332 men, with a mean age of 72 years; 956 patients were < 70 years of age and 1534 were > or = 70 years old. The majority of patients had nonvalvular AF (75% of those with a documented etiology). Paroxysmal AF (PAF) was documented in 800 patients, 936 had chronic AF, and 754 had new-onset AF. While the prescribing patterns were heterogeneous, the predominant strategy pursued in all subgroups appeared to be that of achieving rate control. Digoxin was the most commonly prescribed medication (79%) and was prescribed for the majority of patients in all subgroups, including patients with PAF (74%) and patients with a history of chronic AF who were currently in sinus rhythm (83%). Only 10% of the patients with PAF who were prescribed digoxin had congestive heart failure. Similarly, less than 25% of the patients with chronic AF who were prescribed digoxin after conversion to sinus rhythm had evidence of heart failure. CONCLUSIONS: In the absence of clinical trial evidence supporting either a strategy of antiarrhythmic therapy or rate control with anticoagulation, the appropriateness of the observed prescribing practices cannot be judged. However, digoxin is not the best rate-controlling agent for all patients and may be overused in certain subgroups of patients, such as those with PAF and those successfully converted to sinus rhythm.