Differential Diagnosis for S1Q3T3 EKG Pattern

The S1Q3T3 pattern on an electrocardiogram (EKG) is indicative of a specific set of conditions that affect the heart's electrical activity and structure. This pattern is characterized by a deep S wave in lead I, a deep Q wave in lead III, and an inverted T wave in lead III. Here's a differential diagnosis organized into categories:

• Single Most Likely Diagnosis

  • Pulmonary Embolism (PE): The S1Q3T3 pattern is classically associated with pulmonary embolism, although it's not highly sensitive. The pattern is thought to result from the acute right ventricular strain caused by the blockage of a pulmonary artery.

• Other Likely Diagnoses

  • Acute Cor Pulmonale: This condition, which involves right ventricular dysfunction due to pulmonary causes, can also present with the S1Q3T3 pattern due to similar mechanisms of right heart strain.
  • Chronic Pulmonary Hypertension: Long-standing elevated pressures in the pulmonary arteries can lead to right ventricular changes that might be reflected in the EKG as an S1Q3T3 pattern.

• Do Not Miss Diagnoses

  • Massive Pulmonary Embolism: While included in the broader category of pulmonary embolism, massive PE is particularly critical to identify due to its high mortality rate and need for immediate intervention.
  • Acute Myocardial Infarction Involving the Right Ventricle: Although less common, an MI involving the right ventricle can mimic the EKG changes seen in pulmonary embolism and is crucial to diagnose due to its implications for treatment and prognosis.

• Rare Diagnoses

  • Congenital Heart Diseases with Right Ventricular Hypertrophy: Certain congenital heart diseases can lead to right ventricular hypertrophy, potentially resulting in EKG patterns similar to S1Q3T3.
  • Tricuspid Stenosis: This valvular heart disease can cause right atrial enlargement and potentially lead to EKG changes that might resemble the S1Q3T3 pattern, although it's less common.
  • Chronic Thromboembolic Pulmonary Hypertension: A condition where chronic clotting in the pulmonary arteries leads to pulmonary hypertension, which can result in right heart strain and potentially the S1Q3T3 EKG pattern.