Cross section of the right atrium as seen from the right side. At the top the superior vena cava (VCS),
at the bottom the inferior vena cava (VCI), to the right the tricuspid valve (TV).
1: Patent foramen ovale
2: ASD II = ostium secundum atrial septal defect
3: ASD I = ostium primum atrial septal defect
4: Sinus venosus defect
5: Anomalous drainage of one or more pulmonary veins
6: Sinus coronarius defect
An interatrial shunt may be suspected in the presence of following findings in transthoracic echocardiography (TTE):
dilated right ventricle with preserved systolic function, dilated right atrium, as well as increased velocities
over the pulmonary valve.
To define localisation and morphology, as well as depiction of the shunt, a multiplane transesophageal echocardiography
(TEE) should be performed.
Non-invasive assessment of shunt magnitude (Qp:Qs) can be made with the following formula:
(CSARVOT x VTIRVOT)/(CSALVOT x VTILVOT).
Cross sectional area (CSA)
calculated from the diameter of the right (RVOT) and left ventricular outflow tract (LVOT) measured in the
bidimensional mode and velocity time integral (VTI) with PW-Doppler at the same place during passive end expiration.
Next 4 animations apply to an ostium secundum atrial septal defect (ASD II).
TEE examination at 0° shows a large ASD II in the upper part of the fossa ovalis.
ASD II at 90°.
demonstration of a large left-to-right shunt with color Doppler.
negative contrast effect showed with an non-transpul- monary ultrasound contrast agent, with partial
crossing from RA to LA.
Next 7 animations apply to ano- ther ASD II case.
Four chamber view. The RV is dilated with not severely decreased systolic function. The RA is severely dilated. An atrial shunt
is suspected. A TEE exami- nation should follow.
Right: short axis view shows a dilated RV.
TEE view at 100° shows an ASD II at the superior portion of the foramen ovale.
Shunt depiction with color Doppler. The Nyquist limit lies at 60-70 cm/s, slow
velocities speak for a moderate to severe shunt.
ASD II depiction with "real- time 3D echocardiogra- phy" (RT3D-TEE).
The ASD II as seen from the LA (arrow), superior vena cava (VCS) confluence and right atrial appendage (RAA)
are labeled here.
ASD II as seen from the right atrium (RA). Depiction with RT3D-TEE uses colors to give the impression of deepness: light blue lies
on a deeper level than light brown.
Shunt depiction with color 3D echocardiography, as seen from the RA.
Next 4 animations apply to diffe- rent cases of patent foramen ovale (PFO) and/or atrial septal aneurysm (ASA).
several small left-to-right shunts depicted with color Doppler (PFO fenestrations).
ASA and PFO with massive right-to-left ultrasound contrast agent passage at the end of a Valsalva maneuver.
spontaneous right-to-left shunt can be depicted with color Doppler in cases of large PFO.
this can cause a reduction in oxygen saturation and dyspnea during changes in body position
here a case of a complete atrioventricular (AV) canal defect, with ASD I and a large superior located VSD.
Septal insertion of AV valves (mitral and tricuspid) lies at the same level.
a malformation of the AV valves, especially of the mitral valve (cleft) cannot be seen in this case.