Selective stimulation of parasympathetic nerve fibers to the human sinoatrial node.

Abstract

Electrical stimulation of parasympathetic nerve fibers in a fat pad near the sinoatrial node increased atrial cycle length without affecting atrioventricular nodal conduction. This is the first study in which such nerve fibers that innervate the sinoatrial node have been selectively stimulated in humans.

Heart function influenced by selective mid-cervical left vagus nerve stimulation in a human case study

“…[1][2][3] Accordingly, vagus nerve stimulation (VNS) has been proposed as a method for treating various heart conditions, including hypertension and heart failure.…”

Gross and microscopic anatomy of the human intrinsic cardiac nervous system

“…The full extent of the distribution of intrinsic cardiac neurons on the human heart and the synaptology of the intrinsic cardiac ganglia remains unknown. Because the functional properties of human intrinsic cardiac neural elements are now amenable to investigation (Murphy et al, 1985;Carlson et al, 1992;Murphy and Armour, 1992), it is imperative that the locations and connectivity of human cardiac neurons be determined.…”

Botulinum Neurotoxin A Blocks Cholinergic Ganglionic Neurotransmission in the Dog Heart

“…1 and 2). Parasympathetic nerve fibers selectively innervate either the sinoatrial or the atrioventricular nodal regions, and those nerve fibers pass through discrete epicardial fat pads in dog hearts (10,11,15,16), and similarly in human hearts (9). In each fat pad, there are many parasympathetic ganglionic cells as well as parasympathetic nerve fibers (15 -17).…”

“…Heart rate is decreased by acetylcholine released from the parasympathetic nerve terminals that are activated by the impulses mediated through the parasympathetic ganglia in the heart. In humans (9) as well as dogs (10 -12), almost all parasympathetic inputs that influence the heart rate pass through the parasympathetic ganglionic cells in the sinoatrial (SA) fat pad that overlies the right atrial junction of the right pulmonary veins in the heart. Stimulation of the parasympathetic neural elements in the SA fat pad decreases atrial rate and may cause sinus arrest in the dog heart (12).…”