sys·to·le 
(sĭstə-lē)
(sĭstə-lē)n.
The rhythmic contraction of the heart, especially of the ventricles, by which blood is driven through the aorta and pulmonary artery after each dilation or diastole.
[Greek sustolē, contraction, from sustellein, to contract; see SYSTALTIC.]
sys·tolic (sĭ-stŏlĭk) adj.