Gawain
Tried the BioTek Lionheart 3? You can imitate all sorts of intriguing heart defects with a huge menu and check out those new analyser-type ECG carts.
The supplier (as far as I know) is Ultramedic. With a few extra cables, you can also check out BP measurements, and there are bound to be more functions I haven't had chance to explore.
We have a few, and I don't recall anyone having any problems with them.