It appears that a childhood friend recently had a brush with some cardiac-related problems, and is currently at home and on the mend.
Ray, at the age of 24, I had a similar event occur, although it was limited to my heart's nervous pathways. A gazillion tests were conducted; at Lankenau in 1980, and many years later at Strong Memorial Hospital in Rochester NY when a specialist in heart arrhythmia took personal interest in my case and ran another battery of tests as part of a research project. Both times, the cause of my "problem" - a/k/a complete heart block - was never pinpointed.
In October 1981, eighteen months after my life changed forever, I won the Eastern U.S. Powerlifting Championship in the 100 kg. weight class...and I've never looked back.
I know where you are because I've been there. My simple advice: take care of yourself, listen to the advice being given by the medical professionals responsible for your rehab, and as each new day begins - step by step...
keep moving forward.