A 59-year-old man is at his family doctor’s for complaint of one week history of marked tiredness:

• Sinus rhythm with complete heart block
• Wide-QRS escape rhythm (right bundle branch block pattern) 
• Ventricular rate 39/min  

There is sinus rhythm with rate 67 min and a regular wide-QRS escape rhythm with rate 39/min. The two rhythms are dissociated because of third degree AV block. The distal pacemaker may be located in the junctional/common His bundle area (with right bundle branch block) or more distally, in the left ventricle. The slow ventricular rate (>40/min) favours the probability of an escape ventricular rhythm (usually, the more distal is the escape rhythm, the slower is its rate).