Imaging sympathetic innervation

The autonomic innervation of the heart modifies most cardiac functions, Esp ecially the heart rate and the force of contraction of myocytes are modulat ed by the autonomic nervous system. A number of specific neurotransmitters interact with receptors on post- and presynaptic binding sites regulating t he complex electromechanical system of the heart. Disturbances at this inte raction result in a variety of cardioneuropathies. The clinical manifestati ons can be mild and may only consist of sporadic arrhythmias without hemody namic effects. In some cases however the autonomic dysfunction may be sever e, e.g. in the acute phase of the Guillain-Barre syndrome and in advanced d iabetic neuropathy. At present, the only available techniques to visualise and quantitate disbalanced innervation of the myocardium are scintigraphic modalities as single photon emission tomography (SPECT) and positron emissi on tomography (PET) with appropriate radiopharmaceuticals. These methods ar e reviewed with respect to their possible clinical application and to futur e developments.