Relationship between the type of atrial fibrillation and thromboembolic events

Atrial fibrillation (AF) increases the risk for ischemic stroke and other thromboembolic (TE) events. Aim of the study was to examine the relationship between clinical types of atrial fibrillation (AF) and (TE) events. This longitudinal, observational study included patients with nonvalvular AF as main indication for in-hospital and/or outpatient treatment in the Cardiology Clinic, Clinical Center of Serbia during a period 1992-2007. The treatment of AF was based on the International Guidelines for diagnosis and treatment of AF, correspondent to given study period. Clinical types of AF were defined according to the latest ACC/AHA/ESC Guidelines for AF, from 2006. Diagnosis of central and systemic TE events during a follow-up was made exclusively by the neurologist and vascular surgeon. During a follow-up of 9.9 +/- 6 years, TE events were documented in 88/1 100 patients (8%). In the time of TE event 46/88 patients (52.3%) had permanent AF. The patients with permanent AF were at baseline significantly older and more frequently had underlying heart disease and diabetes mellitus. Cumulative TE risk during follow-up was similar for patients with paroxysmal and permanent AF, and significantly higher as compared to TE risk in patients with persistent AF. However, multivariate Cox proportional hazard regression analysis with independent variables clinical types of AF at baseline and in the time of TE event, clinical and echocardiographic characteristics and therapy for prevention of TE complications at baseline and at the time of TE event, did not reveal independent predictive value of clinical type of AF for the occurrence of TE events during a follow-up. TE risk in patients with AF does not depend on clinical type of AF. Treatment for prevention of TE events should be based on the presence of well recognized risk factors, and not on the clinical type of AF.