EKG of the Week 2017 5-14

This EKG comes courtesy of Dr. Altberg.

A 17 year old male presents to the ED for a seizure. He has never had seizures before. He is currently awake and alert with normal vital signs.

His EKG is below.

1.       What does the EKG demonstrate?

2.       Does this explain the patient’s seizure?

 

ANSWER:

The EKG demonstrates WPW.

WPW can cause arrhythmias which can look like seizures.

 

The EKG demonstrates a sinus rhythm at a rate of approximately 55. The PR interval is approximately 0.10 seconds. There is a delta wave, best visualized in leads V4, V5, V6, II, and aVF. This is consistent with WPW.

WPW is a syndrome of pre-excitation of the ventricles. There is a by-pass tract connecting the atrium and the ventricle which can by-pass the AV node. Normally, when an impulse conducts down the normal conduction system, there is a delay as it passes through the AV node. When an impulse conducts down the by-pass tract, the impulse is not slowed down as it would be if it went through the AV node. So, the amount of time it takes the impulse to get from the atrium to the ventricle is shorter. This is reflected on the EKG by a short PR interval. Once the impulse leaves the bypass tract, it must travel through ventricular myocardium until it reaches normal conduction tissue. So, the impulse travels slower than normal impulses, and is reflected on the EKG by a delta wave and a wide QRS complex.

Patients with WPW are susceptible to tachyarrhythmias. SVT is the most common arrhythmia.

Arrhythmias can cause syncope with some shaking and this may mimic a seizure. So, keep arrhythmia in your differential of patients who present with seizure, especially new onset. As Dr. Reich teaches us, always do an EKG in a patient with new onset seizure.