First degree AV block II

Electrocardiogram of lead II showing normal sinus rhythm, first degree atrioventricular block with a markedly prolonged PR interval of approximately 0.40 seconds, and a widened QRS complex (0.16 seconds) due to concurrent left bundle branch block.

Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright.