January 1, 1985AJP Heart and Circulatory Physiology
Efferent vagal innervation of canine ventricle
Population
Canine model (dogs)
Comparison
Application of phenol at selected sites of the… vs Measurements before phenol application (baseline)
Design
Preclinical
Authors
Discussion
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Implication
Identifies superficial AV groove crossing for LV vagal fibers in dogs; leaves open human anatomic translation and therapeutic targeting.
Key Points
- To identify the anatomical route that efferent vagal nerve fibers travel to innervate the canine left ventricle.
- Measured left ventricular and septal effective refractory period (ERP) changes during vagal stimulation and concurrent norepinephrine infusion in canines.
- Applied epicardial phenol chemically to interrupt nerve fibers across the atrioventricular groove, within circular rings of varying radii (1 cm, 2 cm, 3 cm), and along sequential apex-to-base arcs.
- Phenol application across the atrioventricular groove completely abolished vagal-induced ERP prolongation in the anterior and posterior left ventricular free wall and partially reduced septal ERP prolongation.
- Epicardial circular phenol applications abolished vagal ERP responses in all dogs with a 3-cm radius, in 13 of 18 dogs with a 2-cm radius, and in 0 dogs with a 1-cm radius.
- Sequential arcs applied from apex to base eliminated efferent vagal actions only when painted at or adjacent to the atrioventricular groove, indicating fibers run within 0.25 to 0.5 mm of the epicardium.
Structured PICO
P
Population
Canine model (dogs)
I
Intervention
Application of phenol at selected sites of the heart (AV groove, epicardial circles of varying radii, arcs) during vagal stimulation and constant infusion of norepinephrine
C
Comparator
Measurements before phenol application (baseline)
O
Outcome
Left ventricular and septal effective refractory period (ERP) changessurrogate
The majority of efferent vagal fibers innervating the anterior and posterior left ventricular epicardium in dogs cross the AV groove superficially (within 0.25-0.5 mm of the epicardial surface).
Cite This Study
Takahashi et al. (1985) studied this question.