The <scp>S1Q3T3</scp> Electrocardiographic Abnormality as a Result of Massive Empyema due to Pyogenic Liver Abscess: A Case Report

The S1Q3T3 pattern on the electrocardiogram is often associated with right heart strain in pulmonary embolism, pneumothorax, and acute lung diseases causing acute cor pulmonale. The S1Q3T3 pattern during acute massive empyema in the setting of a liver abscess has not been reported in theliterature. We present a case report of a 41-year-old Iranian female patient with a sudden onset chest pain, dyspnea, sinus tachycardia, and electrocardiography findings of S1Q3T3 pattern, who was revealed to have an expanding pyogenic pleural effusion as a result of trans-diaphragmatic extension of a liver abscess. The other causes of S1Q3T3 were excluded. The patient underwent the insertion of a chest tube to remove the pus. After chest tube insertion, the S1Q3T3 pattern resolved. Despite initial improvement, the patient developed complications, including pleural adhesions and lung collapse, and required a posterolateral thoracotomy with decortication. This resulted in dramatic clinical improvement. Rapidly expanding massive pyogenic pleural effusion can lead to the S1Q3T3 pattern on the electrocardiogram.