(n): a main organ that is situated inside the body
(n): a small portable timepiece
(n): a measuring instrument or device for keeping time
(n): a character printer that automatically prints stock quotations on ticker tape
(n): a printer that prints a single character at a time
Actually, in a metaphoric sense, ticker can be a very poetic way to describe the heart. The idea that the heart is the internal time piece of the body, slowly ticking, winding down every down, until it runs out of beats and the clock stops.
I hate it in reference to people's hearts. tickertape is ok.