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Updated: May 24, 2026
Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation
Published on: February 26, 2013
Histopathologic characterization of chronic radiofrequency ablation lesions for pulmonary vein isolation
Marcin Kowalski1, Margaret M Grimes, Francisco J Perez
1Department of Clinical Cardiac Electrophysiology, Virginia Commonwealth University Medical Center, Richmond, Virginia, USA.
Objectives:
This study describes the histopathologic and electrophysiological findings in patients with recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation who underwent a subsequent surgical maze procedure.
Background:
The recovery of PV conduction is commonly responsible for recurrence of AF after catheter-based PV isolation.
Methods:
Twelve patients with recurrent AF after acutely successful catheter-based antral PV isolation underwent a surgical maze procedure. Full-thickness surgical biopsy specimens were obtained from the PV antrum in areas of visible endocardial scar. Before biopsy, intraoperative epicardial electrophysiological recordings were taken from each PV using a circular mapping catheter.
Results:
Twenty-two PVs were biopsied from the 12 patients 8 ± 11 months after ablation. Eleven of the 22 specimens (50%) revealed transmural scar, and 11 (50%) showed viable myocardium with or without scar. Each biopsy specimen demonstrated evidence of injury, most commonly endocardial thickening (n = 21 [95%]) and fibrous scar (n = 18 [82%]). Seven of the 22 specimens (32%) showed conduction block at surgery. Transmural scar was more likely to be seen in the biopsy specimens from the PVs with conduction block than in specimens from the PVs showing reconnection. However, viable myocardium alone or mixed with scar was seen in 2 specimens from PVs with conduction block.
Conclusions:
PVs showing electrical reconnection after catheter-based antral ablation frequently reveal anatomic gaps or nontransmural lesions at the sites of catheter ablation. Nontransmural lesions are noted in some PVs with persistent conduction block, suggesting that lesion geometry may influence PV conduction. The histological findings show that nontransmural ablation can produce a dynamic cellular substrate with features of reversible injury. Delayed recovery from injury may explain late recurrences of AF after PV isolation.
Insights
Recurrent atrial fibrillation (AF) after pulmonary vein isolation is often due to incomplete lesions. Histopathology reveals that nontransmural ablation sites can lead to viable myocardium and delayed recovery, explaining AF recurrence.
Area of Science:
- Cardiology
- Electrophysiology
- Surgical Procedures
Background:
- Pulmonary vein (PV) conduction recovery is a primary cause of atrial fibrillation (AF) recurrence post-PV isolation.
- Catheter-based PV isolation aims to create durable lesions for AF management.
Purpose of the Study:
- To investigate histopathologic and electrophysiologic findings in patients with recurrent AF after PV isolation who underwent surgical maze procedures.
- To correlate tissue characteristics with electrical conduction properties at the PV antrum.
Main Methods:
- Twelve patients with recurrent AF underwent surgical maze procedures after prior catheter-based PV isolation.
- Full-thickness PV antrum biopsies were obtained, and intraoperative epicardial electrophysiological recordings were performed.
- Histopathologic analysis focused on endocardial scar, transmurality, and cellular injury.
Main Results:
- Fifty percent of biopsied PV specimens showed transmural scar, while the other 50% exhibited viable myocardium.
- Evidence of injury, including endocardial thickening and fibrous scar, was common.
- Conduction block was observed in 32% of specimens; transmural scar was more frequent in blocked PVs, but viable myocardium was also present in some blocked sites.
Conclusions:
- Electrical reconnection in PVs after ablation often results from anatomic gaps or nontransmural lesions.
- Nontransmural lesions, even with conduction block, suggest lesion geometry influences PV conduction.
- Histology indicates that nontransmural ablation can create a substrate of reversible injury, potentially explaining late AF recurrences.
