This 79-year-old man had a myocardial infarction at age 71. He has been stable with infrequent angina since. He is seen in the cardiac clinic because on the previous day he had an episode of syncope:

• Sinus rhythm with high grade AV block
• Occasional AV capture with prolonged PR
• The conducted QRS complexes show incomplete right bundle branch block (iRBBB) and anterior myocardial infarction (QS in V3 and V4)
• Ventricular escape pacemaker with rate 35/min and left bundle branch block pattern