Atrial fibrillation as a new independent risk factor for thromboembolic events: hemodynamics and vascular consequence of long ventricular pauses.

Background: Atrial fibrillation (AF) is a leading risk factor of arterial thromboembolic events. Aim is to study the main arteries hemodynamics and kinetics in AF and to propose the functional classification of AF.

Methods: We included 188 patients (80 as the control). We performed 24-hours ECG monitoring, blood lipids analysis, echocardiography, stress echocardiography, coronary angiography, renal arteries angiography, ultrasound Doppler of brachiocephalic arteries, abdominal aorta branches, renal arteries, lower extremities arteries, sphygmography. Patients were divided into 3 groups up to the duration of maximum pauses between ventricular complexes in AF: 1) with a pause <1 second (64); 2) with a pause of ≥1, but <2 seconds (62); 3) ≥2 seconds (62). We analyzed the thromboembolic events within 1 year.

Results: We observed the increase of linear blood flow velocity and volume flow in patients with AF during the spreading of the wave after a long pause between ventricles' contractions. The longer the pause between the ventricles' contractions, the more increase of arteries kinetics parameters is observed. The most frequent incidence of thromboembolic events within 1 year was in group 3.

Conclusions: We propose a functional classification of AF: 1) AF with the pauses of less than 1 second; 2) more 1, but less than 2 seconds; and 3) 2 or more seconds. The most unfavorable is AF with pauses of 2 seconds or more. We supplemented the CHA2DS2-VASc Score with the new independent risk factor - type of AF - in accordance with the maximum duration of pauses between cardiac cycles.