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Jason's Blog: ECG Challenge of the Week for July 15-22. What has happened here?

jer5150's picture

Patient’s clinical data:  Symptomatic 49-year-old white man who presented to the emergency department (ED) with left-sided chest pain.

At the time of admission, there were two consecutive 12-lead ECGs initially performed in the ED.  The above ECG was the second of the two that was performed.   Why would there be a mandatory need to perform a minimum of two ECGs on this type of a patient?   

** *** Both of these images are from the same patient.  Please note that the patient’s chest film was performed correctly and is anatomically accurate (i.e., situs solitus) *** **

I’ve included the chest X-Ray (CXR) because it, by far, provides more clarity than an ECG alone ever could.

(1.)  What emergent event has brought this patient to the emergency department?
(2.)  What has produced this unusual combination of QRS axis and precordial pattern?

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jer5150's picture
Submitted by jer5150 on

The 12-lead ECG was performed in the emergency department on a patient having an acute inferior infarction. Initially, the technician performed a "standard" ECG. Upon completion of the first ECG, the tech was either instructed by an ED physician to perform a second ECG to obtain a right-sided series or they had a standing protocol to do so in the event a patient presented with this specific type of infarction. WHAT THEY DID RIGHT: The tech correctly placed the precordial electrodes and attached the cables so that they are now monitoring leads V1R through V6R (a full rather than a partial right-sided series). This was done in an attempt to determine if there is any right ventricular (RV) involvement (esp. in leads V3R and V4R). WHAT THEY DID WRONG: The tech needlessly switched the right arm and left arm cables so that the overall ECG now superficially mimics a patient with mirror-image dextrocardia having an acute inferior infarction while having their ECG configured in a convention "standard" placement. In the ECG, lead II is really lead III and lead III is really lead II. Leads aVR and aVL are also transposed. Lead I is, or course, inverted. The tech probably knew that there are two primary occasions when you perform a right-sided series and they got confused. There was no reason for them to reverse the RA and LA cables.

Jason E. Roediger - Certified Cardiographic Technician (CCT)
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