This document discusses the stepwise interpretation of an ECG for a patient. It identifies that the patient, a 56-year-old man who had an episode of syncope, has sinus rhythm with complete heart block. The atrial rate is 80/min while the ventricular rate is 43/min, showing dissociation between the two rhythms. The QRS complexes originate from the AV junction at a rate of 43/min, indicating an escape junctional rhythm. The final diagnosis is sinus rhythm with complete heart block and an escape junctional rhythm supplying the ventricles.

1. Stepwise interpretation of ECGID 111Complete heart block

2. ID #111 – 56 year old man who had an episode of syncope

3. ID #111 – 56 year old man who had an episode of syncope Can you see P waves?

4. ID #111 - 56 year old man who had an episode of syncopeYes, there are sinus P waves, rare 80/min.Are the waves followed by QRS complexes?

5. ID #111 - Sinus rhythm with complete heart block –P rate 80/min, QRS rate 43/min No – The rhythm of the P waves and the rhythm of the QRS complexes are regular, but the two rhythms are dissociated. The atrial rate is 83/min, the ventricular rate 50/min There is complete heart blockAs atria and ventricles are dissociated, where is the activation of the ventricles coming from?

6. ID #111 - Sinus rhythm, with complete heart block – Sinus rate 80/min. Escape junctional rhythm. Ventricular rate 43/min.The QRS complexes are narrow – The escape pacemaker is in the area of the AV junction

7. ID #111 - Sinus rhythm, with complete heart block – Sinus rate 80/min. Escape junctional rhythm. Ventricular rate 43/min.The QRS axis is normal (near 0 degrees). There is no bundle branch block or non-specific blockNo LVH or QRS signs of myocardial infarction. The ST segment and T waves are normal.

8. ID #111 Final diagnosis: Sinus rhythm, with complete heart block – Escape junctional rhythm. Ventricular rate 43/min.