What EKG sign is primarily used to indicate necrosis in myocardial infarction?

What EKG sign is primarily used to indicate necrosis in myocardial infarction?

• A. Flat T waves
• B. Significant Q waves
• C. Elevated ST segments
• D. Depressed ST segments

Answer: (B)

The presence of significant Q waves on an EKG is a critical indicator of necrosis in the context of myocardial infarction. When myocardial tissue undergoes necrosis, such as during a prolonged period of ischemia, it leads to a loss of functional myocardial cells. This is reflected on the EKG as the development of Q waves, which become more pronounced over time and typically indicate that there has been irreversible damage to the heart muscle.

Q waves signify a depolarization change due to the absence of normal myocardial activity in the affected area, resulting in a discrepancy in the electrical conduction pattern. As a result, these waves often appear deeper and wider than normal. They are particularly important in distinguishing between a recent myocardial infarction and a previous one, as significant Q waves can evolve days or weeks after the onset of the infarction.

In contrast, while flat T waves may suggest myocardial ischemia, they do not specifically indicate necrosis. Elevated ST segments can point to acute ischemia, and depressed ST segments typically suggest non-specific myocardial injury or ischemia but are not definitive for necrosis. Therefore, significant Q waves are the hallmark of myocardial necrosis on an EKG, making this the correct choice.