cardiovascular system disease pathway myocardial infarction pathway Myocardial infarction, commonly known as heart attack, is a serious, sudden heart condition characterized by varying degrees of chest pain, weakness, sweating, nausea and vomiting, sometimes causing loss of consciousness. It occurs when parts of the heart muscle die because they are not supplied with enough blood. PW:0000299 heart attack pathway myocardial infarct pathway pathway