In MI diagnosis, which ECG finding may support the diagnosis besides troponin elevation?

In MI diagnosis, which ECG finding may support the diagnosis besides troponin elevation?

• A. Normal ECG
• B. New pathological Q waves on ECG
• C. ST-segment elevation only present in leads not contiguous
• D. T wave flattening only

Answer: (B)

New pathological Q waves on the ECG are the best finding to support an MI diagnosis alongside troponin elevation because they signify necrosis of the heart muscle in a specific region. When myocardial tissue undergoes full-thickness (transmural) infarction, the electrical forces in that area change, creating Q waves that are new compared with the patient’s prior tracing. The presence of these new Q waves in contiguous leads points to a particular coronary territory being affected and confirms that infarction has occurred, even as troponin confirms myocardial injury. Other possibilities don’t fit as well. A normal ECG would not align with myocardial injury, since MI typically produces some ECG changes. ST-segment elevation confined to non-contiguous leads is atypical for a single infarct and doesn’t map clearly to a coronary territory. T wave flattening alone is nonspecific and can occur with many non-ischemic conditions as well as during evolving ischemia.

New pathological Q waves on the ECG are the best finding to support an MI diagnosis alongside troponin elevation because they signify necrosis of the heart muscle in a specific region. When myocardial tissue undergoes full-thickness (transmural) infarction, the electrical forces in that area change, creating Q waves that are new compared with the patient’s prior tracing. The presence of these new Q waves in contiguous leads points to a particular coronary territory being affected and confirms that infarction has occurred, even as troponin confirms myocardial injury.

Other possibilities don’t fit as well. A normal ECG would not align with myocardial injury, since MI typically produces some ECG changes. ST-segment elevation confined to non-contiguous leads is atypical for a single infarct and doesn’t map clearly to a coronary territory. T wave flattening alone is nonspecific and can occur with many non-ischemic conditions as well as during evolving ischemia.