Diagnostic and Interventional Imaging (2015) 96, 891—899

PICTORIAL REVIEW /Cardiovascular imaging

MDCT of

∗

D. Yasunaga , M. Hamon

Service de radiologie, pôle d’imagerie, CHU de Caen, avenue de la Côte-de-Nacre, 14033

Caen Cedex 9, France

KEYWORDS Abstract ECG-gated cardiac multidetector row computed tomography (MDCT) allows precise

Cardiac CT; analysis of the interatrial septum (IAS). This pictorial review provides a detailed description of

Interatrial septum; the normal anatomy, variants and abnormalities of the IAS such as patent , con-

Patent foramen genital abnormalities such as atrial septal defects as well as tumors and tumoral-like processes

ovale; that develop on the IAS.

Secundum ASD

© 2015 Published by Elsevier Masson SAS on behalf of the Éditions françaises de radiologie.

Introduction

Major technical advances in computed tomography (CT) in recent years have made it pos-

sible to use multidetector row CT (MDCT) in the field of cardiac imaging. Besides coronary

arteries, ECG-gated cardiac MDCT provides high-resolution images of all cardiac structures.

It is therefore important for radiologists to understand and be able to analyze the normal

anatomical structures, variants and diseases of these different structures.

This article provides an analysis of the interatrial septum (IAS) based on a pictorial

review. After a short embryological and anatomical description, we will illustrate the nor-

mal anatomy and variants of the IAS, anomalies such as patent foramen ovale (PFO),

congenital diseases such as atrial septal defects (ASD) as well as tumors and tumoral-like

processes that develop on the IAS.

Abbreviations: ASA, atrial septal aneurysm; ASD, ; ECG, electrocardiogram; IAS, interatrial septum; IVC, inferior

vena cava; IVS, ; LV, left ; M, myxoma; PFO, patent foramen ovale; RSPV, right superior pulmonary vein; RV,

right ventricle; SVC, superior vena cava; MIP, maximal intensity projection; TEE, transesophageal echocardiography; TV, . ∗

Corresponding author.

E-mail address: [email protected] (D. Yasunaga).

http://dx.doi.org/10.1016/j.diii.2015.02.011

2211-5684/© 2015 Published by Elsevier Masson SAS on behalf of the Éditions françaises de radiologie.

892 D. Yasunaga, M. Hamon

coughing, or a physical effort can create a right-to-left

Embryological and anatomical description

shunt: a paradoxical embolism may occur in this situation.

The IAS is composed of two septa: the and The prevalence of PFO varies depending on the imaging

the . modality and the population studied. In an autopsy-based

The septum primum, which is the thin wall of the IAS, series, the estimated prevalence was between 25% and 30%

develops first. Then, the septum secundum, which is com- in the general population [1]. It is observed in approximately

posed of muscular tissue, develops to the right of the septum 15% of patients with bubble saline contrast transthoracic

primum, by forming a tunnel between the two atria, called echocardiography and in 25% with transesophageal echocar-

the . The fossa ovalis includes the area that is diography (TEE) [2]. The presence of PFO is strongly

delimited by the septum secundum and covered by the sep- associated with neurological events such as cryptogenic

tum primum. ischemia stroke in young patients. In this population, the

During intrauterine life, these two walls are separate presence of a PFO is identified in approximately 40% of

and occurs through this tunnel. This physi- patients by TEE. In migraine patients in the MIST 1 study,

ological interatrial communication short circuits pulmonary nearly 38% of the patients were shown to have a PFO on

circulation and allows the flow of highly oxygenated blood contrast-enhanced echocardiography.

from the via the inferior vena cava towards Although TEE is the gold standard for the assessment

the left . of PFO, it is an invasive technique that is not always well

In the first months of life, the septa primum and secun- tolerated, requiring sedation that can make it difficult to

dum fuse in response to increased left atrial pressure, thus perform a valsalva maneuver. ECG-gated cardiac MDCT, with

creating a hermetically sealed wall between the two atria in its excellent spatial and temporal resolution, provides a pre-

