Macro-reentrant Single-loop Biatrial Flutter Appearing as Typical Atrial Flutter: Case Study and Review

Biatrial flutter is a rare form of macro-reentrant atrial tachycardia that involves both the right and left atria. Single-loop biatrial flutter is typically associated with scarring of the septum from prior ablation or surgery and is generally made up of two interatrial connections—that is, the coronary sinus and Bachmann’s bundle. Entrainment and high-density mapping allow for rapid diagnosis and development of a treatment strategy. Ablation planning should also take into consideration the preservation of interatrial conduction. We herein discuss a case of single-loop biatrial flutter presenting as a typical atrial flutter and review the differential diagnosis and physiology of the arrhythmia.