Myocardial Infarction: An Issue of Cardiology ClinicsAbout This Hardback A myocardial infarction (MI), usually known as a heart attack, happens when blood flow to a part of the heart reduces or discontinues, causing injury to the heart muscle. The most common symptom is chest pain or discomfort that may travel to the shoulder, arm, back, neck or jaw. It typically takes place in the middle or left hand side of the chest. A few of its other symptoms are shortness of breath, nausea, weakness, cold sweat,