Arrhythmias & electrophysiologyResearch article
Innervation of the Human Atrioventricular Node via the Inferior Pyramidal Space: Characterization Using Intersectional Strategies
- 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
- Seven participants
- Comparison
- anterior fat pad vs posterior fat pad
Main finding
As reported in the abstract
Course of nerve fascicles within the anterior fat pad
- 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
| Outcome | anterior fat pad | posterior fat pad | P value |
|---|---|---|---|
| Nerve fascicle thickness within the IPS · sympathetic thicker | P < 0.001 | ||
| Ganglia (mainly nonsympathetic) · predominantly within the posterior fat pad | 5.8 ± 5.0 | 63.2 ± 40.3 | P < 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
Summarised from the published abstract; every number is checked against it