What abnormal EKG change is associated with a pulmonary embolism?

The association of the S1Q3T3 pattern with pulmonary embolism is well-documented and reflects specific changes seen on an electrocardiogram (EKG) due to the acute strain placed on the right side of the heart. In this pattern, S waves are noted in lead I, Q waves in lead III, and inverted T waves in lead III. This triad of findings is indicative of right heart strain, which occurs in the setting of a pulmonary embolism as the right ventricle faces increased pressure to pump blood through obstructed pulmonary vessels.

The presence of this EKG change serves as an important diagnostic clue when considering a patient’s history and clinical presentation, especially in the context of sudden onset dyspnea, chest pain, or risk factors for venous thromboembolism. The S1Q3T3 pattern, while not exclusive to pulmonary embolism, strongly suggests it and can aid in the overall assessment of the condition alongside other clinical and diagnostic tests.

Additionally, while ST elevation, QRS widening, and bradycardia can occur in various cardiac conditions or in response to different forms of stress, they are not characteristic of pulmonary embolism and therefore, do not provide the same specific insight into the presence