Atrial flutter--update on the mechanism and treatment.

Atrial flutter is a common and usually benign but symptomatic supraventricular tachycardia. There is a striking similarity between patients with atrial flutter suggesting a common substrate despite the presence or absence of underlying heart disease. In man, the mechanism is a single reentrant circuit originating in the right atrium whose center appears to be functional within the anatomical constraints of the right atrium. The reentrant circuit of atrial flutter contains an area of slow conduction in the inferior right atrium but the size and exact location is uncertain. Drug therapy directed at terminating and preventing atrial flutter has been available for many years. The efficacy and safety of this therapy is not as well tested as is the same therapy for atrial fibrillation. The most effective way to terminate atrial flutter is a nonpharmacological approach. Several nonpharmacological methods provide new treatment options in the management of patients with drug resistant or hemodynamically unstable atrial flutter. The use of anticoagulation for this disorder is still evolving. There is a risk of clinically apparent thromboemboli in some patients with atrial flutter although the risk appears less than that for atrial fibrillation. In the future, refinements and improvements in therapy for atrial flutter will likely be derived from a better understanding of its mechanism.