Electrophysiological characteristics of the Marshall bundle in humans

Abstract

BACKGROUND Marshall bundles (MBs) are the muscle bundles within the ligament of Marshall. OBJECTIVE This trial sought to the electrophysiological characteristics of the MB and the anatomical connections between MB and left atrium (LA) in patients with persistent atrial fibrillation (AF). METHODS We enrolled 72 patients (male:female 59:13, age 59.9 ± 9.4 years) who underwent MB mapping and ablation for AF. MB mapping was done via an endocardial or epicardial approach during sinus rhythm and AF. RESULTS Recordings were successful in 64 of 72 patients (89%). A single connection was noted in 11 of 64 patients between the MB and the coronary sinus (CS) muscle sleeves. The MB recordings showed distinct MB potentials with a proximal-to-distal activation pattern during sinus rhythm. During AF, organized passive activations and dissociated slow MB ectopic activities were commonly observed in this type of connection. Double connections to both CS and LA around left pulmonary veins were noted in 23 of 64 patients (36%). After the ablation of the distal connection, MB recording showed typical double potentials as in single connection. Multiple connections were noted in 30 of 64 patients (47%). During sinus rhythm, the earliest activation was in the middle of the MB. The activation patterns were irregular and variable in each patient. During AF, rapid and fractionated complex activations were noted in all patients of this group. CONCLUSION We documented 3 different types of MB–LA connections. Rapid and fractionated activations were most commonly observed in the MB that had multiple LA connections.

Atrial Coronary Arteries in Areas Involved in Atrial Fibrillation Catheter Ablation

“…16 -21 Additionally, the role of venous structures, such as the coronary sinus and the Marshall bundle and vein, during AF RF ablation has been studied extensively. [25][26][27][28] The present work was not designed to evaluate the effects of RF near atrial arteries and limits itself to describing their presence at AF ablation sites. Nonetheless, on the basis of the existing data, it is plausible to suppose that interactions likely occur between the RF application on the endocardial surface and the subjacent artery on the subepicardial surface because of the relatively small thickness of the atrial wall.…”

2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design

“…The juncture between the great cardiac vein and the CS is marked by the entrance of the vein of Marshall (which is typically obliterated in adults and is referred to as the ligament of Marshall), which descends along the epicardium between the LAA and the LSPV and can contain sympathetic nerves and ganglia. 78 Especially around the CS itself, muscular bundles are present that interconnect to the LA, thereby serving as additional interatrial electrical “conductors.” 79,80 …”

Ligament and vein of Marshall: A therapeutic opportunity in atrial fibrillation

“…10 Discrete connections were first presented by Kim et al 3 in human specimens. In vivo in humans, Han et al documented three different types of MB-LA connections in 72 patients who underwent MB mapping and ablation for AF: 13 CS junction, LA-left PVs junction, and LA in between CS and PVs with wide multiple connections. Interestingly, rapid and fractionated activations were most commonly observed in the MB that had multiple LA connections.…”