New use of antiarrhythmia drugs in Saskatchewan.

BACKGROUND

Cardiac dysrhythmias are a diverse group of disorders and many are associated with significant morbidity and mortality. Because their recent therapeutic management has not been adequately described, this study details the antiarrhythmia drugs that were dispensed to patients who had not received therapy in the preceding two years, and it evaluates the potential indications for the drugs as well as whether the therapy is consistent with the recommended procedures.

METHODS

Patients who were dispensed a [Vaughn Williams?] class I or class III antiarrhythmia drug in 1993 or 1994, but not during the two previous years, were identified from the Saskatchewan prescription drug datafile. The drug data were linked with other information that was obtained from the provincial administrative health care utilization datafiles. Further clinical data were obtained from hospital charts and, to a limited extent, from physicians' records.

RESULTS

Most patients were elderly (median age of 70 years) and were men (58.0%), although sotalol was prescribed more frequently to women (53.0%). A potential indication was identified for 63.8% of the patients and, of these, the most common was atrial fibrillation (65.3%). Almost half of the patients had a history of myocardial infarction, congestive heart failure or cardiomyopathy, and one-quarter of those were treated with amiodarone.

CONCLUSIONS

While it is not possible to prove a direct link, the results of the present study are broadly consistent with the 'evidence-based' lessons of the Cardiac Arrhythmia Suppression Trial and other studies. The increasing use of propafenone, however, may indicate a lack of appreciation for the fact that, as a class IC drug, there is at least the potential for an adverse outcome when propafenone is used in patients with structural heart disease.