The heartbeat monitoring agent is designed to be installed only on a small number of hosts, usually one.
It is not necessary and recommended to install the heartbeat agent on multiple computers. The heartbeat monitoring agent will ping and monitor all configured computers from one central location.
If you have a large number of computers to monitor (e.g. 1000) then you can install the heartbeat monitoring agent on more than one computer.
A KB on how to install Heartbeat on a remote computer is available here KB-479