A 51-year-old man with good exercise tolerance and no symptoms or abnormal findings on physical examination suggesting cardiac disease, is in the pre-op clinic prior to a scheduled urology procedure:

• Accelerated junctional rhythm
• Atrial rate 85/min. – PR 90 msec
• No other abnormalities

When the P waves are negative in the inferior leads, the PR is less than 120 msec and the rate greater than 65/min the ECG diagnosis of accelerated junctional rhythm is usually made. In this case of a 51 year old man with no symptoms or signs of cardiac disease we may, however, actually be dealing with an ectopic atrial rhythm originating from the low atrium.