The Collaborative International Dictionary
Perisystole
Perisystole \Per`i*sys"to*le\, n. [Pref. peri- + systole: cf. F. p['e]risystole.] (Physiol.) The interval between the diastole and systole of the heart. It is perceptible only in the dying.
Wiktionary
perisystole
n. (context physiology English) The interval between the diastole and systole of the heart.