Cardiac Innervation and Sudden Cardiac Death

Abstract

Afferent and efferent cardiac neurotransmission via the cardiac nerves intricately modulates nearly all physiological functions of the heart (chronotropy, dromotropy, lusitropy and inotropy). Afferent information from the heart is transmitted to higher levels of the nervous system for processing (intrinsic cardiac nervous system, extracardiac-intrathoracic ganglia, spinal cord, brain stem and higher centers) which ultimately results in efferent cardiomotor neural impulses (via the sympathetic and parasympathetic nerves). This system forms interacting feedback loops that provide physiological stability for maintaining normal rhythm and life-sustaining circulation. This system also ensures that there is fine-tuned regulation of sympathetic-parasympathetic balance in the heart under normal and stressed states in the short (beat to beat), intermediate (minutes-hours) and long term (days-years). This important neurovisceral /autonomic nervous system also plays a major role in the pathophysiology and progression of heart disease, including heart failure and arrhythmias leading to sudden cardiac death (SCD). Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extra-cardiac neural remodeling have also been identified and characterized during the progression of disease. Recent advances in understanding the cellular and molecular processes governing innervation and the functional control of the myocardium in health and disease provides a rational mechanistic basis for development of neuraxial therapies for preventing SCD and other arrhythmias. Advances in cellular, molecular, and bioengineering realms have underscored the emergence of this area as an important avenue of scientific inquiry and therapeutic intervention.

Influence of bisfenol A on chemical coding of the nerve fibers of the cardiac apex in the domestic pig

“…Ponadto wiadomo, że świnia domowa coraz częściej bywa używana jako model zwierzęcy fizjologicznych i patologicznych procesów zachodzących w organizmie ludzkim (23,32,40). Z kolei wybór koniuszków serca do niniejszych badań wynikał z budowy anatomicznej serca, ponieważ w tym właśnie jego fragmencie występują włókna mięśniowe wspólne dla obydwu komór, odpowiedzialne za wytwarzanie głównej siły skurczu serca, a ich unerwienie wydaje się kluczowe dla właściwej pracy tego narządu (13,38).…”

“…Powszechnie wiadomo bowiem, że włókna leżące w mięśniu sercowym mogą być wypustkami neuronów zlokalizowanych poza tym narządem (unerwienie zewnątrzpochodne współczulne i przywspół-czulne) lub komórek położonych na terenie zwojów śródsercowych (13,30).…”

A Time-Varying Nonparametric Methodology for Assessing Changes in QT Variability Unrelated to Heart Rate Variability

“…In a recent study, muscle sympathetic nerve activity measured in the peroneal nerve, one of the few established direct measures of sympathetic activity, did not contribute significantly to QTV during rest or head-up tilt at 40 degrees [22]. Own to its prominent role in sudden cardiac death [46], [54], the interaction between sympathetic modulation and repolarization dynamics deserves further investigation.…”

The Future of Arrhythmias and Electrophysiology

“…Therapies to modulate autonomic outflow to the heart, such as stimulation of the spinal cord, carotid body, and vagus nerve, and targeted ablation of autonomic fibers, such as the perivascular renal nerves, stellate ganglia and upper thoracic sympathetic ganglia, and cardiac ganglia are already available or in trials, but our understanding of the physiology involved is limited. 37 Refined methods for autonomic modulation have promise to reduce arrhythmias and also to favorably influence the underlying structural heart disease. As these therapies are refined, more targeted approaches will be developed.…”