EKG of the Week 2019 7-28

This EKG comes courtesy of Dr. Khodorkovsky.

A 91 year old female with a history of HTN and a pacemaker, presented for chest pain x 45 minutes. It was described a s “It feels like somebody is sitting on my chest”.

The EKG is below:

2019 7-28.jpg

The patient’s previous EKG is below:

2019 7-28 previous EKG.jpg

1.      What does the current EKG demonstrate?

2.      How would you manage this patient?

ANSWER:

The EKG shows a paced rhythm with concordant ST elevations in lead aVL and possibly lead I, and concordant ST depressions in leads V3, V6, III and aVF.

 This EKG is concerning for an acute coronary occlusion. The patient should be sent to the cath lab.

 

 

Identifying STEMI in the setting of a paced rhythm can be very challenging. Sgarbossa described criteria which are specific for the early diagnosis of MI (Sgarbossa et al. Am J Cardiol. 1996 Feb 15;77(5):423-4; Sgarbossa et al. NEJM 1996;34:481-7). These criteria are:

Sgarbossa's criteria.jpg

In a normal paced rhythm or a “normal” left bundle branch block, there are “normal” ST depressions and ST elevations. However, the ST elevations typically go in opposite direction to the QRS complex. These are called discordant changes. For example, in the patient’s old EKG, leads V1-V6 demonstrate negative QRS complexes with ST elevations. Leads I and aVL demonstrate positive QRS complexes with ST depressions.

However, our patient’s current EKG demonstrates concordant ST elevations in lead aVL and possibly I. The QRS complex is positive and the ST segments are elevated. This is consistent with Sgarbossa’s first criterion. There are also concordant ST depressions in leads V3, V6, III and aVF. The QRS complexes are negative and the ST segments are depressed. Although the depressions in leads V6, III and aVF are not one of the Sgarbossa criteria, they likely represent a reciprocal change. The concordant ST depression in lead V3 meets the second Sgarbossa criterion. This EKG is clearly changed from the patient’s previous EKG which demonstrated a normal paced morphology.

Our patient’s initial troponin was negative. The second troponin was 3.4. This EKG represents an acute MI in the presence of a paced rhythm.