Why cardiac cycle is a cycle?

The cardiac cycle is the performance of the human heart from the ending of one heartbeat to the beginning of the next heartbeat.It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, dubbed systole.

Water flows along the east coast and across the western tropical pacific towards south america, while they both are directed towards that way,  el niño does not directly affect the southern flow of water along the coast.