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12-Lead ECG and Patients with Syncopal Episodes (Case 4)

Posted by Jessica Carmichael on 9/17/12 11:20 AM

This is the fourth in a series of articles that will explore the cardiac causes of syncope and illustrate the importance of acquiring an ECG on all patients who experience presyncope or syncope.

Emergency Medical Services (EMS) personnel frequently respond to patients experiencing syncopal episodes. Syncope accounts for 3% of emergency department visits and 6% of hospital admissions yearly. Syncope is defined as the fainting or a brief loss of consciousness caused by transiently inadequate blood flow to the brain. EMS personnel often minimize the syncopal event and dismiss it simply as a sign of anxiety or a vasovagal reaction. Although increased vagal tone is often responsible for inadequate cerebral perfusion and subsequent loss of consciousness, it is critical to exclude the postural, neurologic, and cardiovascular causes first.

Case Study

You are dispatched to a local high school for a 28-year-old teacher who passed out in the middle of class. When you arrive on the scene, you find an adult female sitting in the health room with the nurse. The teacher is awake, alert, and oriented. She explains that she has experienced several fainting episodes over the last few weeks. She has an appointment to see her primary care doctor in a few days and insists she does not need medical care. She agrees to let you measure her vital signs and record an ECG prior to signing a refusal. Her vital signs are: blood pressure 124/62 mm Hg, pulse 80 beats/min, respirations 22 breaths/min, and SpO2 99%. She denies having chest pain but does remember feeling a little short of breath before passing out. You acquire the following ECG:


Reading the 12-Lead ECG

1. What is your interpretation?
2. Do you see anything that may be life-threatening or responsible for causing syncope?
3. What is your next course of action?
4. Does this patient need to be transported to the hospital?

Case Study Summary

The ECG illustrates a sinus rhythm. Close inspection of the tracing also reveals short PR intervals, wide QRS complexes, and delta waves, consistent with Wolf-Parkinson-White Syndrome (WPW). WPW is a genetic abnormality that affects approximately 0.3% of the population. WPW involves an accessory pathway between the right atrium and ventricle called the Bundle of Kent. Unlike the AV node, the Bundle of Kent is unable to prevent the transmission of electrical impulses received from the atria to the ventricles. As a result, any impulse that reaches the Bundle of Kent will travel directly to the ventricular tissue below, causing pre-excitation of the right ventricle. This unrestricted passage can sometimes induce supraventricular tachydysrhythmias (SVTs). Patients with SVT often experience fluttering in their chest, shortness of breath, or chest pain. Patients can also experience syncope at the onset of the tachydysrhythmias due to the sudden decrease in cardiac output.



This patient should be transported to the emergency department for further evaluation. Prehospital treatment includes continuous ECG monitoring and obtaining intravenous access. If the patient experiences SVT during transport, providers should follow ACLS guidelines for achieving rate control.

Clinical Pearls

  • Never dismiss unexplained syncope in the prehospital setting; it may be a symptom of a lethal disease.
  • Syncope is a high-risk chief complaint.
  • Syncope can be a result of a sudden increase or decrease in heart rate. Therapy is centered on rate control.
  • WPW is characterized by:
    • A delta wave
    • A short PR interval
    • A wide QRS complex
  • Consider transmitting any questionable ECG to the local emergency department physician, if possible.

Suggested Readings

Wolf-Parkinson-White Syndrome

Christopher Touzeau, MS, NREMT-P, RN, caught the EMS bug in 1992 and has been a professional firefighter paramedic in Montgomery County, Maryland since 1995. He developed a passion for teaching early in his career and has developed and taught EMS courses in numerous areas around the country and world.

Mr. Touzeau is the author of ECG Cases for EMS. Learn more about this resource

Topics: 12-lead ECG, 12-Lead, ECG, EMS

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