MasterDBRefreshInterval & infa.masterUpdateTimeInterval are two heartbeat properties related to internal health check of the Informatica nodes & domain. They can be configured to increase resiliency to intermittent communication glitches between the nodes and the domain database. This video describes how to configure the heartbeat properties.
How to automate the repository and domain back up process for disaster recovery in PowerCenter
How to find in which host the Repository Integration service is running in a multi node domain
Converting and adding of a self signed certificate to use a Webservice Consumer transformation