Stepwise interpretation of ECG

ID 168Left bundle branch block

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

There is no right ventricular hypertrophy or left ventricular hypertrophy

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

Can you see P waves?

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

Yes. There is sinus rhythm, 88/min. Each P is followed by a QRS complex, with a constant P-Rinterval (140 msec)

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

There are no signs of right or left atrial enlargement

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

The QRS duration is prolonged (145 msec.), with a pattern of Left Bundle Branch Block (LBBB)

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

The presence of LBBB precludes the diagnosis of left ventricular hypertrophy and usually masks an underlying myocardial infarction

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

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)

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

ID 380 – Final diagnosis: Normal Sinus rhythm, 88/min. Left bundle branch block.