Monitoring last connection to SEPM on clientside.

I"m wondering if there is a registry value that stores the last successful connection time with SEPM on the client.  In sep when you open troubleshooting, and connection status, that info must be stored somewhere.   was wondering if anyone knew where.

Thought it was HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection\SMC\SYLINK\SyLink\heartbeatcomplete , but that doesn't match up.   Might be from install time, I dont know.

Basically I want to use a monitoring script so I can find online machines that haven't checked in.