Answer Tracings Vol 1.2


Allison Loynd          Marjan Siadat       Richard Gordon

David Mishkin         Brian Kern



ECG Interpertation

  • anterolateral wall STEMI
  • ST-elevation in leads I, AVL and precordial leads V2-V6.
  • Evolving Q waves are seen in several leads.

There is, in addition, complete heart block (CHB). The atrial rate is 125 bpm, while the ventricles are beating at 52 bpm. The arrows in ECG#2 show P waves (except the 8th P wave, which is buried in a QRS complex) marching through the QRS complexes.

Remember: you have AV dissociation but NOT CHB if the atria and ventricles are dissociated BUT the ventricular rate is FASTER than the atrial rate.


CHB occurs in about 5% of STEMIs. When it occurs in association with anterior wall MI, the prognosis is grave with mortality as high as 70-80%. This apparently is not causally related to the CHB itself but reflects that large MIs, which have worse outcomes, are more likely to have associated CHB.

In this case the patient was taken rapidly from the ED to the cath lab, where the LAD was found to have a proximal ruptured plaque with thrombus resulting in a 99% stenosis. This was successfully stented. A large troponin leak peaked at >22.78.

Although complete heart block with STEMI is generally considered to be an indication for at last temporary pacemaker placement, in this case after stenting the heart block resolved and it was felt that the patient did not need a pacemaker.

Echocardiogram on the 2nd hospital day showed a small LV cavity with concentric hypertrophy, severe hypokinesis of the mid
to distal and anterior septal wall, and akinesis of the apex. Ejection Fraction was 35%.

The patient was discharged home on the 4th hospital day.

Tracings is a learning module involving actual cases of patients and their ECGs that present to the Emergency Department.  Topics chosesn are dervied from the EM Model for Resident Education. Cases are prepared by Dr. William Berk.

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