Nerve
Cardiac plexus
Autonomic and sensory routes entering the heart
High-yield
Sympathetic activity generally increases rate, conduction and contractile strength. Vagal activity slows nodal rate and conduction. Neither system replaces the heart's intrinsic pacemaker cells.
Overview
Sympathetic cardiac nerves and vagal branches interconnect near the great vessels before reaching the heart. This variable network distributes signals to cardiac muscle, nodal tissue and smaller intrinsic nerve networks.
Reference facts
- Origin
- Postganglionic fibers from cervical and upper thoracic sympathetic ganglia, together with vagal cardiac branches
- Root value
- Sympathetic preganglionic origin around T1–T5; parasympathetic input through cranial nerve X
- Course
- Interconnecting nerves near the aortic arch and tracheal bifurcation continue toward the heart; superficial and deep divisions are conventional descriptions
- Motor
- Sympathetic stimulation generally accelerates rate and conduction and increases contractility; vagal stimulation slows sinoatrial and atrioventricular nodal activity
- Sensory
- Spinal afferents commonly accompany sympathetic pathways; vagal afferents participate in cardiovascular reflex signaling
Clinical correlation
Cardiac visceral signals can be perceived away from the heart, including in the chest or upper limb. The varied pattern of referred symptoms means their presence or absence alone cannot identify or exclude myocardial ischemia.
Frequently asked questions
What type of nerve is the cardiac plexus?
Sympathetic preganglionic origin around T1–T5; parasympathetic input through cranial nerve X.
What muscles does the cardiac plexus supply?
Sympathetic stimulation generally accelerates rate and conduction and increases contractility; vagal stimulation slows sinoatrial and atrioventricular nodal activity.
What is the sensory distribution of the cardiac plexus?
Spinal afferents commonly accompany sympathetic pathways; vagal afferents participate in cardiovascular reflex signaling.
What is the course of the cardiac plexus?
Interconnecting nerves near the aortic arch and tracheal bifurcation continue toward the heart; superficial and deep divisions are conventional descriptions.