Drug therapy of supraventricular tachyarrhythmias--based on efficacy or futility?

The clinical spectrum of supraventricular tachyarrhythmias ranges from infrequent, brief and well tolerated episodes of arrhythmia to attacks resulting in cardiovascular collapse. Many patients have such infrequent episodes that prophylactic or ablative therapy is not indicated. In those with more troublesome symptoms, an initial trial of medical therapy is common unless the arrhythmia has major prognostic or vocational importance. Thus despite the recent advances in catheter ablation techniques, there remains a place for antiarrhythmic drug therapy in supraventricular tachyarrhythmias. Furthermore, ablation therapy in atrial fibrillation is currently unable to control arrhythmias except by destruction of the normal conduction system. In contrast to the therapy goals in ventricular tachyarrhythmias, safety considerations far outweigh those of efficacy in the drug management of supraventricular tachycardias. Many patients with supraventricular tachyarrhythmias are young and have no serious underlying heart disease. Although symptomatic recurrences of arrhythmia are troublesome, these should be regarded as acceptable if the alternative is serious drug-related toxicity. There are relatively few well conducted clinical trials of the efficacy of drug therapy in supraventricular tachycardia. Existing study data and new trial information on the efficacy of propafenone are reviewed.