I posted this question on MTBR and RBR too. After a stress test and cardiac catherization, I've been diagnosed with a Myocardial Bridge and a 75% blockage and %30 blockage in 2 branch arteries. The blockages are going to be treated with meds, asperine routine and Zorcor, and watching my diet. The Bridge is another issue. My cardiologist recommended, if I want to keep cycling at a high level,(fast group rides and mtb races) that I have the bridge repaired, which would be surgury. A myocardial bridge is when some of the heart muscle is wrapped around, in my case, the main left artery. When the heart beats, it compresses the artery, then releases it. When the heart rate is high, the threat could be an arrhythmia, which can cause sudden cardiac death. I'm 49, been cycling (MTB and road) for 10 years and been racing, (MTB sport class, 24 hours, 100 miler's) for about 5 years. I never displayed any symptoms related to the bridge according to my doctors. My symptoms were a result of exercised induced asthma. My family doc was treating me for this and recommended, just in case, a stress test, and the stress test showed some eratic bloodflow, thus the cardiac catherization, which detected the bridge. I have an appointment with a surgeon in a few weeks to discuss my options. My doc recommended I stay off the mountain bike. I've been riding my road bike, and keeping my efforts easy to moderate, but this whole thing has me pretty freaked out. Apparently this condition occurs at birth, so I've always had it.
Anyone else have a similar story? I'm hoping this isn't the end of cycling for me. Its more than a hobby as you all know.
Thanks

I had a cardiac catherization done @ the age of 47, afterwards was told I had high blood pressure.
but I did keep riding and it was all very moderate for about six weeks, kept my heart rate @ 120 or below, seemd like I was not even peadling, but better than not riding at all.
I slowly increased my endurance and miles again, I am 54 now still use the meds. and no significant problems.

Follow the Drs. advice, as well as the cardiologist, there should be no problems with your continuance of cycling after the surgery, just go slow and steadly build up your miles and strength back up again.