Neurocardiology: Structure‐Based Function

Abstract

Cardiac control is mediated via a series of reflex control networks involving somata in the (i) intrinsic cardiac ganglia (heart), (ii) intrathoracic extracardiac ganglia (stellate, middle cervical), (iii) superior cervical ganglia, (iv) spinal cord, (v) brainstem, and (vi) higher centers. Each of these processing centers contains afferent, efferent, and local circuit neurons, which interact locally and in an interdependent fashion with the other levels to coordinate regional cardiac electrical and mechanical indices on a beat-to-beat basis. This control system is optimized to respond to normal physiological stressors (standing, exercise, and temperature); however, it can be catastrophically disrupted by pathological events such as myocardial ischemia. In fact, it is now recognized that autonomic dysregulation is central to the evolution of heart failure and arrhythmias. Autonomic regulation therapy is an emerging modality in the management of acute and chronic cardiac pathologies. Neuromodulation-based approaches that target select nexus points of this hierarchy for cardiac control offer unique opportunities to positively affect therapeutic outcomes via improved efficacy of cardiovascular reflex control. As such, understanding the anatomical and physiological basis for such control is necessary to implement effectively novel neuromodulation therapies. © 2016 American Physiological Society. Compr Physiol 6:1635-1653, 2016.

Pathological effects of chronic myocardial infarction on peripheral neurons mediating cardiac neurotransmission

“…Autonomic neuronal dysfunction plays a crucial role in the genesis of cardiac arrhythmias and/or progression of the failing heart (Fukuda et al, 2015; Vaseghi et al, 2008). The cardiac neuronal hierarchy is primarily focused on dynamic coordination of cardiac function to match whole body metabolic demands (Armour et al, 2004a) and includes neural networks located from the level of the heart (Ardell, 1994; Armour, 1991) and intra-thoracic extra-cardiac ganglia to the insular cortex (Oppenheimer et al, 1994). …”

“…At the organ level, the intrinsic cardiac nervous system (ICNS) comprises a distributed network of ganglia and interconnecting nerves (Ardell, 1994; Armour, 1991). Neurons within cardiac GPs interact in concert with neurons in intra-thoracic extra-cardiac (sympathetic) ganglia, nodose and dorsal root ganglia (DRG), and higher center neurons (including spinal neurons).…”

Recurrent myocardial infarction: Mechanisms of free-floating adaptation and autonomic derangement in networked cardiac neural control

“…Specifically, it has been shown that the ICNS has the capability to exert bidirectional integrated reflex control of cardiac electrical and mechanical function, even when functioning disconnected from all higher neural elements of the cardiac nervous system ([9] and [10]). Furthermore, intrathoracic reflex control of the heart is partially maintained following decentralization of stellate ganglia bilaterally [11]. In other words, the ICNS and ITNS are capable of a degree of autonomous function with respect to central inputs.…”

“…Among these ganglia, common shared inputs (afferent and efferent), inter- and intra-ganglionic interconnections mediated by LCN’s sub-serve and assure beat-by-beat coordination of regional cardiac (electrical and mechanical) indices ([11] and [12]). Both the intrinsic and intrathoracic nervous systems receive central inputs and afferent inputs that represent a complex mix of information from the heart, lungs, carotid and aortic baroreceptors, viscera, periphery and a host of other factors.…”

Marshaling the Autonomic Nervous System for Treatment of Atrial Fibrillation

“…GPs are not simply “relay stations” for ANS projections to the heart; they contain sympathetic efferent, parasympathetic efferent, sensory afferent, and local circuit neurons (8,9). Extensive processing of these inputs occurs at the level of the ICN.…”