Abstract
BACKGROUND: Posterior wall isolation (PWI) is a supplemental modality to pulmonary vein isolation in radiofrequency ablation for persistent atrial fibrillation. Residual epicardial connections may contribute to nondurable PWI and increased atrial fibrillation recurrence. OBJECTIVE: The study aimed to investigate the use of a novel high-amplitude pacing (HAP) technique to unmask epicardial connections after PWI. METHODS: 100 consecutive patients underwent pulmonary vein isolation/PWI radiofrequency ablation with roof and floor lines and segmental ablation for posterior wall (PW) entrance block. The PW was divided into 4 quadrants, each subdivided into 4 segments, labeled 1-16. After the PW entrance block, bipolar pacing was performed in each segment with standard pacing (10 mA at 2 ms) and HAP (20 mA at 2 ms). Exit block was defined as a lack of atrial capture from within PW. RESULTS: Patients were divided into groups 1 (unable to achieve complete PWI) and 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 patients (2%); 17 patients (17%) demonstrated bidirectional PW block with standard pacing. HAP-only capture was seen in 74 of the remaining 81 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 of 63 patients (80.9%) compared with 18 of 18 (100%) in the cohort with HAP noncapture/exit block (P = .045). CONCLUSION: Our novel protocol of HAP 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.