Dawn's picture
Submitted by Dawn on Thu, 11/15/2012 - 23:15

This ECG was obtained from an elderly woman who suffered a complete right coronary artery occlusion and inferior wall M.I.  In her case, the AV node was also affected, and she developed a third-degree AV block with a junctional escape rhythm.  A good ECG for ACLS classes as well as for ECG classes.  A lively discussion can be had regarding "types" of complete heart block and the nature of the escape rhythm - when to treat and when to leave the rhythm alone.  In this case the rate of the junctional escape rhythm was adequate for perfusion, and the patient's blood pressure was stable. Priority for treatment in this situation is restore blood flow through the coronary artery, if the patient is a candidate for PCI.  You might want to review Christopher Watford's contribution to the Ask the Expert page on AVB vs. AV Dissociation.

Related Terms: 
AV Block
Inferior Wall M.I.
Third-degree AV block
Complete AV block
AV dissociation
Junctional escape rhythm
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ekgpress@mac.com's picture

Submitted by [email protected] on Fri, 11/16/2012 - 05:51

Nice example by Dawn of an acute inferior MI with 3rd degree AV block and junctional escape rhythm. Clues that the "culprit lesion" is proximal RCA occlusion are: i) that ST elevation in lead III > lead II; and ii) the marked ST depression in lead aVL (that is more than is seen in lead I ). Additional points of interest include:

  • Likely posterior involvement (positive "mirror test" in leads V2).
  • Incomplete RBBB (qR' in V1 becoming an rSr' in V2 with narrow S in leads I,V6). This could be important in that new complete RBBB in association with acute MI is often a marker of significant conduction system damage.
  • Perhaps right ventricular involvement? Right-sided leads would be needed to know for sure - but acute RV involvement is a common accompaniment of proximal RCA occlusion - and the finding of an isoelectric (if not slightly elevated) ST segment here in lead V1 with ST-T depression by V2,V3 in association with acute infero-postero MI suggests RV involvement is likely. Fortunately - hemodynamics are normal (despite 3rd degree with AV nodal escape).

THANKS Dawn for posting this highly illustrative tracing!

Ken Grauer, MD  www.kg-ekgpress.com   [email protected] 

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