Chronic atrial fibrillation (A fib) has an incidence of 0.4% in the general population (approximately 10% of those more than 60 years of age) and many of these patients are admitted to intensive or intermediate care units for reasons unrelated to this diagnosis. Chronic A fib needs to be clearly differentiated from new-onset A fib since the treatment and management strategies will differ.

Since chronic A fib or paroxysmal A fib has a very low likelihood of converting to sinus rhythm and remaining in sinus, the primary strategy is rate control with agents that slow conduction through the atrioventricular (AV) node so that the patient does not experience a rapid ventricular response that may severely compromise cardiac output. Patients with A fib already have lost approximately 20% of their diastolic filling secondary to the loss of coordinated “atrial kick” at end diastole. A rapid heart rate that compromises diastolic filling time further can thus compromise cardiac output to the point of shock. This may especially be true with patients who have diastolic dysfunction secondary to aortic stenosis and chronic hypertension. Commonly used agents include beta-blockers or calcium channel blockers. Digoxin was a mainstay of treatment in the past but is much less commonly used currently.