Interactions between the autonomic nervous system and tachycardias in man.

We have endeavoured to present an integrated and dynamic overview of the interaction between the autonomic nervous system and cardiac arrhythmias. Our purpose was not to be comprehensive, detailed, or all inclusive but to present a clinically relevant summary of some of the areas where autonomic tone may be pertinent. Clearly, most arrhythmias are not the result of a primary autonomic nervous system disorder. However, subtle and overt alterations in autonomic tone, interacting with rate, pressure, cardiac volume, contractility, and the intrinsic myocardial electrophysiologic properties likely exert a critical influence on many cardiac arrhythmias. We wish to emphasize that autonomic effects may be temporarily concealed or overwhelmed during certain states or by the administration of drugs. However, the modulating role of neural tone and neurotransmitters is almost always present, contributing significantly to the outcome of therapy.