As a medical professional with expertise in cardiology, I can tell you that a ST-elevation myocardial infarction (STEMI) on an EKG typically presents with specific characteristics that are crucial for timely diagnosis and treatment. On an EKG, a STEMI is often characterized by the following: 1. ST-segment elevation: This is a key feature and refers to an elevation of the ST segment above the baseline by at least 1 mm in two or more contiguous leads. The ST segment represents the period between the end of the QRS complex (which signifies the ventricles depolarizing) and the beginning of the T wave (which signifies the ventricles repolarizing). 2. Q waves: In some cases, there may be Q waves present, but these are not as pronounced as in a non-STEMI (NSTEMI). Q waves in a STEMI are often due to the infarcted tissue, but they are typically smaller and less deep than those seen in NSTEMI. 3. T wave inversion: This is not a primary feature of STEMI but can be seen in the leads opposite to the infarct, indicating ischemia. 4. Symptoms: While not visible on the EKG itself, it's important to note that patients with STEMI often present with symptoms such as chest pain, shortness of breath, nausea, and sweating, which should be taken into account when interpreting the EKG. It's important to remember that the diagnosis of a STEMI is not based solely on EKG findings but also on the clinical presentation and other diagnostic tests. read more >>

These are the septal and anterior ECG leads. The MI is posterior (opposite to these leads anatomically), so there is ST depression instead of elevation. Turn the ECG upside down, and it would look like a STEMI. ... ST segment elevation in the posterior leads of a posterior ECG (leads V7-V9).read more >>