Ripple Mapping-guided Atrial Tachycardia Ablation Following Open-heart Surgery: Interpretation of Reentry Circuits and Selection of Critical Isthmus

BACKGROUND Ripple mapping (RM) can make the visualization of activation conduction on a 3-dimensinal voltage map. However, its potential advantage in mapping complex atrial tachycardias (ATs) in patients after cardiac surgery has not yet been evaluated. OBJECTIVE To assess the efficacy of ripple mapping for interpreting reentrant circuits and critical isthmus in postoperative ATs. METHODS 24 consecutive patients with a history of open-heart surgery (mean age, 54.5±12.4years) underwent high density (HD) RM during ATs with CARTO3v4 CONFIDENSE system. The voltage activation threshold was determined by RM over a bipolar voltage map. Identification of underlying mechanisms and ablation setting were based on RM without reviewing activation mapping. RESULTS A total of 34 ATs (24 spontaneous, 10 induced) were characterized. 32 reentry circuits were successfully mapped (cycle length, 255±40ms). One focal AT were mapped in the left atrium (LA). Of the 34 ATs, 21 were confirmed by ripple mapping alone (62%), and 12 (32%) by ripple mapping and entrainment mapping. Of 14 ATs in the left atrium, 8 (57%) needed entrainment to confirm, compared with 3 (15%) in the right atrium. Primary endpoint after initial ablation set was achieved in 22 of the 24 patients (91.7%). Both patients were electrically converted to sinus rhythm due to unsuccessful ablation and variable tachycardia cycle length. Conclusion: Ripple mapping precisely delineated reentrant circuits in post cardiac surgery AT resulting in a high success rate of ablation. Entrainment maneuvers remain useful for elucidation of complex AT circuits.