1570s, from medical Latin diastole, from Greek diastole "drawing asunder, dilation," from diastellein, from dia- "through, thoroughly, entirely" (see dia-) + stellein "to set in order, arrange, array, equip, make ready," from PIE *stel-yo-, suffixed form of root *stel- "to put, stand," with derivatives referring to a standing object or place (see stall (n.1)).
diastole di·as·to·le (dī-ās'tə-lē)
The normal rhythmically occurring relaxation and dilatation of the heart chambers, especially the ventricles, during which they fill with blood.
The period during the normal beating of the heart in which the chambers of the heart dilate and fill with blood. Diastole of the atria occurs before diastole of the ventricles. Compare systole.
diastolic adjective (dī'ə-stŏl'ĭk)