Atrial Flutter, Typical and Atypical: A Review

Abstract

Clinical electrophysiology has made the traditional classification of rapid atrial rhythms into flutter and tachycardia of little clinical use. Electrophysiological studies have defined multiple mechanisms of tachycardia, both re-entrant and focal, with varying ECG morphologies and rates, authenticated by the results of catheter ablation of the focal triggers or critical isthmuses of re-entry circuits. In patients without a history of heart disease, cardiac surgery or catheter ablation, typical flutter ECG remains predictive of a right atrial re-entry circuit dependent on the inferior vena cava–tricuspid isthmus that can be very effectively treated by ablation, although late incidence of atrial fibrillation remains a problem. Secondary prevention, based on the treatment of associated atrial fibrillation risk factors, is emerging as a therapeutic option. In patients subjected to cardiac surgery or catheter ablation for the treatment of atrial fibrillation or showing atypical ECG patterns, macro-re-entrant and focal tachycardia mechanisms can be very complex and electrophysiological studies are necessary to guide ablation treatment in poorly tolerated cases.