Relationship Between Nonuniform Isochrone‐Area in Late Activation Mapping and Arrhythmogenic Substrates Related to Atrial Fibrillation
Tomonori Watanabe, Masashi Kamioka, Hisaki Makimoto, Takafumi Okuyama, Hiroaki Watanabe, Ayako Yokota, Takahiro Komori, Tomoyuki Kabutoya, Hitoshi Hachiya, Yasushi Imai, Kazuomi KarioABSTRACT
Introduction
Arrhythmogenic substrates within the atrial myocardium may contribute to the initiation of atrial fibrillation (AF). The relationship between nonuniform isochrone‐areas in late activation mapping and arrhythmogenic substrates remains undetermined.
Methods
Sixty‐two patients (66 ± 10 years, 47 males, non‐paroxysmal AF [ n = 30], second ablation procedure [ n = 8]) who undergoing catheter ablation for AF were enrolled. High‐density left atrial (LA) activation mapping was performed during atrial pacing after pulmonary vein (PV) isolation. Late activation mapping was retrospectively reconstructed. Nonuniform isochrone‐areas were defined as regions of nonuniform and mottled conduction‐zones characterized by the crowding of ≥ 3 color‐isochrones within a 1‐cm radius in late activation mapping. The relationship between nonuniform isochrone‐areas and arrhythmogenic substrates associated with AF was evaluated.
Results
Non‐PV triggers were identified in 11 patients (AF‐triggers:12; short runs of premature atrial complexes:4), located in the LA wall (posterior:7; anterior:6; septum:2; roof:1). Patients with non‐PV triggers had significantly more nonuniform isochrone‐areas than those without (median [interquartile range] 5.0 [3.0–6.0] vs. 2.0 [1.0–4.0], p < 0.001). In multivariate logistic analysis for the presence of non‐PV triggers, after adjusting for confounders such as non‐paroxysmal AF, heart failure‐history, and presence of low‐voltage areas, the presence of nonuniform isochrone‐areas on the LA low‐posterior wall was an independent indicator for the presence of non‐PV triggers (odds ratio: 6.9 [95% CI:1.1–44.1], p = 0.040). Of the 52 nonuniform isochrone‐areas observed in the 11 patients with non‐PV triggers, 20 areas corresponded to non‐PV trigger sites.
Conclusion
Identification of nonuniform isochrone‐areas located on LA low‐posterior wall in late activation mapping may indicate the potential source for non‐PV triggers.