Acute Myocardial Infarction: Differential Diagnosis Methods

Acute myocardial infarction (AMI) typically presents with sudden and intense chest pain. However, this symptom can overlap with several other serious conditions, making accurate diagnosis essential. It is crucial to distinguish AMI from diseases such as pulmonary embolism, pericardial effusion, acute pericarditis, and aortic dissection, all of which can cause acute chest pain.

Key Characteristics of Acute Myocardial Infarction

The chest pain associated with AMI is often described as severe and persistent, accompanied by a sense of impending doom, diaphoresis (excessive sweating), and sometimes nausea or fatigue. Electrocardiogram (ECG) findings are critical in diagnosing AMI, as they typically show a progressive evolution consistent with myocardial injury. These changes may include ST-segment elevation, T-wave inversion, and the development of pathological Q waves.

Differentiating Acute Pericarditis

Acute pericarditis often presents with sharp, pleuritic chest pain that may improve when sitting up or leaning forward. Patients may also report a recent history of viral illness or other signs of infection. Diagnosis can be supported by echocardiography, which may reveal pericardial effusion. While pericarditis can mimic AMI, the presence of diffuse ST-segment elevation on ECG (without reciprocal changes) and normal cardiac biomarkers can help distinguish it from myocardial infarction.

Identifying Pulmonary Embolism

Pulmonary embolism (PE) is another critical condition that must be ruled out in patients presenting with acute chest pain. Symptoms often include pleuritic chest pain, dyspnea (shortness of breath), tachypnea (rapid breathing), and hemoptysis (coughing up blood). Blood gas analysis may reveal hypoxemia (low oxygen levels), and ECG changes may show signs of right heart strain, such as S1Q3T3 pattern. Echocardiography can also demonstrate right ventricular dilation and increased pulmonary artery pressure. Confirmatory diagnosis is usually made with a CT pulmonary angiogram.

Recognizing Aortic Dissection

Aortic dissection is a life-threatening condition characterized by a sudden, tearing, or ripping type of chest pain that is often more severe at onset than in other causes of acute chest pain. The pain may radiate to the back or abdomen and can rapidly lead to hemodynamic instability. Unlike AMI, the diagnosis of aortic dissection relies heavily on imaging studies such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA) to visualize the dissected aortic wall.

Conclusion

Accurate and timely differential diagnosis of acute chest pain is vital to ensure appropriate treatment. While AMI remains a leading cause of morbidity and mortality, conditions like pulmonary embolism, acute pericarditis, and aortic dissection present with similar symptoms and must be carefully considered. Utilizing a combination of clinical history, physical examination, ECG, biomarkers, and imaging modalities is essential for effective diagnosis and management.