To identify myocardial infraction on an ECG, a therapist should look for which characteristic?

Identifying myocardial infarction (MI) on an ECG is critical for prompt diagnosis and treatment. The presence of a significant Q wave is a fundamental characteristic used to diagnose MI, particularly when assessing for a previous or ongoing infarction.

When myocardial tissue dies due to ischemia, it leads to cellular necrosis, which can result in the formation of pathological Q waves. These Q waves indicate a loss of the electrical activity in the region of the heart that has been affected by the infarction. Typically, a significant Q wave is at least one-third the height of the R wave in that lead or at least 0.04 seconds in duration. This change is significant enough to differentiate it from normal variations seen on the ECG.

While elevated ST segments and inverted T waves are also indicators of myocardial ischemia and can be seen during an acute MI, they can be transient and may not always persist after the acute phase. Normal sinus rhythm, on the other hand, suggests that there are no significant conduction disturbances or rhythm abnormalities present, but it does not provide information about the presence of ischemic events.

Thus, the characteristic of a significant Q wave is particularly indicative of myocardial damage and is used as a diagnostic criterion to help identify myocardial infarction on