13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-143

Effects of anticoagulant therapy in patients with atrial fibrillation and intra-atrial thrombosis

Alberto Menotti, Ferdinando Imperadore, Giuseppe Vergara, Marcello Disertori*.
Department of Cardiology, Rovereto Hospital, Rovereto,
*Department of Cardiology, S. Chiara Hospital, Trento, Italy

Introduction

Atrial fibrillation is the most common arrhythmia and predisposes a person to significant increase of systemic embolism¹. The risk of systemic embolism is due to the lack of an effective atrial contraction that results in blood stasis and the formation of potentially embolic atrial thrombi. Cardioversion from atrial fibrillation to sinus rhythm is commonly performed, but, in absence of anticoagulation, cardioversion is associated with clinical thromboembolism in 3-7% of patients^2-4. The use of anticoagulation with warfarin for 3 to 4 weeks before cardioversion is associated with a reduction in cardioversion-related thromboembolism to 0% to 1.6%^2-4.

The mechanism by which warfarin conveys this beneficial effect on patients with atrial fibrillation was thought to be due to the adherence of the thrombus to the atrial endocardium, thus reducing the likelihood of dislodgment⁵. Recently some authors have suggested that the thrombus resolution rather than organization can be the prevalent mechanism⁶.

Transesophageal echocardiography is both sensitive and specific^7-9 for the identification of atrial thrombi and offers the opportunity to serially evaluate atrial thrombi before and after anticoagulant therapy.