This 81-year-old man had a myocardial infarction at age 75. He had angioplasty and stenting of his LAD and circumflex arteries and has been stable with infrequent angina since. He is seen in the cardiac clinic because of an episode of syncope that lasted a few seconds:

• Sinus rhythm with Mobitz II second degree AV block
• Left axis deviation
• Right bundle branch block
• Inferior infarct, age undetermined, Cannot rule out anterior infarct
• Marked ST abnormality, consider anterolateral ischemia

Comments: In patients with Mobitz II second degree AV block the first PR interval after a pause may be slightly shorter (because the conduction through the AV node is faster after the longer pause). The subsequent PR intervals do not show progressive prolongation.