Thromboembolic risk in atrial flutter - The FLASIEC (Flutter Atriale Societa Italiana di Ecografia Cardiovascolare) multicentre study

Aims Patients with atrial flutter are believed to be at lower risk of throm boembolism than patients with atrial fibrillation. However, the incidence o f atrial thrombi and the need for anticoagulation in patients with atrial f lutter is not well established. Methods and Results A prospective observational multicentre study was under taken to assess the frequency of atrial thrombi and spontaneous echocontras t and the prevalence for aortic complex atherosclerotic lesions in a cohort of unselected patients with atrial flutter. We evaluated 134 patients (102 male, aged 70 +/- 9 years); exclusion criteria were history of atrial fibr illation, rheumatic mitral valve disease and mitral mechanical prosthesis. The median of atrial flutter duration was 33 days. Twelve patients had been taking warfarin for more than 7 days. One hundred and twenty-four patients (94%) underwent a transoesophageal echocardiogram, which revealed left atr ial appendage thrombi in two patients (1-6%) and right atrial thrombi in on e patient At least moderate left atrial echocontrast was found in 16/124 pa tients (13%). Complex atherosclerotic aortic plaques were detected in 10 pa tients (8%). Atrial flutter conversion was attempted in 93/134 patients (69 %). At the 1-month follow-up, two patients experienced a thromboembolic eve nt following restoration of sinus rhythm. Conclusions Atrial thrombi and echocontrast, and complex aortic atheroscler otic plaques are relatively uncommon in patients with atrial flutter. Post- cardioversion embolism was observed in two patients in our study population .