Differential Diagnosis for ST Segment Elevation in Leads V1, V5, and V6

Single Most Likely Diagnosis

• Acute Anterior Myocardial Infarction (MI): ST segment elevation in leads V1, V5, and V6 is highly suggestive of an acute anterior MI, which involves the anterior wall of the heart. This pattern is indicative of occlusion in the left anterior descending (LAD) coronary artery.

Other Likely Diagnoses

• Acute Lateral Myocardial Infarction: While less common than anterior MI, ST elevation in leads V5 and V6 can also indicate a lateral MI, especially if there is accompanying ST elevation in leads I and aVL.
• Pericarditis: This condition can cause ST segment elevation in multiple leads, including V1, V5, and V6, due to inflammation of the pericardium. However, the ST elevation in pericarditis is typically more widespread and not limited to the anterior and lateral leads.
• Early Repolarization: A benign condition that can mimic ST elevation on an ECG, particularly in leads V5 and V6. However, the context and other ECG features can help differentiate it from acute MI.

Do Not Miss Diagnoses

• Pulmonary Embolism (PE): While not directly causing ST elevation in V1, V5, and V6, a large PE can lead to strain on the right ventricle, potentially causing ST elevation in leads V1-V4. Missing a PE can be fatal, so it's crucial to consider it in the differential, especially with symptoms like sudden onset dyspnea or chest pain.
• Aortic Dissection: This is a life-threatening condition that can sometimes present with chest pain and ST elevation on an ECG, although the ECG findings are not specific. A high index of suspicion is required, especially in patients with risk factors for aortic disease.

Rare Diagnoses

• Hypertrophic Cardiomyopathy: Certain forms of hypertrophic cardiomyopathy can lead to abnormal ECG findings, including ST segment elevation. However, this would be an unusual cause of acute ST elevation in leads V1, V5, and V6.
• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): A rare condition that affects the right ventricle and can cause abnormal ECG findings, including ST elevation in the right precordial leads. However, it's less likely to cause ST elevation in leads V5 and V6.
• Myopericarditis: An inflammatory condition that affects both the myocardium and pericardium, which can cause ST elevation on an ECG. The clinical context and additional diagnostic tests can help differentiate it from other causes of ST elevation.