Is there a plugin/script for nagios that monitors pitr being up to djavascript:;ate?

Is the a plugin or script that will allow pitr to be monitored and trigger an alarm when the pitr master/slave databases
get out of sync?

The reason I'm asking, I have had one or four of pitr'd slaves get out of sync twice?
Not sure why, it may have something to do with rsync on (wal log txfr), but not the point.

Any help would be appreciated...

Chris Barnes