Can myocarditis be cured by diet alone?

No: Medication is almost always needed at least for a while. Many cases improve or resolve over time regardless. Mild cases may be detected incidentally, without any apparent cardiac complaints.

Maybe: Consider high dose coq 10 supplements. Also consider d ribose. Heart muscle needs tremendous energy to keep pumping well. Coq is critical for making energy. Also consider eating coconut oil as the medium chain fats in it are easily burned for energy.