OK, two points here.
- Once a client agent is deleted from the console, heartbeat discovery is the only way to "reanimate" the resource for the system. Other discovery methods will create a new resource that is not linked to the existing device.
- The log file you've called out and the process corresponding to it have nothing to do with heartbeat discovery.
If you want to increase the heartbeat discovery rate, then decrease its interval in your site's configuration. By default, this is every 7 days but I generally recommend setting this to at least every day (but no more than every 4 hours).