The word "心肌梗塞" is formed by combining four characters: "心" meaning heart, "肌" meaning muscle, together forming "心肌" which refers to the heart muscle; "梗" meaning obstruction or blockage, and "塞" meaning to plug or block, together forming "梗塞" which denotes an infarction or blockage. Thus, the entire compound directly describes a blockage in the heart muscle, i.e., a myocardial infarction.