Choice E shows a typical, “tombstoning” appearance of ST elevation during an anterior myocardial infarction.
Choice A shows an ECG of an left ventricular aneurysm. Note the large Q waves (indicated old infarction) and the characteristic shape of the ST segments in the anterior precordial leads. The only true way to know that a left ventricular aneurysm is present would be to the patient’s history of a prior anterior myocardial infarction. Certainly this ECG in a patient presenting with chest pain would still be worrisome for anterior MI, but technically does not meet criteria which requires 2 mm of ST elevation in V2 and V3 in men > 40 years old according to the ACC/AHA definition. A total of 2.5 mm is required in men < 40 years old and only 1.5 mm required in women.
Choice B is consistent with pericarditis. Inflammation of the pericardium can result in pericarditis and has typical ECG findings that can mimic STEMI. These findings occur in progressive stages, all of which are seen in about 50% of cases of pericarditis. Stage I can mimic STEMI and consists of diffuse concave upward ST segment elevation in most leads, PR depression in most leads (may be subtle), and sometimes notching at the end of the QRS complex.
Choice C is consistent with left ventricular hypertrophy with a strain pattern. When LVH is present, the voltage on the 12-lead ECG is frequently increased (see LVH ECG review), however ST changes can occur with LVH as well mimicking STEMI or ischemic ST depressions. This is referred to as "LVH with strain" or "LVH with repolarization abnormality". Distinguishing these changes from those during a STEMI is important, though often difficult. The typical pattern with LVH includes deviation of the ST segment in the opposite direction of the QRS complex (discordance) and a typical T wave inversion pattern is present.
Choice D is early repolarization. Early repolarization is a common finding in young, healthy individuals. It appears as mild ST segment elevation that can be diffuse, however is more prominent in the precordial leads. Early repolarization changes frequently look simply like “J point” elevation.