Well, I wish I'd been as lucky as you guys and found out about the Bicuspid valve and aortic coarctation (narrowing, another of those genetic conditions that often occurs alongside a bicuspid valve) before they became a problem.
The alternative is to contract infective bacterial endocarditus (as mentioned above, mine was your good old streptococcus bacteria. Most people get a sore throat, I get two lots of open heart surgery!) which, due to a certain amount of medical incompetence from my family GP went undetected for nearly 2 1/2 months.
Result is an artificial replacement for the (completely destroyed, I saw the echocardiogram they did and there was almost as much flow back as forward through it) aortic valve, and also a replacement of a section of the downgoing aorta to repair the narrowing.
Cue Warfarin for life (apparently not a permissible drug for flying, although if it can be demonstrated as stable for 6 months then it's a possibility) and facing the possible loss of licence.
However, it's reassuring to see that the things I thought might have meant a complete end to my flying career, such as the valve replacement and the pacemaker, really aren't necessarily that. Just spoken to the lovely people at the CAA and they were extremely helpful. I'm still a bit wary about getting my hopes up of regaining my licence, but it seems there are people out there with similar experiences who are still flying!
Interesting to hear that it might leave me with a multi-crew only licence, I think after all that I've been through I'd be MORE than happy with that!