This EKG comes courtesy of Dr. Behseta.
A 66 year old female with a history of mental retardation and Parkinson’s, presents to the ED from a nursing home. The patient is not able to provide much history. The nursing home states they noticed the patient to be having difficulty breathing this morning. As per the family, there has been no recent fever, cough, chills, vomiting or diarrhea. Vital signs: Pulse 137, Respirations 26, BP 78/42, O2 sat 87% on a non-rebreather mask.
The EKG is below.
1. What does the EKG demonstrate?
2. How would you manage this patient?
The EKG shows sinus tachycardia with an incomplete right bundle branch block and an S1Q3T3 pattern. This is suggestive of a pulmonary embolism.
The diagnosis was confirmed with a CT which showed bilateral pulmonary emboli with right heart strain. The patient was treated with IV tPA.
Shortness of breath can be caused by many different things. In this patient with a limited history the diagnosis is based on physical exam and ancillary tests. The EKG can sometimes give us clues about different causes of shortness of breath.
Specifically in pulmonary embolism there are certain EKG patterns we look for. Sinus tachycardia is a very common rhythm in pulmonary embolism, but it is certainly not very specific. Other findings may suggest strain to the right side of the heart. Complete or incomplete right bundle branch block patterns may be seen. This includes a widened QRS complex with an RSR’ pattern in leads V1-V3, secondary T wave changes in leads V1-V3, and deep terminal S waves in leads V5, V6, I and aVL.
Another sign of right heart strain on EKG is known as the S1Q3T3 pattern. This consists of an increase in the size of the S wave in lead I, an increase in the size of the Q wave in lead III, and an inverted T wave in lead III.
Among ED patients with symptoms suspicious for pulmonary embolism, the S1Q3T3 pattern has a sensitivity of 8.5% and a specificity of 97.7% (Marchick et al. Ann Emerg Med 2010;55:331- 335.) Other EKG findings associated with pulmonary embolism include tachycardia, incomplete (16%) or complete (18%) right bundle branch block, Right axis deviation (9%), and precordial T-wave inversions. 18% have a normal EKG. (Nielsen et al. Changing Electrocardiographic Findings in Pulmonary Embolism in Relation to Vascular Obstruction. Cardiology 1989;76:274.)