You know what they say, when life gives you lemons....bring out the Tequila!
my dad has the same thing and we climbed Kilimanjaro in 1999 and he had his heart trip at 5400m above sea level on te descent. It left him panting on his knees for more than an hour in the thin air and killing sun. Not a pretty thing. He had the op and it never really helped fix the issue, but the it has not slowed him down. At 71 he still hikes regularly with no problems.