70 to 75% of patients. However, in 25 to 30% of the general cise anatomical analysis of the IAS. In different studies,

population fusion of the septa does not occur or is incom- evaluating the IAS by MDCT, the following anatomic variants

plete, resulting in patent foramen ovale (PFO) (Fig. 1) [1]. of IAS were described (Fig. 2) [2—5]:

•

type 1: an IAS with no visible channel: no visible septal flap;

•

type 2: a closed channel;

Interatrial septum: anatomy and variants •

type 3: an open channel with no visible jet flow of contrast

(channel-like, PFO, ASA) material between the two atria;

•

type 4: an open channel with a visible jet flow of contrast

The development of ECG-gated cardiac MDCT has made it

material between the atria.

possible to identify several morphological variants of the

IAS on imaging:

• The three latter types correspond to the classification

a completely closed IAS with no residual flap. Only the

‘‘channel-like’’.

location of the fossa ovalis can be identified. This cor-

In a study of 152 patients comparing cardiac MDCT to TEE

responds to complete fusion of the septa primum and

(the gold standard for the detection of PFO), Kim et al. con-

secundum;

• cluded that the diagnosis of PFO by cardiac MDCT is strongly

a so-called ‘‘channel-like’’ variant, which is seen as a

suggested in the presence of type 4 IAS (open channel with

channel in the IAS. This ‘‘channel-like’’ feature in the

a jet flow of contrast material towards the right atrium,

IAS is a sign of incomplete fusion of the septa primum

confirming the presence of a left-to-right shunt) [5]. On the

and secundum, so that the septum primum is visible on

other hand, a closed or opened channel with no visible jet

the left side of the IAS. On MDCT this ‘‘channel-like’’

flow (types 2 and 3) does not reliably confirm the presence

element appears tubular shaped in the IAS. This channel-

of PFO. According to Saremi et al., a short channel and the

like IAS is a frequent anatomical variant in adults, which

presence of an atrial septal aneurysm (ASA) are frequently

is usually asymptomatic, and only associated with con-

associated with the presence of a shunt (Fig. 3) [3].

firmed PFO in certain cases (cf. infra). The frequency of

Compared to TEE, cardiac MDCT only provides anatomi-

this ‘‘channel-like’’ variant ranges in the literature from

cal information obtained during a single breathhold, with no

15 to 38% [2,3].

provocative test possible. This explains the mediocre sen-

sitivity of cardiac MDCT for the diagnosis of PFO. While a

Patent foramen ovale left-to-right shunt through a ‘‘channel-like’’ IAS is specific

for PFO on cardiac MDCT, a channel-like IAS alone can be

PFO is a short permeable interatrial tunnel that is caused observed in patients without PFO. The presence of a shunt

by incomplete fusion of the septum primum and the septum associated with PFO depends not only on interatrial pressure

secundum, creating a double wall. but also on the anatomical characteristics of the PFO, such

PFO needs to be distinguished from fossa ovalis defect as the size of the entry zone into the right atrium and the

(secundum ASD) by the completeness of the septum pri- length of the channel. A left-to-right shunt is more frequent

mum that is able to overlap the muscular rim of the septum when the free flap of the PFO (corresponding to the free

secundum under normal circumstances. rim of the septum primum) is short [3]. Moreover, a short

PFO can result in an intermittent bidirectional shunt channel and an ASA are frequently associated in patients

between the two atria based on the respiratory cycle. A left- presenting with a PFO with a left-to-right shunt.

to-right shunt is the most frequent. However, any temporary Despite the insufficient diagnostic sensitivity for PFO,

increase in right atrial pressure, such as a valsalva maneuver, cardiac MDCT can nevertheless provide precise anatomical

MDCT of interatrial septum 893

Figure 1. Normal interatrial septum on the left and patent foramen ovale on the right.

