Did this test and the stress test with injections of isotopes. Also told was a better indicator of how the heart is working. That way the cardiologist can actually watch the blood flow on his screen during exercise to determine any obstruction.
I too was told a heart attch may be occuring, They had me wear a monitor for 24 hrs. After I REPEATEDLY told them how much I ride (3500 last year) they finally said all OK. I do have palputations. Was on Beta blockers (long thread seferal months ago) and was worried over high HR (I saw 208) when I got off. I've been off beta blockers for about 4 months now, but no bikes. When running/walking hard up a hill, I usually hit 170 (I'm 60).

3 Drs finally told me 'What heart trouble?" Keep cycling.