A 50-year-old man presents to the emergency department with acute chest pain, breathlessness, and palpitations. ECG shows ST-segment elevation in the anterior chest leads. Which of the following investigations is the most appropriate for confirming the diagnosis of acute myocardial infarction?

A.	Cardiac marker troponin T/I
B.	Echocardiography
C.	TMT
D.	24-hour Holter monitoring

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Correct Answer » A Explanation

Cardiac troponin I and troponin T are the most sensitive and specific biomarkers for myocardial injury and are the preferred laboratory tests for confirming acute myocardial infarction (AMI).

In a patient with symptoms suggestive of AMI and ST-segment elevation on ECG, troponin:

• Confirms myocardial necrosis.
• Helps establish the diagnosis.
• Has excellent sensitivity and specificity.

Although treatment of STEMI should not be delayed while awaiting troponin results, troponin remains the laboratory investigation of choice for confirming myocardial infarction.

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Why Other Options Are Incorrect

B. Transthoracic Echocardiography

• Incorrect because echocardiography is not the primary investigation to confirm acute myocardial infarction.
• It is used to assess:
  • Left ventricular function.
  • Regional wall motion abnormalities.
  • Mechanical complications (e.g., acute mitral regurgitation, ventricular septal rupture, free wall rupture).

C. Treadmill Test (TMT)

• Incorrect because TMT is contraindicated during acute myocardial infarction.
• It is performed later in patients with stable ischemic heart disease.

D. 24-hour Holter Monitoring

• Incorrect because Holter monitoring is used to evaluate intermittent arrhythmias.
• It has no role in confirming acute myocardial infarction.