Do specific connection patterns of the ligament of Marshall contribute mechanistically to atrial fibrillation?

The ligament of Marshall (LOM) was first described in 1850 as a remnant of the embryonic left superior vena cava, consisting of fibrous bands, small blood vessels, and nerve elements. 1 Marshall J. On the development of the great anterior veins in man and mammalia: including an account of certain remnants of foetal structure found in the adult, a comparative view of these great veins in the different mammalia, and an analysis of their occasional peculiarities in the human subject. Phil Trans R Soc Lond. 1850; 140: 133-169 Crossref Google Scholar Elegant canine 2 Scherlag B. Yeh B. Robinson M. Inferior interatrial pathway in the dog. Circ Res. 1972; 31: 18-35 Crossref PubMed Scopus (99) Google Scholar and human 3 Hwang C. Karagueuzian H.S. Chen P.S. Idiopathic paroxysmal atrial fibrillation induced by a focal discharge mechanism in the left superior pulmonary vein: possible roles of the ligament of Marshall. J Cardiovasc Electrophysiol. 1999; 10: 636-648 Crossref PubMed Scopus (133) Google Scholar studies subsequently showed that the vein of Marshall and the LOM contain myocardial tissue—the Marshall bundle—which is electrically active and a potential cause of atrial fibrillation (AF) in canines. 4 Chen P. Wu T. Hwang C. et al. Thoracic veins and the mechanisms of non-paroxysmal atrial fibrillation. Cardiovasc Res. 2002; 54: 295-301 Crossref PubMed Scopus (74) Google Scholar Accordingly, a great deal of attention has focused on potential mechanistic contributions of the Marshall bundle to human AF, given the central role of thoracic veins such as the pulmonary veins, coronary sinus, and vena cava. Nevertheless, mechanisms linking the Marshall bundle with human AF are unclear.