Arrhythmias & electrophysiology
Epicardial connection after radiofrequency mitral isthmus ablation
Authors' conclusion
Epicardial MB conduction frequently reconnects, even after a previous MI block creation, and is strongly associated with AT involving this connection.
Study context
- Population
- Patients undergoing repeat ablation with previously confirmed mitral isthmus conduction block after radiofrequency ablation, assessed with a vein of Marshall cathetersuccessful vein of Marshall (VOM) catheter insertion
- Participants
- 55 patients
- Outcome
- Incidence of epicardial Marshall bundle reconduction and its role as a critical isthmus for atrial tachycardia
Methodological detailsconsecutive patients
- Consecutive patients
Main finding
As reported in the abstract
- Recurrent mitral isthmus conduction
- 33 patients (60%)
- Epicardial Marshall bundle involvement among recurrences
- 31 of these (94%)
- Reconnection through endocardial mitral isthmus and coronary sinus musculature
- 17
- Reconnection exclusively through the Marshall bundle
- 14
- Exclusive epicardial reconnection serving as isthmus for reentrant atrial tachycardia
- 7 of the 14 patients (50%)
Observational data: associations, not effects.
Further findings
Atrial tachycardia using blocked Marshall bundle remnant, among patients with sustained mitral isthmus block
- Patients with sustained block including the Marshall bundle
- 22
- Atrial tachycardia using a blocked Marshall bundle remnant
- 2
Marshall bundle ablation
- Marshall bundles ablated
- 33
- Of which functioned as atrial tachycardia isthmus
- 9
- VOM ethanol infusion alone or with radiofrequency ablation eliminated all target Marshall bundle conductions
Original publication
Epicardial connection after radiofrequency mitral isthmus ablation. Heart Rhythm. Published 3 December 2025. doi:10.
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