Another Gate Keeper to Protect the Mitral Isthmus?: Importance of the Vein of Marshall

Radiofrequency Catheter Ablation Targeting the Vein of Marshall in Difficult Mitral Isthmus Ablation or Pulmonary Vein Isolation

“…Epicardial muscular connection with the VOM may be a key reason for a high failure rate. Case reports have emphasized the importance of VOM ablation in performing a successful MI block . Hwang et al .…”

“…This technique does not require ballooning of the CS or changing sheaths, and can visualize small peripheral branches of the great cardiac vein with reduced risk of CS dissection . Although this method has been applied for the visualization of VOM in a recent case report, its feasibility and safety have not been well evaluated yet in clinical practice.…”

“…The proximal portions of the muscle tracts connect to the CS myocardial sleeves, whereas the distal portions extend upward into the PV or LA free wall . This oblique epicardial pathway may bridge over the mitral isthmus (MI) or left PV circumferential ablation line, making those lesion sets ineffective . VOM ablation may eliminate these connections and allow achieving a conduction block over the MI or left PVI ablation line.…”

“…VOM ablation may eliminate these connections and allow achieving a conduction block over the MI or left PVI ablation line. However, despite this important clinical implication, the benefit of VOM ablation has been evaluated in only a small number of subjects . In this study, we assessed the feasibility of VOM venography using an open‐irrigated RF catheter and evaluated the benefit of RF ablation targeting the VOM in cases that failed MI block or PVI.…”

Marshall bundle reentrant atrial tachycardia after the Cox‐Maze IV procedure: The last barrier of the conduction pathway between the coronary sinus and left atrium

“…Several macroreentrant ATs using the MB have been reported; these ATs were treated by ablation, which often leads to the MB conduction block [2,3]. Four methods of creating the MB conduction block have been reported: ridge ablation for disconnecting the distal MB‐LA connections [1,2], ablation inside the vein of Marshall [4], CS ablation for disconnecting the CS‐MB connections [5], and ethanol infusion [3]. In this case, the MB conduction block was created by the ridge ablation.…”