The term "myocardial" refers to anything related to or involving the heart muscle. Specifically, it is used to describe damage or disease affecting the myocardium, which is the thick layer of specialized cardiac muscle tissue that makes up the bulk of the heart. This can include conditions such as a heart attack (myocardial infarction), where blood flow to part of the myocardium is interrupted and causes damage or death to the affected heart muscle cells, leading to chest pain, shortness of breath, and other symptoms.