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Published on: November 7, 2019
Chasing Conduction Gaps Across the Roof Line: Nearby and Overlap Better Than Appendage Pacing
Takamitsu Takagi1, Osamu Inaba1, Yukihiro Inamura1
1Japanese Red Cross Saitama Hospital, Japan (T.T., O.I., Y. Inamura, A.S., Y. Isonaga, S.T., H.O.).
Insights
Nearby pacing is superior for validating roof lines during atrial fibrillation ablation compared to left appendage pacing. Overlap pacing provides a fast, effective alternative for assessing block, ensuring successful ablation outcomes.
Area of Science:
- Electrophysiology
- Cardiac Ablation
- Atrial Fibrillation Management
Background:
- Successful atrial fibrillation ablation relies on effective linear lesion creation and validation.
- Roof line block validation is crucial for achieving durable outcomes in atrial fibrillation ablation.
- Different pacing techniques may influence the accuracy of roof line block assessment.
Purpose of the Study:
- To compare the efficacy of various pacing modes for validating roof line block during atrial fibrillation ablation.
- To determine the optimal pacing strategy for identifying conduction gaps across the roof line.
- To assess the sensitivity and specificity of different pacing techniques in roof line validation.
Main Methods:
- Fifty patients undergoing atrial fibrillation ablation with roof and floor lines were studied.
- Roof line block was evaluated using high-density mapping with pacing from the left atrial appendage, near the line, or with overlapping catheters.
- Floor line block was mandatory for clear roof line evaluation, confirmed by box isolation.
Main Results:
- Roof line mapping was feasible in 100% of patients with left appendage and nearby pacing, and 90% with overlap pacing.
- Left appendage pacing showed significantly lower sensitivity (48%) and negative predictive value for block compared to nearby (97% sensitivity, 94% NPV) and overlap pacing (93% sensitivity, 89% NPV).
- Nearby pacing demonstrated superior identification of true gaps and block compared to left appendage pacing.
Conclusions:
- Nearby pacing is more effective than left appendage pacing for detecting roof line gaps due to greater activation delay.
- Overlap pacing offers a simple, fast, and effective alternative for roof line validation with performance similar to nearby pacing.
- Accurate validation of roof line block is essential for successful atrial fibrillation ablation, with pacing strategies significantly impacting gap detection.
Background:
Blocking a line depends not only on the ablation but also on the validation technique. We sought to compare the performance of different pacing modes for roof line validation.
Methods:
Fifty consecutive patients underwent atrial fibrillation ablation, which included a roof line and a floor line. Floor line block was mandatory for clear evaluation of the roof line, the block of which was demonstrated by a box isolation of the dome. Before floor line creation, first-pass roof line evaluation was based on high-density mapping while pacing from either: (1) the left appendage; (2) just above the line; or (3) with an overlapping multispline catheter.
Results:
Roof line mapping was feasible in all patients (100%) during left appendage and nearby pacing, and in 45 (90%) patients during overlap pacing. Left appendage pacing sensitivity for true gaps was significantly lower than nearby (48% versus 97%; P<0.001) and overlap (48% versus 93%; P<0.001) pacing. Left appendage pacing negative predictive value for true block was significantly lower than nearby (50% versus 94%; P=0.001) and overlap (50% versus 89%; P=0.004) pacing. Double potentials during left appendage pacing were shorter than during nearby pacing (63±20 ms versus 103±22 ms; P<0.001). In 1 patient, a slow conduction gap was unmasked only after floor line block. Final box isolation of the dome was achieved in 47 (94%) patients.
Conclusions:
The longer the activation delay from one side of a line to the other, the greater the chance to unmask a slow conduction gap across the line. Nearby pacing thus better identifies roof line gaps than left appendage pacing. Overlap pacing offers a simple and fast alternative with similar performance.
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