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