Arrhythmias & electrophysiology

Innervation of the Human Atrioventricular Node via the Inferior Pyramidal Space: Characterization Using Intersectional Strategies

Circ Arrhythm ElectrophysiolPublished whole-mount tissue-clearing method with immunohistochemical staining

Authors' conclusion

The human IPS exhibits a distinct pattern of autonomic innervation and distribution of ganglia. These neural structures are likely to contribute to the physiological control of the human AVN and could be a novel target for neuromodulation to restore normal AVN function.

Study context

Population
Whole-mount samples of the human inferior pyramidal space (IPS) involving the atrioventricular node (AVN) from hearts rejected for transplantationwhole-mount samples of the human IPS involving the AVN (85.7% male, 49.4±12.8 years old)
Participants
7 participants
Comparison
Anterior fat pad vs posterior fat pad
Outcome
Course of nerve fascicles within the anterior fat pad

Main finding

As reported in the abstract

  • Sympathetic nerve fascicles ascended towards the AVN along the AVN artery, whereas nonsympathetic nerve fascicles approached the AVN from the superior and posterior aspects without a consistent relationship to the AVN artery

Further findings

OutcomeAnterior fat padPosterior fat padP value
Nerve fascicle thickness within the IPSSympathetic nerve fascicles vs nonsympathetic nerve fascicles · sympathetic thickerP < 0.001
Ganglia (mainly nonsympathetic)Predominantly within the posterior fat pad5.8 ± 5.063.2 ± 40.3P < 0.01
  • Nerve fascicle thickness within the IPS: sympathetic nerve fascicles 51.7 ± 32.8 µm
  • Nerve fascicle thickness within the IPS: nonsympathetic nerve fascicles 22.1 ± 10.6 µm

Compact AVN regions

Devoid of thick nerve fascicles and ganglionated plexuses but filled with a fine meshwork of both sympathetic and nonsympathetic nerve fibers

Original publication

Innervation of the Human Atrioventricular Node via the Inferior Pyramidal Space: Characterization Using Intersectional Strategies. Circ Arrhythm Electrophysiol. Published 29 July 2026. doi:10.1161/circep.126.014978

Composed by AI from the published abstract and checked against it. How Briefs are made →

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