Differential Diagnosis for ST Depression and T Wave Inversion

The presentation of ST depression in inferior and lateral leads along with T wave inversion in lateral leads suggests a cardiac origin, potentially related to ischemia or infarction. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Acute Coronary Syndrome (ACS): This is the most likely diagnosis given the ECG findings. ST depression and T wave inversion are indicative of myocardial ischemia, which is a hallmark of ACS. The involvement of inferior and lateral leads suggests that the ischemia may be related to a blockage in the right coronary artery or the left circumflex artery.

• Other Likely Diagnoses

  • Myocardial Ischemia without Infarction: This could be due to various factors such as coronary artery spasm, severe hypertension, or demand ischemia in the setting of severe anemia or tachycardia.
  • Cardiac Syndrome X: Characterized by chest pain with evidence of myocardial ischemia on ECG or stress testing but without significant coronary artery disease on angiography.
  • Hypertrophic Cardiomyopathy: Can cause T wave inversion and may mimic ischemic changes, especially in the lateral leads.

• Do Not Miss Diagnoses

  • Pulmonary Embolism: Although less common, pulmonary embolism can cause ECG changes including T wave inversion in the anterior leads and sometimes in the lateral leads, especially if there is associated right ventricular strain.
  • Aortic Dissection: Can cause chest pain and ECG changes mimicking ACS, including ST depression and T wave inversion, due to involvement of the coronary arteries or aortic root.
  • Pericarditis: May cause widespread ST elevation but can also present with ST depression and T wave inversion in some cases, particularly if there is associated myocardial involvement.

• Rare Diagnoses

  • Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Can cause T wave inversion in the right precordial leads but may also affect the lateral leads in advanced cases.
  • Left Ventricular Hypertrophy: Can cause secondary repolarization abnormalities including T wave inversion, especially in the lateral leads.
  • Myocarditis: Inflammation of the myocardium can cause a variety of ECG abnormalities including ST depression and T wave inversion, mimicking ischemic changes.

Each of these diagnoses requires careful consideration of the clinical context, including patient symptoms, physical examination findings, and additional diagnostic tests such as troponin levels, echocardiography, and coronary angiography.