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The ligament of Marshall: a structural analysis in human hearts with implications for atrial arrhythmias

D T Kim1, A C Lai, C Hwang

  • 1Department of Medicine at Cedars-Sinai Medical Center/UCLA, Los Angeles, California, USA.

Journal of the American College of Cardiology
|October 12, 2000
PubMed

Insights

The human ligament of Marshall (LOM) contains sympathetic nerves and myocardial tracts, forming a substrate for atrial tachyarrhythmias. Its complex anatomy, including insertions into the left atrium and coronary sinus, may impact ablation strategies.

Area of Science:

  • Cardiac Anatomy
  • Electrophysiology
  • Histology

Background:

  • The ligament of Marshall (LOM) is implicated in focal atrial tachyarrhythmias.
  • Detailed gross and microscopic anatomy of the human LOM is not fully understood.

Purpose of the Study:

  • To investigate the detailed anatomy of the human ligament of Marshall.

Main Methods:

  • Postmortem examination of seven human hearts.
  • Dissection of tissue encompassing the LOM from the coronary sinus.
  • Histological staining (hematoxylin and eosin, trichrome, tyrosine hydroxylase).

Main Results:

  • The LOM contains sympathetic nerve fibers, ganglia, blood vessels, and myocardial tracts (Marshall Bundles).
  • Myocardial tracts insert into the left atrial free wall and coronary sinus.
  • Nerve fibers are present within the fibrofatty matrix and myocardial tracts.

Conclusions:

  • The human LOM is innervated by sympathetic nerves and is more complex than in canines.
  • Multiple myocardial tract insertions create a substrate for reentry arrhythmias.
  • Ablation targeting the coronary sinus may miss critical free wall insertions.
Abstract

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