1. Stepwise interpretation of ECG
ID 175

2. ID 175 – 58 year old man followed in the Cardiac Clinic because of coronary artery disease

3. ID 175 – 58 year old man followed in the Cardiac Clinic because of coronary artery disease
Can you see P waves?

4. ID 175 – Normal sinus rhythm, 88/min.
Yes. There is sinus rhythm, 88/min. Each P is followed by a QRS complex, with a constant P-
R
interval (140 msec)

5. ID 175 – Normal sinus rhythm, 88/min.
There are no signs of right or left atrial enlargement

6. ID 175 Normal Sinus rhythm, 88/min.
Left bundle branch block
The QRS duration is prolonged (145 msec.), with a pattern of Left Bundle Branch Block (LBBB)

7. ID 165 Normal Sinus rhythm, 88/min.
Left bundle branch block
The presence of LBBB may mask the diagnosis of left ventricular hypertrophy and/or
myocardial infarction

8. ID 165 Normal Sinus rhythm, 88/min.
Left bundle branch block
In left bundle branch block the abnormal depolarization is usually associated with secondary
abnormal repolarization (ST depression and negative T in the leads showing a broad R wave)

9. ID 165 Final diagnosis: Normal Sinus rhythm, 88/min.
Left bundle branch block

10. ID 165 Final diagnosis: Normal Sinus rhythm, 88/min.
Left bundle branch block