The ligament of Marshall as a parasympathetic conduit

Joseph S. Ulphani, Rishi Arora, Jack H. Cain, Roger Villuendas, Sharon Shen, David Gordon, Firdous Inderyas, Laura A. Harvey, Alexander Morris, Jeffrey J. Goldberger, Alan H. Kadish

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

The objective of the study was to investigate the morphology, distribution, and electrophysiological profile of the autonomic fibers that innervate the ligament of Marshall (LOM). Gross anatomical dissections were performed in 10 dogs. Sections of the left vagus nerve, left stellate ganglion, and the LOM were immunostained to identify adrenergic and cholinergic nerves. Hearts were also stained for acetylcholinesterase to identify epicardial cholinergic nerves. In vivo electropyhsiological studies were performed in another 10 dogs before and after LOM ablation. The anatomical examination revealed that the LOM is innervated by a branch of the left vagus. Immunohistochemistry confirmed that these nerve bundles are predominantly cholinergic (cholinergic-to-adrenergic ratio of 12.6 ± 3.9:1). Cholinergic nerves originating in the LOM were found to innervate surrounding left atrial structures, including the pulmonary veins, left atrial appendage, coronary sinus, and posterior left atrial fat pad. Ablation of the LOM significantly attenuated effective refractory period shortening at distant sites, such as pulmonary veins and left atrial appendage, in response to vagal stimulation (vagal-induced ERP decrease in the left atrium: baseline vs. postablation = 17 vs. 4%; P = 0.0056). In conclusion, the LOM contains a predominance of cholinergic nerve fibers. Cholinergic fibers arising from the LOM innervate surrounding structures and contribute to the electrophysiological profile of the left atrium. These findings may provide a basis for the role of the LOM in the genesis and maintenance of atrial fibrillation.

Original languageEnglish (US)
Pages (from-to)H1629-H1635
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume293
Issue number3
DOIs
StatePublished - Sep 1 2007
Externally publishedYes

Keywords

  • Ablation
  • Arrhythmia (mechanisms)
  • Autonomic nervous system
  • Innervation
  • Supraventricular arrhythmia

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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  • Cite this

    Ulphani, J. S., Arora, R., Cain, J. H., Villuendas, R., Shen, S., Gordon, D., Inderyas, F., Harvey, L. A., Morris, A., Goldberger, J. J., & Kadish, A. H. (2007). The ligament of Marshall as a parasympathetic conduit. American Journal of Physiology - Heart and Circulatory Physiology, 293(3), H1629-H1635. https://doi.org/10.1152/ajpheart.00139.2007