A 36-year-old male comes with a 2-day history of chest pain. The pain has been continuous and does not change with activity. Vital signs show normal BP, mild tachycardia and tachypnea, and an oxygen saturation of 90% on room air. Cardiopulmonary exam is normal. An ECG shows a rate of 106 beats/min, left axis detion, left ventricular hyperophy, PR depression, and T wave inversions in V2 to V5. Troponin and CPK-MB are minimally elevated. What is the most likely diagnosis.

## **Core Concept**
The patient's presentation suggests an acute coronary syndrome (ACS), but the minimally elevated troponin and CPK-MB levels along with specific ECG findings point towards a condition that mimics ACS but is not primarily caused by atherosclerotic plaque rupture or coronary thrombosis.

## **Why the Correct Answer is Right**
The clinical presentation and ECG findings are highly suggestive of **acute pericarditis**. Key features supporting this diagnosis include:
- Chest pain that is continuous and does not change with activity, which is typical for pericarditic pain.
- ECG findings of PR depression (a hallmark of pericarditis), T wave inversions in multiple leads (V2 to V5), and a normal or slightly elevated heart rate.
- The presence of left ventricular hypertrophy could be a pre-existing condition or secondary to another process but does not rule out pericarditis.
- Minimally elevated troponin and CPK-MB levels are consistent with pericarditis, as there can be some myocardial involvement (myopericarditis).

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, ACS (like myocardial infarction) would show more significant elevations in troponin and CPK-MB.
- **Option B:** This option is not provided, but myocarditis could present similarly; however, the specific ECG pattern and clinical context here more strongly suggest pericarditis.
- **Option D:** This option is not provided, but conditions like pulmonary embolism or acute aortic syndromes would have different ECG findings and clinical features (e.g., sudden onset dyspnea, hypotension).

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **acute pericarditis** often presents with chest pain that improves with leaning forward and worsens with lying down or breathing deeply, which was not mentioned but is a classic symptom. The ECG pattern of PR depression is particularly suggestive of pericarditis.

## **Correct Answer: C. Acute Pericarditis.**

✓ Correct Answer: C. Pericarditis