High-amplitude pacing can identify epicardial connections in the posterior wall during ablation for atrial fibrillation

Arshad Muhammad Iqbal; Suhaib Bajwa; Cory M. Smith; Supraja Thunuguntla; Sandeep Gautam

doi:10.1016/j.hroo.2025.09.023

October 1, 2025Heart Rhythm O2Open Access

High-amplitude pacing can identify epicardial connections in the posterior wall during ablation for atrial fibrillation

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Why the study?

Residual epicardial connections may contribute to non-durable posterior wall isolation and increased AF recurrence following ablation for persistent AF.

Does high-amplitude pacing (20 mA at 2 ms) identify residual epicardial connections and guide additional ablation to achieve complete posterior wall isolation and reduce arrhythmia recurrence in patients undergoing radiofrequency catheter ablation for persistent atrial fibrillation?

Structured PICO

Does high-amplitude pacing (20 mA at 2 ms) identify residual epicardial connections and guide additional ablation to achieve complete posterior wall isolation and reduce arrhythmia recurrence in patients undergoing radiofrequency catheter ablation for persistent atrial fibrillation?

P

Population

100 consecutive patients undergoing radiofrequency catheter ablation (PVI and posterior wall isolation [PWI]) for persistent atrial fibrillation (PersAF) at a single center (October 2021 to September 2024). In the 81 patients who underwent the high-amplitude pacing (HAP) protocol: Group A (HAP capture present without exit block, n=63) had mean age 68.3 ± 7.2 years, BMI 34.9 ± 7.9, LVEF 0.5 ± 0.13; Group B (HAP capture absent/exit block, n=18) had mean age 64.6 ± 10 years, BMI 34 ± 7.8, LVEF 0.5 ± 0.1.

I

Intervention

High-amplitude pacing (HAP; bipolar pacing at 20 mA at 2 ms with contact force ≥10 g) performed in at least 2 sites in each of 16 posterior wall segments following standard pulmonary vein isolation, roof and floor connecting lines, and segmental ablation for posterior wall entrance block (using 50 W high-power short-duration radiofrequency ablation), followed by additional targeted ablation at HAP-excitable sites without exit block.

C

Comparator

Standard bipolar pacing (SP; 10 mA at 2 ms with contact force >10 g) alone, or internal comparison between patients with HAP-only capture without exit block (Group A, n=63) versus patients with HAP non-capture or exit block (Group B, n=18).

O

Outcome

Identification of posterior wall sites excitable only with high-amplitude pacing (HAP-only capture) after standard posterior wall isolation, and achievement of final complete posterior wall isolation (defined as exit block or lack of posterior wall capture).surrogate

Limitations

Observational nature and relatively small sample size limiting generalizability
Single-center, single-operator design with potential for intraobserver error
Variability in follow-up data (28% lost to follow-up or incomplete information) and inconsistent use of long-term monitoring
Use of fixed 10 mA at 2 ms for standard pacing rather than determining preablation diastolic threshold in each segment to pace at twice the threshold
Small number of patients (12) with absent transmural PWI, precluding meaningful comparison of long-term recurrence

Implication

High-amplitude pacing (20 mA at 2 ms) during posterior wall isolation for persistent atrial fibrillation unmasks residual epicardial connections in 63% of patients that are missed by standard pacing and are associated with higher arrhythmia recurrence.

Abstract

Background PWI is a supplemental modality to PVI in RFA for persistent AF. Residual Epicardial connections may contribute to non-durable PWI and increased AF recurrence. Objective Use of novel high amplitude pacing (HAP) technique to unmask epicardial connections following PWI. Methods One hundred consecutive patients underwent PVI/PWI RFA with roof and floor lines and segmental ablation for PW entrance block. The PW was divided into 4 quadrants, each subdivided into 4 segments, labeled 1-16. Following PW entrance block, bipolar pacing was performed in each segment with standard pacing (SP) (10mA @2ms) and HAP (20mA @2ms). Exit block was defined as lack of atrial capture from within PW. Results Patients were divided into Group 1 (unable to achieve complete PWI) and Group 2 (PWI achieved). We categorized patients into subgroups based on the presence/absence of entrance blocks, captures, and exit blocks. PW entrance block was not achieved in 2 (2%) patients, 17 (17%) patients demonstrated bidirectional PW block with SP. HAP-only capture was seen in 74/81 of remaining patients. Mid-PW had the highest frequency of HAP-only capture. Additional ablation was performed in 63 HAP patients without PW exit block, with final PWI achieved in 51/63 (80.9%) patients, compared to 18/18 (100%) in the cohort with HAP non-capture/exit block (p = 0.045). Conclusion Our novel protocol of high amplitude pacing unmasked possible epicardial capture in 63% of patients, with true PWI with additional ablation in 80.9% patients. HAP may help unmask epicardial connections and facilitate durable PWI to improve long-term procedural success.

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Cite This Study

Iqbal et al. (2025) studied this question.

synapsesocial.com/papers/6a7f6831da933dc786a733c4 https://doi.org/10.1016/j.hroo.2025.09.023

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High-amplitude pacing can identify epicardial connections in the posterior wall during ablation for atrial fibrillation

Figures

Structured PICO

Limitations

Implication

Abstract

Discussion

Cite This Study

High-amplitude pacing can identify epicardial connections in the posterior wall during ablation for atrial fibrillation

Figures

Structured PICO

Limitations

Implication

Abstract

Discussion

Cite This Study

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