As a medical professional with expertise in cardiology, I can provide you with an overview of how a ST-segment elevation myocardial infarction (STEMI) is diagnosed. The diagnosis of STEMI is typically made using a combination of clinical presentation, 12-lead ECG, and cardiac enzymes. 1. Clinical Presentation: Patients with STEMI often present with symptoms such as chest pain, shortness of breath, nausea, and sweating. The pain is typically described as pressure, tightness, or discomfort and may radiate to the arms, neck, jaw, or back. 2. 12-lead ECG: The ECG is a crucial diagnostic tool in identifying STEMI. It provides a graphical representation of the heart's electrical activity. In a STEMI, there is characteristic ST segment elevation, which indicates that the coronary artery is completely blocked, and the heart muscle is not receiving sufficient oxygen. This ST segment elevation is localized to the ECG leads that correspond to the area of the heart muscle that is affected. The diagnostic criteria for STEMI on ECG typically require at least 1 mm of ST elevation in two contiguous leads. However, there are exceptions to this rule, such as in cases of left bundle branch block or when the patient has a paced rhythm, where the ECG may not show the typical changes. 3. Cardiac Enzymes: After the onset of symptoms, certain cardiac enzymes, such as creatine kinase (CK) and its MB isoenzyme (CK-MB), troponin T and I, begin to rise in the bloodstream. These biomarkers are released when heart muscle cells are damaged or die. Elevated levels of these enzymes, particularly troponin, are indicative of myocardial necrosis, which is a hallmark of STEMI. 4. Other Diagnostic Considerations: In addition to the ECG and cardiac enzymes, other diagnostic tests may be considered, such as echocardiography to assess left ventricular function and to rule out other causes of chest pain, or coronary angiography to visualize the coronary arteries and confirm the presence of a blockage. It's important to note that timely diagnosis is critical in STEMI because the sooner treatment is initiated, the better the chances are for limiting damage to the heart muscle and improving outcomes. read more >>

The diagnosis of STEMI is predominantly using the 12-lead ECG and cardiac enzymes. ... ST segment elevation, unlike depression, will localize to the ECG lead of the affected myocardium. Note that 1 mm of ST elevation in 2 contiguous leads is required to diagnose STEMI, however there are two major exceptions.read more >>