Pronunciation: (sis'tu-lē", -lē), [key]
1. Physiol.the normal rhythmical contraction of the heart, during which the blood in the chambers is forced onward. Cf. diastole.
2. Class. Pros.the shortening of a syllable regularly long.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.