Patient Presentation and Key Findings

A 34-year-old patient experienced severe retrosternal chest pain. The initial Electrocardiogram (ECG) showed significant ST elevation ($\ge 3$ mm) in the anterior chest leads. Crucially, blood tests for cardiac biomarkers (CPK-MB, Troponin-T, AST) were normal. A follow-up ECG after 24 hours returned to normal.

Differential Diagnosis Analysis

• Acute Myocardial Infarction (MI): Characterized by chest pain, ST elevation, and elevated cardiac enzymes due to heart muscle damage. The normal enzyme levels in this patient make acute MI unlikely.
• Acute Pericarditis: Inflammation of the pericardium. While it causes chest pain and can show ST elevation, it's typically diffuse, often accompanied by PR depression, and less likely to present with localized anterior ST elevation and completely normal enzymes with rapid resolution.
• Prinzmetal's Angina (Variant Angina): Caused by temporary constriction (spasm) of coronary arteries. This can result in severe chest pain and transient ECG changes, including ST elevation, mimicking a heart attack. Importantly, cardiac enzymes remain normal as there is no permanent heart muscle damage. The ECG changes typically resolve quickly.

Conclusion

The combination of acute chest pain, significant ST elevation ($\ge 3$ mm) in specific ECG leads, normal cardiac enzymes, and rapid resolution of ECG changes strongly suggests coronary artery spasm rather than infarction or pericarditis. Therefore, Prinzmetal's angina is the most likely diagnosis.