Typical Atrial Flutter: A Practical Review

Typical atrial flutter (AFL), defined as cavotricuspid isthmus (CTI)-dependent macro-re-entrant atrial tachycardia, often causes debilitating symptoms, and is associated with increased incidence of atrial fibrillation, stroke, heart failure, and death. Typical AFL occurs in patients with atrial remodeling and shares risk factors with atrial fibrillation. It is also common in patients with a history of prior heart surgery or catheter ablation. It is characterized by a recognizable ECG pattern that is highly predictive of CTI-dependent re-entry in patients without iatrogenic atrial scars. Typical AFL is difficult to manage medically due to poor efficacy of rate-controlling and antiarrhythmic drugs. Catheter ablation has been established in randomized trials to be superior to medical management in terms of safety, efficacy, and clinical outcomes including hospitalization and quality of life. Catheter ablation aims at achieving bidirectional conduction block across the CTI, which can be efficiently assessed by well-established techniques such as differential pacing. Long-term ablation success requires creating a stable transmural and continuous lesion, which can be optimized by systematic assessment of ablation parameters and lesion contiguity. The present review discusses the epidemiology, mechanisms, ECG characteristics, medical management, and catheter ablation of typical AFL.