information that can be useful for planning procedures and is defined by dyspnea with a decrease in the PaO2

such as percutaneous PFO closure, which is being exten- caused by orthostatism posture and improved in supine posi-

sively studied at present and whose indications are under tion. There are no published guidelines to date on the

evaluation. Although most patients presenting with PFO indications for percutaneous PFO closure. There are several

are asymptomatic, there is a strong association between ongoing randomized multicenter studies evaluating the effi-

the presence of PFO and certain clinical events: cryp- cacy of PFO closure for the secondary prevention of stroke

togenic ischemic stroke in young patients, migraine with in young patients who have presented a cryptogenic stroke

aura, decompression sickness and platypnea-orthodeoxia (CLOSURE, RESPECT, CLOSE) and for the treatment of aura

syndrome. The latter is a rare cause of postural hypoxemia migraine (MIST).

Figure 2. Different appearance of interatrial septum (IAS) on a short axis view through the atria: a: normal IAS without channel (black

arrow); b: ‘‘channel-like’’ appearance with closed flap (black arrow); c: ‘‘channel-like’’ appearance with open flap (black arrow); d: patent

foramen ovale with channel-like appearance (open flap) and left-right shunt (black arrow).

894 D. Yasunaga, M. Hamon

congenital defect in adults and has been found to be

more frequent in women [6].

The classification of interatrial defects is based on an

understanding of the development of IAS as well as the sur-

rounding systemic and pulmonary vascular system. There are

three main types of ASD, including ostium secundum, ostium

primum and . Coronary sinus ASD is very rare.

Secundum ASD corresponds to a defect within septum pri-

mum at the fossa ovalis (Fig. 5). It is the most common ASD

and account for approximately 70% of all ASD [1]. The size

of this ASD can vary from several millimeters to 2—3 cm.

Large defects are sometimes associated with a complete

absence of a septum primum. Because of physiological fetal

circulation, a prenatal diagnosis is extremely difficult.

Primum ASD corresponds to a defect in the anterior and

inferior part of the IAS, adjacent to the atrioventricular

canal. They account for approximately 20% of ASD, and are

frequently associated with interventricular defects in the

anterior leaflet of the [1]. They can be diag-

nosed in the prenatal assessment.

Sinus venosus defect account for approximately 10% of

Figure 3. Short axis view through the atria: patent foramen ovale

ASD [1]. This ASD is located outside the limits of the fossa

with left-right shunt (white arrow), and atrial septal aneurysm

ovalis in the wall that normally separates the left atrial

(black arrow).

septum and the superior or inferior vena cava. Most sinus

venosus ASD (nearly 90%) are in the upper atrial septum and

Atrial septal aneurysm (ASA)

are associated in 85% of the cases with anomalous partial

pulmonary venous drainage, usually of the right upper pul-

ASA is defined as abnormal mobility of the fossa ovalis mem-

monary vein into the SVC, as a result of a defect in the tissue

brane (excursion of more than 10 mm), towards the left

separating these two veins (Fig. 6).

and/or the right, with an aneurysmal bulging of all or part

Coronary sinus defect is a rare congenital disease that

of the interatrial wall. It can be diagnosed during routine

is the least frequent ASD. It is characterized by a partial

echocardiography, cardiac MDCT or MRI. Its prevalence in

or total absence of the wall separating the upper coronary

autopsy-based series is approximately 1%.

sinus from the left atrium resulting in shunting through the

ASA can be isolated or associated with other anomalies

defect. In its purest form, it is associated with a persis-

such as PFO, an atrial septal defect or a sinus venosus septal

tent left superior vena cava, which is connected to the left

defect. An ASA is found in approximately 4% of PFO (Fig. 4). atrium.

Atrial septal defects Physiopathology

Description, nomenclature and classification Although most patients with an ASD have a left-to-right

shunt, certain ASD may be associated with a right-to-left

Atrial septal defects (ASD) represent the third most frequent shunt. Indeed, the direction and force of the blood flow

form of congenital heart disease (after ventricular septal through the ASD are determined by the size of the defect

defects and patent ). It is the most frequent and atrial pressures, which are dependent upon left and

Figure 4. Atrial septal aneurysm (with arrow) with excursion into right atrium: a: four-chamber view; b: short axis view through the atria.

