presystole

presystole

 [pre-sis´to-le]
the interval just before systole.

pre·sys·to·le

(prē-sis'tō-lē),
That part of diastole immediately preceding systole.
Synonym(s): late diastole

pre·sys·to·le

(prē-sis'tŏ-lē)
That part of diastole immediately preceding systole.