This 76-year-old-woman has experienced palpitations and dyspnea since two months ago. She had no previous cardiac complaints. She reports that her family doctor prescribed her a medication that led to an improvement of her symptoms, and that she is now able to do moderate housework without discomfort:

• Atrial Fibrillation with a controlled ventricular rate (66/min)
• No other ECG abnormalities

When the patient first saw her family doctor, she was found to be in atrial fibrllation with a rapid ventricular response (130/min). She was started on digoxin, and later added a beta-blocker. With slowing of her ventricular rate, the patient rapidly improved, and was able to resume her normal activities. Further investigations demonstrated no other cardiac abnormalities. 

Atrial fibrillation is a common arrhythmia in elderly patients, with or without evidence of structural heart disease.