In vitro atrial flow dynamics: normal conditions versus atrial fibrillation.
OBJECTIVE
The flow dynamics in the atrium is poorly described. The reasons are principally due to the complicated geometry of the cavity and its contractility. The present in vitro study focuses on the description of the flow in the left atrium in normal conditions (NC) and in atrial fibrillation (AF). The final objective is to give leads to understand, from the hemodynamic point of view, complications in case of AF.


RESULTS
An atrio-ventricular dual activation system is used to simulate physiological flow in the left atrium. The cavities are compliant and transparent. Velocity measurements are performed with Particle Image Velocimetry. Systolic peak of the pulmonary venous flow is about 0.4 m s(-1) and diastolic peak 0.6 m s(-1) in magnitude. Vortices appear during diastasis and systole and are of normal size and duration. In early and late diastole, the ventricular filling (in NC and AF) and the atrial contraction (in NC only) create a characteristic flow pattern that consists in directed flow towards the mitral valve. In AF an increased resident time (500 ms versus 300 ms) and a slow helical flow pattern (about 0.1 m s(-1)), similar to what is measured using ultrasound echocardiography are observed.


CONCLUSIONS
This study uses atrial flow dynamics description to help understand why thromboembolisms occur in AF.
Mouret
Frederic
F
Cardiovascular Biomechanics Team, IRPHE-UMR CNRS 6594, EGIM, I.M.T., Technopôle de Château-Gombert, 13383 Marseilles 13, France.
Garitey
Vincent
V
Bertrand
Eric
E
Derivaux
Frederic
F
Fuseri
Jean
J
Rieu
Regis
R
D001281:Atrial Fibrillation; D016275:Atrial Function; D004452:Echocardiography; D006801:Humans; D066298:In Vitro Techniques; D011667:Pulmonary Veins / Q000502:physiology; D012039:Regional Blood Flow