Acute Pericarditis: This condition is characterized by inflammation of the pericardium, which can cause ST elevation on an electrocardiogram (ECG) due to the spread of the inflammatory process to the epicardium. The ST elevation is typically concave upwards and seen in multiple leads, including V2-V5. Negative troponins help differentiate it from acute myocardial infarction (AMI), as troponin levels are usually not significantly elevated in pericarditis.

Early Repolarization: A benign condition that can mimic ST elevation myocardial infarction (STEMI) on ECG. It is characterized by an upward displacement of the QRS-ST junction (J-point) with a slight ST elevation in the leads V2-V5, often accompanied by a notched J-point. Troponin levels are typically negative, and the clinical context (e.g., young, healthy individual without chest pain) supports this diagnosis.
Myopericarditis: A condition that involves both the myocardium and the pericardium, leading to symptoms and ECG findings that can overlap with both myocarditis and pericarditis. The presence of ST elevation with negative troponins could suggest myopericarditis, especially if there are symptoms of both conditions.

Acute Coronary Syndrome (ACS) with Negative Troponins: Although less common, it's crucial not to miss ACS, especially if the patient presents early in the course of the disease or has a condition that might lead to false-negative troponin results (e.g., intermittent coronary occlusion). Clinical judgment and further diagnostic testing (e.g., serial troponins, echocardiography, coronary angiography) are essential.
Pulmonary Embolism (PE): While PE typically presents with different ECG findings (e.g., sinus tachycardia, right bundle branch block, S1Q3T3 pattern), it can occasionally cause ST elevation in the anterior leads due to right ventricular strain. Negative troponins do not rule out PE, especially in the context of hypoxia, tachycardia, and clinical suspicion of PE.

Hypokalemic or Hyperkalemic Cardiomyopathy: Severe electrolyte imbalances can lead to ECG changes, including ST elevation. While these conditions are less common causes of ST elevation in V2-V5, they are important to consider, especially in patients with known electrolyte disturbances or those on medications that can cause such imbalances.
Takotsubo Cardiomyopathy: Also known as stress cardiomyopathy, this condition can mimic STEMI with ST elevation on ECG but typically has a distinctive "balloon-like" left ventricular dysfunction on echocardiography. Troponin levels may be mildly elevated but are often not significantly increased. The clinical context (e.g., recent intense emotional or physical stress) and echocardiographic findings are key to this diagnosis.