Issues in the selection of an antiarrhythmic agent

The approach to patients with cardiac arrhythmias involves four steps: diagnosis, determination of whether therapy is needed, choice of appropriate treatment, and evaluation of efficacy of therapy. Factors affecting the decision to treat a patient include the presence and type of symptoms associated with the tachyarrhythmia, as well as the frequency with which the arrhythmia occurs. Antiarrhythmic drugs are usually recommended as first-line therapy although nonpharmacologic approaches are preferable in certain specific situations. There are minimal data for most arrhythmias that aid the physician in the selection of a specific drug for a given patient, and many agents will often be equally effective. Most often drugs are selected that have the least potential to produce harmful side effects to the patient; thus, choice of therapy must be individualized. Newer agents are effective but their antiarrhythmic and side effect profiles will not be understood fully until they have been used widely in diverse patient populations. Regardless of which drug is prescribed, invasive or noninvasive methods should be employed to evaluate therapeutic efficacy.