Myocarditis
Myocarditis is an inflammation of the heart muscles (myocardia). [7] Most people who have the condition show no serious symptoms, so it is hard to know the extent of its prevalence. It is mostly caused by a viral infection, but it may also be caused by bacterial and fungal infections. Certain drugs and allergic reactions to chemicals can also cause it.
Myocarditis is usually a temporary infection that resolves on its own, but it may also lead to left-sided congestive heart failure. Left-sided heart failure is due to the inability of your left ventricle to properly pump blood out of the lungs. This can cause fluid to build up in the lungs and impair breathing.