Atrial fibrillation is a growing health problem and the most common cardiac 
arrhythmia, affecting 5% of persons above the age of 65 years. The number of 
hospital discharges for atrial fibrillation has more than doubled in the past 
decade. It occurs very often in patients with congestive heart failure and the 
prevalence increases with the severity of the disease. These two conditions seem 
to be linked together, and congestive heart failure may either be the cause or 
the consequence of atrial fibrillation. The prognosis of atrial fibrillation is 
controversial, but studies indicate that atrial fibrillation is a risk factor in 
congestive heart failure patients. In the last 10-15 years, significant advances 
in the treatment of heart failure have improved survival, whereas effective 
management of atrial fibrillation in heart failure patients still awaits similar 
progress. Empirically, two strategies have evolved for treatment of atrial 
fibrillation: 1) rhythm control, which means conversion to sinus rhythm and 
maintenance of sinus rhythm; and 2) rate control, which means reduction of heart 
rate to an acceptable frequency. It is unknown whether one of these strategies 
is better than the other. In this review the authors discuss the prevalence, 
impact, and treatment of atrial fibrillation in heart failure patients.