Atrial fibrillation is the most commonly sustained
cardiac arrhythmia and a common reason for mortality and morbidity.
Atrial fibrillation causes disease for three reasons: i) the ventricular rate is often high, which leads to symptoms ranging from discomfort to life threatening
heart failure; ii) the rhythm causes loss of atrioventricular synchrony, which reduces diastolic filling and may lead to
heart failure; and iii) atrial contraction is lost leading to stagnant blood that again may lead to atrial thrombi and peripheral
embolism. Thus, the treatment of
atrial fibrillation is focused on the maintenance of sinus rhythm, rate control and prevention of
embolism. For the maintenance of sinus rhythm, all drugs under current development are
potassium channel blockers; the so-called class III
anti-arrhythmic drugs. Those which have been further investigated appear to be valuable for maintenance of sinus rhythm but all carry a significant risk of pro-
arrhythmia, in particular Torsade de Pointe
ventricular tachycardia. Rate control has been a focus of treatment for many years and several very old drugs, including
digoxin, are used for this. There is, to the author's knowledge, no current effort for evaluating new drugs for this indication. Prevention of
embolism has for many years been obtained with
vitamin K antagonists for which the clinical evidence is overwhelming. Previous attempts to replace
vitamin K antagonists with
aspirin have not been fruitful. A large number of newer anticoagulation regimes are in development, but to the author's knowledge only a single
thrombin inhibitor is actively being developed for
atrial fibrillation.