[Adverse effects of antiarrhythmic drugs in patients with atrial fibrillation in primary care]

Abstract

Background and objective: To determine the adverse effects (AE) of antiarrhythmic drugs used to treat atrial fibrillation (AF) in routine clinical practice.

Patients and methods: A retrospective, observational, population-based study of all patients diagnosed of AF requiring long-term treatment with antiarrhythmic drugs. We performed also a descriptive analysis of the type of EA, and their management (diagnostic techniques, laboratory tests, drug treatment, number of visits to health services, emergency visits, hospitalizations and surgeries).

Results: We included 400 patients. Overall, 688 treatments were started, 34 of which (4.9%) were implied in 32 EA in 30 patients. The most frequent EA were hypothyroidism (28.1%), hyperthyroidism (25%) and bradycardia (9.38%). In absolute numbers, class III drugs (Vaughan-Williams classification) were associated with a higher number of AE (p=0.001). The number of AE/100 patients-year was: class I 0.42 (0.01-1.15%), class II 2.55 (0.68-5.13%), class III 4.70 (2.98-6.64%), class IV 1.18 (0.14-2.80%), digoxin 0.41 (0.08-1.19). Individually, the drugs with a higher rate were sotalol, bisoprolol and amiodarone (5.70, 5.37 and 4.59 respectively). 93.75% of EA required visits to health services, 59.38% laboratory tests and 56.25% diagnostic techniques. The most frequent visits were scheduled for primary care (75%), followed by scheduled visits to outpatient cardiology (21.9%). 71.9% of EA were resolved without any sequel and one patient died.

Conclusions: Antiarrhythmic drugs for the management of AF are associated with the presence of AE, mainly class III drugs. In most cases they are not serious, but imply important health resources.