Typical Atrial Flutter - When Do You Say You Have Got It

Citation : Michaël Peyrol, Pascal Sbragia

Right Atrial Flutter (AFL) is a common form of macro reentrant arrhythmia. In absence of previous cardiac surgery, the reentry circuit is usually bounded anteriorly by the tricuspid annulus (TA) and posteriorly by the ostia of vena cava and Eustachian ridge. In this case, AFL is consensually called “typical” AFL and is highly dependent of the cavotricuspid isthmus (CTI). The CTI is a critical channel which represents the predominant area of slow conduction of the circuit. Therefore, this narrow isthmus has become the universally accepted target for ablation of typical AFL. If ablation is carried out during AFL the first “intuitive” procedure endpoint is arrhythmia termination. Although this latter was initially thought to be an acceptable endpoint for ablation procedure, bidirectional CTI conduction block is actually considered as the gold standard endpoint for elimination of typical AFL recurrence. Indeed, Schumacher et al. found a 9% recurrence rate after bidirectional CTI block achievement, 54% recurrence rate after unidirectional CTI block and 100% recurrence rate when persistent slow conduction across CTI was noted after RF application on the CTI.