Abstract:
The Ligament of Marshall (LOM) is a remnant of the embryonic sinus venosus and the left cardinal vein, containing a combination of fat, fibrous tissue, blood vessels, muscle bundles, nerve fibers, and ganglia. Various muscular connections exist between the LOM and the left atrium (LA) and the coronary sinus (CS). The LOM is richly innervated by autonomic nerves, with ganglion cells distributed around it. The unique characteristics of the LOM are responsible for generating focal electrical activities and enable it to serve as a substrate for micro- and macro-reentrant circuits. This, in turn, leads to the initiation and perpetuation of atrial fibrillation (AF) and atrial tachycardia (AT). Endocardial ablation in this region does not consistently succeed due to anatomical constraints within the left lateral LA, including the presence of a thicker and longer mitral isthmus (MI), anatomical variations between the MI and epicardial structures such as the CS and vein of Marshall (VOM) and circumflex artery, and the presence of fibrofatty tissue insulating the LOM. Furthermore, epicardial ablation is challenging for inexperienced institutions because of its invasive nature. Ethanol infusion into the VOM (EI-VOM) represents an effective and safe approach that can be employed in conjunction with radiofrequency ablation to eliminate this arrhythmogenic structure.
摘要:
马歇尔韧带(LOM)是胚胎窦静脉和左主静脉的残余,含有脂肪的组合,纤维组织,血管,肌肉束,神经纤维,和神经节。LOM与左心房(LA)和冠状窦(CS)之间存在各种肌肉连接。LOM由自主神经支配,周围分布着神经节细胞。LOM的独特特性负责产生焦点电活动,并使其能够用作微观和宏观折返电路的基板。这个,反过来,导致心房颤动(AF)和房性心动过速(AT)的开始和延续。由于左外侧LA内的解剖学限制,该区域的心内膜消融不能持续成功。包括更厚和更长的二尖瓣峡部(MI)的存在,MI和心外膜结构之间的解剖变异,如CS和马歇尔静脉(VOM)和回旋动脉,和纤维脂肪组织的存在使LOM绝缘。此外,心外膜消融由于其侵入性而对经验不足的机构具有挑战性。将乙醇注入VOM(EI-VOM)代表了一种有效且安全的方法,可以与射频消融结合使用以消除这种致心律失常结构。