A Unifying Hypothesis of the Pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS),,,,,

It is very interesting. About 10 years ago I tried large doses of clenbuterol (I believe it is beta 2 agonist too but stronger than albuterol). And a miracle happened: After more than 10 years in a zombie state I was able to run and drive the bibycle. Unfortunately I wasn't able to replicate this since then. Large doses of clenbuterol are great burden to heart.
Did you experience heart problems or were you told that it was dangerous? Did you continue to take the medicine, but the response faded, or did you discontinue the medication as a precaution?