Reviewing the Symantec Messaging Gateway 10.5 logs, usually from the Control Center through Status > Logs, several entries are found that reference heartbeat_init. Previous versions of the Symantec Messaging Gateway did not display these log entries.
The entries look similar to these:
2013 Aug 21 18:06:16 PDT (err) ecelerity:  heartbeat_init -> Default
These warnings are related to the initialization of a process monitoring and handling function of the Symantec Messaging Gateway.
These initialization messages are normal processing and can be ignored. The level that they are logged at will be modified in future releases so they will not display under default logging levels.