Regional distribution of atrial electrical changes induced by stimulation of extracardiac and intracardiac neural elements.
Autonomic nerves and intrinsic cardiac neural elements are known to influence the electrophysiologic and dynamic properties of the heart. This study describes the regional distribution in the canine atria of electrophysiologic effects induced by stimulation of the right and left cervical vagosympathetic complexes, the right atrial ganglionated plexus, and the right and left stellate ganglia. Local atrial effects were determined from changes in QRST area of unipolar electrograms recorded from multiple sites with plaque electrodes sewn onto the atria in 16 anesthetized dogs.


RESULTS
(1) Although being very consistent in any given preparation, atrial changes varied between animals when similar neural structures were stimulated. (2) Among the common features identified between preparations, consistent effects were induced by neural stimulation in the region of the sinus node, indicating that this atrial region is the most richly innervated. (3) All other regions of the atria could be affected by stimulation of either right-sided or left-sided efferent nerves. (4) Responses to right atrial ganglionated plexus stimulation after atropine administration indicated that the corresponding fat pad contains both sympathetic and parasympathetic neural elements.


CONCLUSIONS
This study demonstrates that there is considerable overlapping of atrial innervation affecting all regions of the atria, as well as the sinus node region.
Centre de Recherche de l'Hôpital du Sacré-Coeur de Montréal, Quebec, Canada.
P L
PL
Pagé
N
N
Dandan
P
P
Savard
R
R
Nadeau
J A
JA
Armour
R
R
Cardinal
D000818:Animals; D016275:Atrial Function; D001341:Autonomic Nervous System / Q000033:anatomy & histology / Q000502:physiology*; D002304:Cardiac Pacing, Artificial; D004285:Dogs; D004525:Efferent Pathways / Q000502:physiology; D004558:Electric Stimulation; D004562:Electrocardiography; D004567:Electrodes, Implanted; D004594:Electrophysiology; D005728:Ganglia, Sympathetic / Q000502:physiology; D006325:Heart Atria / Q000294:innervation*; D012849:Sinoatrial Node / Q000294:innervation* / Q000502:physiology; D013233:Stellate Ganglion / Q000502:physiology