This 41-year-old woman had been known to have severe mitral regurgitation secondary to mitral valve prolapse, and recently developed symptoms of congestive heart failure. Mitral valve repair was successfully carried out, and the following ECG was recorded one week later:

• Junctional bradycardia
• T wave abnormality, consider anterior ischemia

As the patient was on digoxin, the possibility of digitalis toxicity was considered. The serum digoxin level was found to be <0.3 nmol/L (therapeuthic level 1.0-2.6 nmol/L). Junctional rhythms are not uncommonly after cardiac surgery, and two days later, the patient was found to be in normal sinus rhythm. A coronary angiogram prior to surgery had been normal.