Dual-Loop Intra-Atrial Reentry in Humans

Abstract

Background-Dual-loop atrial reentrant tachycardias have not been clinically described. Methods and Results-Five patients (3 men, 2 women; mean age, 48Ϯ16 years) were studied 24Ϯ15 years after surgical closure of an ostium secundum atrial septal defect for drug-resistant atrial tachycardia. Complete tachycardia mapping was performed in the right atrium with multipolar catheters and a 3-dimensional electroanatomic mapping system (Biosense), followed by linear radiofrequency ablation of the narrowest part of each complete loop. Six tachycardias with a typical flutter morphology, a cycle length of 262Ϯ40 ms, and a superior f-wave axis (Ϫ77Ϯ11°) were mapped, 4 with a Biosense map including 106Ϯ32 points. Five figure-8 tachycardias had a counterclockwise loop around the tricuspid valve sharing a common anterior channel with a clockwise loop around the lateral atriotomy scar. One tachycardia was thought to have 2 counterclockwise loops around the same obstacles. Radiofrequency delivery in the cavotricuspid isthmus in each case transformed the tachycardia without any pause in a different morphology tachycardia with an inferior P-wave axis (50Ϯ42°) and nearly the same cycle length (272Ϯ39 ms) but with the periatriotomy loop alone. This arrhythmia required ablation of a second isthmus: between the lower end of the atriotomy and the inferior vena cava in 4 and the superior tricuspid annulus in 1. After a follow-up of 19Ϯ6 months, there were no recurrences. Figure- Conclusions-

Activation Patterns and Conduction Velocity in Posterolateral Right Atrium During Typical Atrial Flutter Using an Electroanatomic Mapping System

“…7,8 Thus, there may be the complication of another loop reentry, together with typical AFL rotation around the TA. Furthermore, the other loop reentry would travel across the line between the SVC and IVC in the posterolateral wall of the RA, and this has been confirmed by conventional electrophysiological methods, 9 electroanatomic mapping 10 and, recently, by noncontact mapping. 7,8 The pattern of propagation across the posterolateral RA has been studied using virtual electrograms, 8 but the conduction patterns and conduction velocity (CV) across the CT during typical AFL, as seen on actual electrograms, are not completely understood.…”

Characterization of Reentrant Circuits in Left Atrial Macroreentrant Tachycardia

“…[1][2][3][4][5][6][7] A recent study has reported that left atrial macroreentrant tachycardia (LAMRT) can be successfully abolished by radiofrequency (RF) linear lesion in most patients, 7 but the critical isthmus was not delineated in detail. The aims of this study were (1) to describe the electroanatomic characteristics of the reentry circuit in patients with LAMRT, (2) to assess the effect of RF lesions on the critical isthmus and the conduction block across the isthmus, and (3) to investigate atrial tachycardia recurrence in patients after successful ablation.…”

ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias—Executive Summary

“…The resulting arrhythmias are referred to as "lesion-related macrore-entrant ATs." 113,[172][173][174][175] Although CTI-dependent flutter is the most common underlying mechanism in these circumstances, it often coexists with incisional macro-re-entrant ATs, resulting in multiple re-entry circuits.…”

“…Cavotricuspid isthmus-dependent flutter is common in patients with prior atrial surgery, and both CTI-and non-CTI-dependent macro-reentry circuits often coexist in a single patient. 173,[176][177][178][179][180] Successful ablation is dependent on identifying a critical portion of the re-entry circuit where it can be interrupted with either one or a line of RF applications.…”

“…113,172,173,[176][177][178][179][180][181][182][183] The incision is often placed in the lateral right atrium; the re-entry wavefront circulates around the incision. A line of ablation lesions extending from the inferior margin of the scar to the inferior vena cava, or from the superior margin of the scar to the SVC, can interrupt the circuit, but it can also be difficult to complete.…”