Impact of the post-encircling mapping (PEM) protocol on procedural efficiency and arrhythmia-free outcomes after atrial fibrillation redo ablation

Background

Post-encircling mapping (PEM) combines distal coronary sinus pacing with high-density activation mapping of the left atrium (LA) to identify residual entrance conduction gaps after previous pulmonary vein isolation (PVI). Its effect on procedural efficiency and clinical outcomes in atrial fibrillation (AF) redo ablation remains uncertain.

Purpose

To evaluate the effect of the PEM protocol on procedural performance and arrhythmia-free survival in AF redo procedures compared with conventional bipolar mapping.

Methods

Eighty-four consecutive patients undergoing AF redo ablation (2017–2025) were retrospectively analyzed. Procedures performed before PEM protocol implementation (n = 34) were compared with those performed using the PEM protocol (n = 50).

Primary procedural endpoints were first-pass PVI and total radiofrequency (RF) time; secondary endpoints included LA dwelling time, total procedure and fluoroscopy duration, and acute complications.

Clinical outcomes were assessed in 62 patients with available follow-up (25 non-PEM, 37 PEM), including sinus rhythm (SR) maintenance, AF recurrence, and left ventricular ejection fraction (LVEF).

Comparisons used Mann–Whitney U or χ² tests; multivariate logistic and linear regression adjusted for age, sex, AF subtype, and type of ablation catheter used.

Results

PEM was associated with shorter RF time at univariate analysis (529 [51–1007] sec vs 1481 [762–2201] sec, p < 0.001), but this effect was attenuated after adjustment (β = –268 s, p = 0.22) owing to collinearity with very high-power-short duration (VHPSD) catheters, which independently reduced RF time (β = –1004 s, p < 0.001).

PEM also correlated with shorter LA dwelling (55 [42–69] min vs 100 [73–128] min, p < 0.001), skin-to-skin (125 [100–150] vs 155 [123–188] min, p = 0.007) and fluoroscopy times (9.0 [6.0–12.0] vs 12.0 [6.5–17.5] min, p = 0.016). Complication rates were low and comparable (4.8%).

At a median 22-month follow-up, SR maintenance was more frequent after PEM (89.5 % vs 72.0 %), and PEM independently predicted SR maintenance (OR 25.8, p = 0.006) after adjustment for AF subtype and follow-up duration. However, Kaplan–Meier analysis showed no significant difference in freedom from AF recurrence between PEM and non-PEM groups (median 32 vs 69 months, log-rank p = 0.50).

Conclusions

PEM-guided gap assessment during AF redo ablation improved procedural efficiency, reducing unnecessary RF delivery and LA dwelling without increasing complications.

Although Kaplan–Meier survival did not show a statistically significant difference in AF recurrence, PEM remained an independent predictor of SR maintenance, supporting its integration into contemporary redo AF ablation workflows.