[Epidemiology of atrial fibrillation]

FREQUENCY: Atrial fibrillation is the most frequent sustained arrhythmia, especially in the elderly. The incidence accounts for 2% past the age of 40 years, 6% over 70, an approximately 15% over 90 years old.

Primary cause in "idiopathic" atrial fibrillation is differentiated from secondary causes of cardiac and non-cardiac origin. Important predictive cardiovascular diseases to develop atrial fibrillation are coronary heart disease, hypertension or rheumatic heart disease. Electrophysiological mechanism behind atrial fibrillation is a reentry circuit. The clinical symptoms are influenced by the conducted ventricular heart rate and the loss of atrial contraction.

The need for a therapeutic approach--either for recurrence of sinus rhythm or heart rate control--is mainly determined by the quality of life. Quality of life, functional capacity and maximum oxygen consumption are improved if sinus rhythm is reestablished. Finally, mortality is double as high if atrial fibrillation is present. Whether mortality is directly influenced by atrial fibrillation or fibrillation is considered as more or less the subsequent arrhythmia for an underlying disease is still under investigation.