An impairment of the left atrial function similar to that one generally observed by
echocardiography in atrial fibrillation (AF) has been reported in patients with patent
foramen ovale (PFO) and permanent right-to-left shunting (RLS) [
- Rigatelli G.
- Aggio S.
- Cardaioli P.
- Braggion G.
- Giordan M.
- Dell'avvocata F.
- et al.
Left atrial dysfunction in patients with patent foramen ovale and atrial septal aneurysm:
an alternative concurrent mechanism for arterial embolism?.
]. Computational fluid dynamic (CFD) studies have suggested that in left atrial appendage
(LAA) vortices generated in the chamber remain high strengths and with longer durations
in patients with AF, inducing ineffective emptying of the blood in the atrium and
appendage, which then lead to blood stagnation and subsequent thrombus formation [
- Koizumi R.
- Funamoto K.
- Hayase T.
- Kanke Y.
- Shibata M.
- Shiraishi Y.
- et al.
Numerical analysis of hemodynamic changes in the left atrium due to atrial fibrillation.
]. Moreover, atrial wall movement by high-frequency fibrillation had a large impact
on the stagnation of blood flow. The relative residence time, which is an indicator
of stagnation of blood flow, increase in the upper part of the LAA during AF. Atrial
vulnerability and atrial abnormalities such as PFO and atrial septal aneurysm have
been suggested to be associated in patients with cryptogenetic stroke [
- Berthet K.
- Lavergne T.
- Cohen A.
- Guize L.
- Bousser M.G.
- Le Heuzey J.Y.
- et al.
Significant association of atrial vulnerability with atrial septal abnormalities in
young patients with ischemic stroke of unknown cause.
]. An anti-arrhythmic effect has been postulated for transcatheter PFO closure [
- Ernst G.
- Stöllberger C.
- Abzieher F.
- Veit-Dirscherl W.
- Bonner E.
- Bibus B.
- et al.
Morphology of the left atrial appendage.
]. In the present manuscript, we want to characterize by means of CFD analysis the
fluid dynamic profile of patients with mild RLS and permanent RLS evaluating if similarities
with the fluid dynamic profile of patients with AF do eventually exist. The geometrical
model of the right atrium (RA), left atrium (LA), left atrial appendage (LAA) and
PFO has been constructed based on the collective data acquired using cardiac Magnetic
Resonance Imaging in 100 patients (mean age 39.5 ± 7.4 years) with permanent RLS or mild RLS on transesophageal echocardiography investigated
as part of PFO management program in our institution. Specifically, the entire domain
has been reconstructed and meshed using the Rhinoceros v. 4.0 Evaluation software
(McNeel& Associates, Indianapolis, IN). Pulmonary veins are located at the back of
the atrium, two on each side at different heights. The appendage model used in this
has been modelled based on the data acquired from Ernst et al. with three lobes [
Characterizing left atrial appendage functions in sinus rhythm and atrial fibrillation
using computational models.
]. Blood was modelled as a non-Newtonian, viscous and incompressible fluid and represented
using the Navier-Stokes and continuity equation. Simulations were conducted using
the commercial software ANSYS FLUENT 14.0 (Ansys, Inc., Canonsburg, PA) and flows
have been analysed in diastole.