joeseptuk,

The first thing I would do it ensure your doctor is happy for you to fly. If everything is fine with your doctor, I would take their advice and he/she may give you a letter (fitness to fly) in case there are problems. If the airline suspect any problems, they may ask you to see a doctor to prove fitness to fly so you can go prepared. Your doctor is the best person to advise if you need to tell anyone.

Darren

After my partners heart attack a few years back we were advised by the consultant to get a 'Fit to Fly' letter from our GP but were still told they they could refuse to board him if they were at all worried at the time of departure.
We elected not to tell the airline so as not to draw attention to the situation but made sure we arrived at the airport in plenty of time to be calm and rested before checking in.

I can speak from personal experience here. Airports are a place of expectation, excitement and paradoxically stress. The herd instinct comes to the fore. Just look at the people queing to check in for certain airlines, you would not expect their behaviour even in a prison at feeding time. Furthermore, the ground staff of certain airlines are not much better.

Therefore, somebody with a heart condition would be best advised to turn up at the airport early and go through the motions before the arrival of the largely impatient travelling masses.

Certain airlines (don't worry, I am not going to name them) and their staff are not good for people with problem heart conditions. You don't have to have a degree in Aviation Science to know which airlines I am talking about. It might prove prudent to book with a friendly airline (if possible). It may cost a few bob more, but in the long run you have a reserved seat and can access the plane in a civilised environment. And not only that, you arrive at your destination refreshed.

By the way, thanks to all genuinely friendly airline staff for their efforts.