Bathmotropic

Bathmotropic (derived from the Greek word "bathmos", meaning step or threshold) refers to modification of the degree of excitability (threshold of excitation), of musculature in general, and of heart musculature specifically. It is used especially to describe the effects of the cardiac nerves on cardiac excitability. Positive bathmotropic effects increase the response of muscle to stimulation, whereas negative bathmotropic effects decrease the response of muscle to stimulation. Bathmotropic is one of five adjectives used to describe various qualities of the cardiac cycle; the other four are: inotropic, chronotropic, dromotropic and lusitropic. In an article in the American Journal of Medical Sciences, these five terms were described as the five fundamental properties of the heart. While bathmotropic, as used herein, has been defined as pertaining to modification of the excitability of the heart, it can equally well refer to modification of the irritability of heart muscle, and the two terms are frequently used interchangeably.