If not going to America, suggest use up any EHIC and then get a GHIC card.
Only you can assess whether your condition is going to affect your holiday. Are you prone to falling about, dizziness, are you fit for your age? Also, are you going with someone younger?
Also, GPs are recommended to give statins to everybody these days, bear that in mind. Are you taking any dietary measures to keep LDL down and increase HDL? Omega-3s are good for that, also plant sterols and red rice. They keep mine down before I go and get my annual blood test. Look into it, lots of reasonable info online.