Dual-Loop Marshall Bundle-Related Atrial Tachycardia via Multiple Connections Between the Left Atrium and Marshall Bundle

An 83-year-old woman suffering from palpitations from atrial tachycardia (AT) underwent a repeat ablation procedure. Two years prior, she had undergone pulmonary vein (PV) isolation and left atrial (LA) mitral isthmus linear ablation for atrial fibrillation. An electrophysiological study (EPS) revealed stable AT with a tachycardia cycle length of 220 ms. A 2Fr hexapolar catheter was placed in the vein of Marshall and both a high-resolution activation map and entrainment pacing confirmed dual-loop AT with the Marshall bundle (MB) as a common isthmus (Figure A; Supplementary Movie). An 11.7-s radiofrequency application at the common isthmus from the endocardial left ridge terminated the AT. Soon after the termination, high-resolution activation map during MB pacing confirmed 3 MB-LA connections (left ridge, carina between the left PVs, and posterolateral LA behind the mitral isthmus linear block line) (Figure B). After additional applications at the left ridge and re-isolation of the left PVs, a single MB-LA connection remained in the posterolateral LA but the other connections were eliminated (Figure C).

Figure.

(A) High-resolution activation maps of the dual-loop Marshall bundle (MB)-related atrial tachycardia (AT) (Left panel: anteroposterior view, Right panel: left posterior view) are shown and the numbers indicate the (post pacing interval) – (tachycardia cycle length). (B) Soon after termination of the AT, the high-resolution activation map during pacing from the MB revealed 3 MB-LA connections. (C) After additional applications, the high-resolution activation map during pacing from the MB revealed a single MB-LA connection. CS, coronary sinus; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; MA, mitral annulus; RSPV, right superior pulmonary vein; VOM, vein of Marshall.

A previously reported EPS further confirmed the presence of multiple MB-LA connections in approximately 50% of patients.¹ To our knowledge, this is the first case of dual-loop MB-related AT via 3 MB-LA connections identified by MB pacing and confirmed by high-density mapping.

Disclosures

S.M. belongs to the endowed departments of Medtronic, Boston, Abbott, and Japan Lifeline. H.T. is a member of Circulation Journal’s Editorial Team.

Acknowledgment

We thank Mr. John Martin for his help in the preparation of the manuscript.

Supplementary Files

Supplementary Movie. (A) High-resolution activation maps of the dual-loop MB-related atrial tachycardia (AT). (B) Intracardiac electrograms recorded on the vein of Marshall (VOM) and coronary sinus (CS) during the MB-related AT.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-21-0398

Reference

• 1.   Han S, Joung B, Scanavacca M, Sosa E, Chen PS, Hwang C. Electrophysiological characteristics of the Marshall bundle in humans. Heart Rhythm 2010; 7: 786–793.