Noncontact Electroanatomic Mapping to Characterize Typical Atrial Flutter: Participation of Right Atrial Posterior Wall in the Reentrant Circuit

Reentrant Circuit of Typical Atrial Flutter. Background: Reentry utilizing cavotricuspid isthmus (CTI) is accepted as the mechanism underlying typical atrial flutter (AFLT). However, it is unclear how the right atrial (RA) posterior wall (PW) participates in AFLT circuit. We sought to investigate this by using noncontact electroanatomic mapping. Methods: Fifteen patients (pts) undergoing ablation for typical AFLT participated. Multipolar catheters were deployed in RA and coronary sinus. RA shell was created during AFLT. Entrainment was performed to confirm CTI dependence and assess participation of various RA regions (septum‐Sep, PW, lateral wall‐LW). Data were analyzed for (1) RA activation patterns and (2) conduction time (CT) through various RA regions. Results: Mean pt age was 70 ± 13 years (all males; CCW = 10; CW = 5). Mean AFLT cycle length was 255 ± 15 ms. Single activation wave front traversing sequentially CTI, Sep, and LW was seen in all pts and in 12 (80%; 9 CCW, 3 CW) this also traversed PW. Entrainment confirmed PW participation in 7 of these. Mean CT (in ms) through various RA regions was as follows: CTI = 69 ± 27, Sep = 50 ± 39, PW = 65 ± 35, and LW = 76 ± 35; P = NS. Conclusion: These observations offer new insights regarding the participation of PW in the reentrant circuit of typical AFLT in some patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 422‐430)