how to check if a calendar event has been deleted

Good day to all,
I’ve a room that has to be heated only in specific moment.
I’ve set up an automation that start the heating a few hours before an event, in a common calendar, that include a specific word (and stop it at the end of the event).
In this way any user, can put an event in the calendar and have the room heated at the proper time.

This works quite fine, my only concern is if an event is canceled after the heating has been triggered (the few hours gap before the event start to let the room be heated).

In this case the heating will be on untill it is manually switched off,or I can set a default schedule that switch it off at a certain time (maybe during the night).

I’ve seen the possible calendar trigger are ‘start’ and ‘end’, there is a way to catch a canceled event and act on it?

Thanks