Differential Diagnosis for Mid and Left Precordial Repolarization Disturbance on ECG

• Single Most Likely Diagnosis
  • Early Repolarization Syndrome: This condition is characterized by an elevation of the QRS-ST junction (J-point) often accompanied by a slight ST elevation in the leads where the repolarization disturbance is noted, commonly seen in healthy individuals, particularly in men.
• Other Likely Diagnoses
  • Myocardial Ischemia: Repolarization abnormalities can be a sign of ischemia, especially if the changes are new or dynamic. This could be due to coronary artery disease or other causes of reduced blood flow to the heart muscle.
  • Left Ventricular Hypertrophy (LVH): LVH can cause repolarization abnormalities due to the increased thickness of the left ventricular wall, leading to changes in the electrical activity of the heart.
  • Pericarditis: Inflammation of the pericardium can cause diffuse ST elevation or repolarization disturbances on the ECG, although it typically involves more leads than just the mid and left precordial leads.
• Do Not Miss Diagnoses
  • Acute Coronary Syndrome (ACS): Although myocardial ischemia is listed under other likely diagnoses, ACS (including myocardial infarction) is a critical condition that must not be missed due to its high morbidity and mortality. The presentation can sometimes be atypical, especially in women or diabetic patients.
  • Hypokalemia: Severe potassium deficiency can lead to significant repolarization abnormalities, including T wave flattening or inversion, and can be life-threatening if not corrected promptly.
• Rare Diagnoses
  • Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Although more commonly associated with right ventricular involvement, some forms of ARVC can present with left ventricular dysfunction and ECG changes, including repolarization disturbances in the mid and left precordial leads.
  • Cardiac Sarcoidosis: This condition can cause various ECG abnormalities, including repolarization disturbances, due to granulomatous infiltration of the heart muscle. It is less common but should be considered in the appropriate clinical context.