Foundations of Neurocardiology: Neural control of the normal and diseased heart

Abstract

Neurons in the intrinsic cardiac and intrathoracic extracardiac networks of the cardiac neuronal hierarchy form distinct nested feedback loops that act in concert with central feedback loops in the spinal cord, medulla and higher centers to coordinate regional cardiac function. Intrathoracic ganglia contain afferent, local circuit (interneurons) and sympathetic efferent postganglionic neurons. Cardiac‐related parasympathetic efferent postganglionic neurons are confined to intrinsic cardiac ganglia. The peripheral aspects of this hierarchy are, in turn, modulated by central neurons and circulating neurohumoral agents such as Ang II and catecholamines. Imbalances in cardiac neurohumoral control, especially those leading to excessive efferent neuronal activation, can lead to adverse short‐ or long‐term alterations in cardiac function. These involve structural and functional changes within the intrinsic cardiac nervous system, as well as cardiac arrhythmia induction and pump failure. We have proposed that stabilization of imbalances within select elements of the cardiac neuronal hierarchy can i) reduce the arrhythmogenic potential of cardiac tissues and ii) act to maintain myocyte viability in the presence of regional ischemia. Thus, the cardiac neuronal hierarchy has emerged as a novel therapeutic target for managing cardiac disease via pharmacological, physical or electrical means. HL71830