ECG changes are crucial for diagnosing myocardial infarction (MI). In the case of Non-ST-elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP), the differentiation is usually retrospective, based on the presence or absence of raised cardiac enzymes at 8-12 hours after the onset of chest pain [1].
In MI, ECG changes can vary based on the duration, size, and location of the infarction. For instance, in an anterior MI, ECG changes may include increased R wave amplitude and duration, a R/S ratio in V1 or V2 > 1, and hyperacute ST-T wave changes [3]. Hyperacute T waves, which become more prominent, symmetrical, and pointed, are often evident in the anterior chest leads [4].
The diagnosis of MI is not solely based on ECG; it also requires the detection of elevated serum cardiac enzymes [5]. A right ventricular infarct can be detected with a right-sided ECG, and it's advisable to do so in all inferior STEMI cases as RV involvement can change the management [7].
In the case of a large anterior MI, the ECG findings will be different; when an anterior MI extends to the septal and lateral regions, the culprit lesion is usually more proximal in the LAD or even in the left main coronary artery [8].
However, the context does not provide sufficient information about the specific ECG changes in various types of MIs.