COEXISTENCE OF ATRIAL TACHYCARDIA AND COMMON ATRIAL-FLUTTER - ELECTROPHYSIOLOGIC CHARACTERISTICS AND RADIOFREQUENCY CATHETER ABLATION

Four patients, who had no prior atrial surgery, underwent radiofrequen cy ablation for clinically documented typical atrial flutter. In addit ion to typical atrial flutter re-entrant atrial tachycardia was initia ted during electrophysiological study in these four patients. We used earliest atrial endocardial activation and concealed entrainment pace mapping with short stimulus-P interval (< 40 ms) to identify the exit site of slow conduction area of atrial flutter and atrial tachycardia. The exit sites of slow conduction area of atrial flutter were located at the posteromedial right atrium between the coronary ostium and the tricuspid annulus and those of slow conduction area of atrial tachyca rdia were located at high lateral right atrium in all four patients. R adiofrequency energy applied to these exit sites successfully eliminat ed both atrial flutter and atrial tachycardia in these four patients. Typical atrial flutter and re-entrant atrial tachycardia with two dist inct re-entrant circuits concomitantly occurring in patients without p rior atrial surgery are rare. Radiofrequency ablation can abolish both atrial tachyarrhythmias in the same ablation session.