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Published on: July 29, 2011
Relationship Between Nonuniform Isochrone-Area in Late Activation Mapping and Arrhythmogenic Substrates Related to
Tomonori Watanabe1, Masashi Kamioka1, Hisaki Makimoto1
1Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Tochigi, Japan.
Insights
Non-uniform isochrone-areas in late activation mapping may indicate non-pulmonary vein triggers in atrial fibrillation (AF) patients. This finding aids in identifying potential arrhythmogenic sources during ablation procedures.
Area of Science:
- Electrophysiology
- Cardiac Mapping
- Atrial Fibrillation Pathophysiology
Background:
- Arrhythmogenic substrates in the atrial myocardium can initiate atrial fibrillation (AF).
- The link between nonuniform isochrone-areas in late activation mapping and these arrhythmogenic substrates is not well understood.
Purpose of the Study:
- To investigate the relationship between nonuniform isochrone-areas identified through high-density mapping and the presence of arrhythmogenic substrates in patients undergoing AF ablation.
- To determine if these mapped areas are predictive of non-pulmonary vein (PV) triggers.
Main Methods:
- Sixty-two patients undergoing AF catheter ablation had high-density left atrial (LA) activation mapping post-pulmonary vein isolation.
- Late activation mapping was reconstructed, defining nonuniform isochrone-areas as regions with ≥3 color-isochrones within a 1-cm radius.
- The association between these areas and AF triggers was evaluated.
Main Results:
- Non-PV triggers were found in 11 patients, often located on the LA wall.
- Patients with non-PV triggers exhibited significantly more nonuniform isochrone-areas compared to those without (median 5.0 vs. 2.0).
- Nonuniform isochrone-areas on the LA low-posterior wall independently predicted the presence of non-PV triggers (OR: 6.9).
Conclusions:
- Identification of nonuniform isochrone-areas on the LA low-posterior wall during late activation mapping can suggest potential sources of non-PV triggers.
- This mapping technique may help localize arrhythmogenic substrates contributing to AF initiation.
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.
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