tailieunhanh - Cardiology Core Curriculum A problem-based approach - part 4

Thời gian phát hành đánh dấu huyết thanh trong nhồi máu cơ tim cấp tính. (Xem văn bản cho biết thêm chi tiết) CK, creatinin kinase; LDH, lactate dehydrogenase. Thích nghi với sự cho phép từ Antman6 | Cardiology Core Curriculum Figure Electrocardiographic changes characteristic of pericarditis. Concave upsloping ST elevation is seen diffusely together with PR-segment depression. Importantly T waves are essentially normal which is another distinguishing feature from ST-segment elevation myocardial infarction Figure Time course of serum marker release in acute myocardial infarction. See text for details. CK creatinine kinase LDH lactate dehydrogenase. Adapted with permission from Antman6 approximately 18 hours and return to normal in approximately 3 days Figure .6 Cardiac troponins T cTnT and I cTnI are contractile proteins that are released in response to myocardial necrosis. Like CK and CK-MB these enzymes are detectable 3-6 hours after the onset of chest pain 180 Acute coronary syndromes and peak at approximately 14-20 hours see Figure . They differ however in that they remain elevated for up to 14 days after infarction. This prolonged detection window facilitates the diagnosis of remote infarction . an infarct that occurred in the days or weeks before presentation but makes the diagnosis of early recurrent infarction difficult. Because cTnT and cTnI are not found in adult skeletal muscle they are highly specific for myocardial injury and thus are excellent markers for confirming the diagnosis of MI. The normal reference range for the cardiac troponins is set at a very low level as a result troponins are very sensitive for the detection of small amounts of myocardial necrosis. Indeed it has recently been shown that patients with minor myocardial necrosis as evidenced by low level troponin elevation in the absence of CK and CK-MB elevation are at increased risk for the development of adverse clinical This finding has led to a revised more liberal definition of myocardial infarction that now includes patients with low level troponin elevation even if CK and CK-MB are normal. Myoglobin is a small cytosolic molecule that is rapidly .