This 61-year-old man underwent closure of a large primum atrial septal defect (2.5 cm in width and 2.9 cm in height) with a pericardial patch and repair of a long cleft of the mitral valve. The following ECG was recorded upon admission to the cardiac surgical ICU:

• AV Dissociation: sinus Rhythm (58/min) with a competing accelerated junctional rhythm (66/min)
• Two AV captures with a long PR interval (490 msec)
• ST elevation, consider pericarditis or injury

One day after his surgery, the following ECG was recorded:

• Sinus rhythm with first degree AV block (PR = 400 ms)
• ST elevation, consider pericarditis or injury

The following ECG was recored on post-operative day two:

• Atrial fibrillation with an accelerated junctional pacemaker (ventricular rate 64/min)
• AV dissociation, consider the possibility of complete heart block
• ST elevation, consider pericarditis or injury

The following ECG was recorded eight hours later on post-operative day 2:

• Atrial flutter with complete AV block
• Ventricular rate 49/min
• Diffuse ST elevation, compatible with acute pericarditis