1. ID 380 – 53 year old man in the pre-anaesthesia clinic

2. ID 380 – 53 year old man in the pre-anaesthesia clinic Can you see P waves?

3. ID 380 – 53 year old man in the pre-anaesthesia clinic Yes: The P waves originate from the sinus node– The rhythm is regular – Each P is followed by a QRS - The PR interval is normal – The rate is 60/min NORMAL SINUS RHYTHM, 60/min

4. ID 380 - NORMAL SINUS RHYTHM, 60/min There are no signs of left atrial enlargement or right atrial enlargement

5. ID 380 - NORMAL SINUS RHYTHM, 60/min Let’s now look at the QRS complexes: There is normal QRS axis (between 0 and 90 degrees)

6. ID 380 - NORMAL SINUS RHYTHM, 60/min The QRS duration is normal : There is no right bundle branch block, left bundle branch block or non-specific block

7. ID 380 - NORMAL SINUS RHYTHM, 60/min There is no right ventricular hypertrophy or left ventricular hypertrophy

8. ID 380 - NORMAL SINUS RHYTHM, 60/min There are no QRS signs of myocardial infarction – There are normal ST segment and normal T waves

9. ID 380 - Final diagnosis: NORMAL SINUS RHYTHM, 60/min NORMAL ECG