This report provides an overview of the safety and efficacy of flecainide for supraventricular tachyarrhythmias (SVT) based on a review of the world literature. This review provided 107 entries, but 5 were review articles and 22 were articles not translated into English. The remaining 80 articles or published abstracts form the basis for this report. A total of 1,371 courses of therapy with intravenous or oral flecainide, or both, were represented. Efficacy was defined by each investigator. Intravenous flecainide was successful in terminating ongoing tachycardias in 81% of reported cases of atrioventricular (AV) nodal reentrant tachycardias, 88% of AV reentrant tachycardias and 100% of atrial tachycardias. Atrial fibrillation or flutter was terminated by intravenous flecainide in 62% of cases and arrhythmias associated with Wolff-Parkinson-White syndrome in 73%. Oral flecainide was successful in longer-term management of arrhythmia in 74 and 81% of patients with AV nodal and AV reentrant tachycardia, respectively, and in 83% with atrial tachycardia. Atrial flutter or fibrillation responded to oral drug in 61% of cases and arrhythmias related to Wolff-Parkinson-White syndrome in 61%. Adverse experiences were reported in studies totaling 695 patients (designated "at-risk patients"). They were not commented on in studies with the remaining 594 patients. Overall, a total of 6.9% of at-risk patients (3.7% of total patients) reported cardiac adverse experiences; 19% of at-risk patients (10% of total patients) reported at least 1 noncardiac adverse effect. Cardiac adverse events included worsened arrhythmias in 28, conduction disturbances in 15 and congestive heart failure in 5. The most frequent noncardiac adverse experiences were paresthesia and visual disturbance.(ABSTRACT TRUNCATED AT 250 WORDS)