Third-degree (complete) Heart Block – Example 2

Brandon Fainstad, MD

Objectives

Determine key features of a A-V dissociation to identify complete heart block

Teaching Instructions

Plan to spend 5 minutes familiarizing yourself ECG. Have the image pulled up on the presenting screen or monitor. Ask for a full read of the ECG. If the learner has not done so already, ask them to commit to a rhythm

Teaching point: Sinus rhythm is defined by “a p before every qrs and a qrs after every p”. If you have a qrs without a p there are premature ventricular contractions (PVCs) or ventricular escape. If you have a p without a qrs there is a second or third degree AV block. This is a third degree because there is complete dissociation. None of the p waves are conducted as evidence of a regular ventricular rate with the same morphology.

ECG

Official Read

Complete (third degree) AV block with an atrial rate around 65 and a ventricular rate around 40. Left axis deviation with a right bundle branch block and possible prior inferior infarct.

Take Home Points

References

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