1. Stepwise interpretation of ECG ID 108 2 nd degree AV block Mobitz 1

2. ID 108 – 58 year old man in the emergency department

3. ID 108 – 58 year old man in the emergency department Can you see P waves?

4. Yes: there are regular P waves, that originate from the sinus node (rate 88/min) Are the P waves followed by QRS complexes? ID 108 – 58 year old man in the emergency department - Sinus rhythm, 88/min.

5. Yes, however, there is 2 nd degree AV block: 2 P waves are conducted with progressive PR prolongation and the third P wave is blocked ( Mobitz 1 second degree AV block ) Ventricular rate 59/min. ID 108 Sinus rhythm with 2 nd degree AV block (Mobitz 1) Ventricular rate 59/min

6. ID 108 – Sinus rhythm with 2 nd degree AV block (Mobitz 1) – Ventricular rate 59/min . Following diagnostic steps: - QRS axis is normal – The QRS duration is normal (no BBB or nonspecific block) - No right or left ventricular hypertrophy – No QRS signs of infarction- Normal ST segment and T waves

7. ID 108 Final diagnosis: - Sinus rhythm with Mobitz 1 second degree AV block (3:2 AV conduction) Ventricular rate 58/min. No other abnormalities