The heart is supplied and controlled by centrally derived sympathetic and parasympathetic nerves. The classical augmenting influence of sympathetic inputs is accepted as dogma, but the inhibitory influence of the cervical vagus, in particular on ventricular function and electrophysiology is still passionately debated. Traditionally, autonomic control of the heart has focused on centrally derived extrinsic signals or the investigation of electrical stimulation of peripheral nerves. However, neurocardiac control is more complex owing to the existence of an extensive network of intrinsic cardiac neurons i.e. the intrinsic cardiac nervous system (ICNS) that has been collectively called the hearts ‘little brain’ (Randall et al., 1996; Ardell, 2004). These neurons can be characterised broadly speaking by 1) their anatomical / topographical layout, 2) their chemical phenotype and 3) their functional influences on the heart. This review will characterise the ICNS in each of these components.
Updated on March 17, 2020