I would look into a little know athletes disease called ARVD (arrythmogenic right ventricular dysplasia), it is a genetic disease that can cause rhythm problems. I don't know about what having an athletes heart means. But if your EF is lower than normal then there is usually something wrong with the heart. It does not matter what your husband can do, rhythm problems can strike at any time. Has he had CT scans, MRIs done. The MRI is the best for seeing stuff. I cannot have them, I have a defibrillator implanted. Maybe you should seek a second opinion, see a EP cardio doc.
Good luck!
Jill
my son also was diagnosed with HCM which I don't believe he has. I think he has athletes heart but all the docs seem to be sticking together after reviewing all the same records. His interventricular septum measured at 1.5 which is high but he has always been very active, lifting weights and playing football. We need to see someone who knows that they are doing and can make an opinion on their own w/o looking at other drs. records. Any suggestions?