I would expect these kinds of systems to be running a soft realtime OS. Or at the very least a run of the mill OS with no extraneous software running in the background.
Some great quotes:
"Mikko Hypponen, chief research officer for Finland-based F-Secure, said that infections of critical infrastructure were surprisingly common"
"Hypponen said he had recently spoken to a European aircraft maker that said it cleans the cockpits of its planes every week of malware designed for Android phones. The malware spread to the planes only because factory employees were charging their phones with the USB port in the cockpit."
The moral of the story: If you include any kind of port in something, people WILL plug things into it sooner or later.
Aeronautical and Automotive are both engineering driven, Medical isn't, it's a big grey area.
This application (cath lab activity logging) is not a life-support activity. Product failures of any kind (either due to design error or product defect) represent a diminished capability of diagnosis and treatment. This does not represent a risk of harm to a patient.
That said, some medical device manufacturers treat this aspect of design very seriously and go to great pains to use defeatured and heavily restricted OS and settings.