After encountering an acute heart attack, patients should be monitored for cardiac enzymes after hospitalization. There are three main myocardial markers, and the changes in myocardial markers after an acute heart attack are as follows: 1. myoglobin: it starts to rise 2 hours after the onset, and can start to rise with myocardial necrosis. After rising for about 12 hours, it reaches a peak value and falls back for 24-48 hours; 2. Troponin: Troponin generally starts to rise for 3-4 hours, with a peak for 11-24 hours, and will return to normal values within a week; 3. Cardiac enzymes: 4-6 hours starts to show elevated cardiac enzymes, with a peak value for 16-24 hours, and the value usually falls back to normal range for about a week. Myocardial enzymes are also a marker to determine the recanalization of infarcted vessels, and a marker to reflect the size of myocardial infarction.