pulsation

(noun) (electronics) a sharp transient wave in the normal electrical state (or a series of such transients). Synonyms: pulsing, pulse, impulse. Examples: "The pulsations seemed to be coming from a star."

(noun) a periodically recurring phenomenon that alternately increases and decreases some quantity.

(noun) the rhythmic contraction and expansion of the arteries with each beat of the heart. Synonyms: pulse, heartbeat, beat. Examples: "He could feel the beat of her heart."