MDCT of interatrial septum 895

Figure 5. Secundum atrial septal defects (arrowheads) with rim measurements. Ao: ; A: aortic rim; AV: atrioventricular valve rim;

SVC: superior vena cava rim; IVC: inferior vena cava rim; P: posterior rim; S: superior rim: a: four-chamber views; b: aortic short axis

view; c: bi-caval view; d: axial view. Right heart failure signs (black arrow): right ventricle dilatation, contrast agent reflux in IVC, and in

sus-hepatic veins.

right ventricular compliance. The size of the defect and drainage, which is very frequent, creates an additional left-

ventricular compliances can change over time. If LV compli- to-right shunt and patients have a three fold greater risk of

ance decreases, the left-to-right shunt increases. Conditions developing than those with secun-

leading to a decrease in RV compliance, such as pulmonary dum ASD.

hypertension, have the opposite effect: reduction of the

left-to-right shunt until a right-to-left shunt develops. An old

Diagnostic imaging

ASD can cause right ventricular dilatation, right ventricular

dysfunction, hypertrophy, then myocardial fibrosis. The pul-

Although echocardiography is still the gold standard imag-

monary vascular bed is remodeled due to the proliferation

ing technique, according to the technical progress made in

of myointimal cells and an increase in collagen leading to

cardiac MDCT, this modality now provides a precise morpho-

narrowing of arterioles and pulmonary hypertension.

logical assessment of ASD, as well as useful complementary

information for the detection of cardiac anomalies (coro-

Clinical presentation nary arteries, valves, , cardiac chambers) and

associated extracardiac anomalies, for the evaluation of

Most patients with ASD are asymptomatic during childhood. pulmonary vascularization, and for the pretherapeutic work-

Patients in their twenties can remain asymptomatic or have up. MDCT is ideally performed to limit the radiation dose

mild symptoms such as effort dyspnea or palpitations: exer- given to the patient [7]. Technically the administration of

cise intolerance is the most common initial symptom. When contrast material can be biphasic (administration of a bolus

patients develop symptoms, they may include supraventric- of iodinated contrast material followed by a bolus of saline

ular arrhythmias (fibrillation or flutter), right heart failure, solution) or triphasic (iodinated contrast material, a mixture

stroke induced by paradoxical embolism and pulmonary of contrast material and saline, then pure saline). A biphasic

hypertension. protocol has the advantage of providing good opacification

Small ostium secundum ASD, less than 10 mm in diame- of the chambers of the left heart and better identification

ter, usually does not have any hemodynamic consequences of shunts, while a triphasic protocol provides better visu-

and remain asymptomatic. Primum ASD tends to be larger, alization of the chambers of the right heart. Cardiac MDCT

and patients usually develop symptoms earlier than with is an important diagnostic tool for sinus venosus ASD. The

other types. In sinus venosus ASD, partial pulmonary venous posterior location of the defects and frequently associated

896 D. Yasunaga, M. Hamon

Figure 6. Sinus venosus atrial septal defects between left atrium and superior vena cava (white arrowheads) with anomalous connection

of the right pulmonary superior vein to the superior vena cava: a: axial view at left atrium; b: axial view through right ;

c: oblique sagittal view; d: oblique coronal view.

pulmonary venous drainage anomalies make it difficult to Role of cardiac MDCT in the choice of

obtain an optimal assessment of this type of ASD by echocar-

procedure and for planning percutaneous

diography.

closure of secundum ASD

MRI can be helpful for the evaluation of the right heart,

for example to calculate volumes and right ventricular func-

tion and to evaluate the relationship of pulmonary flow to Transcatheter ASD closure is used as a safe and effec-

systemic flow in a phase-contrast sequence. MR angiography tive alternative to open surgical repair (Fig. 7). However,

can also be used to analyze pulmonary venous drainage into despite the operator’s experience, implantation failures can

sinus venosus ASD. occur, and major complications occur in less than 1% of

patients (cardiac tamponade complicating cardiac perfora-

Role of imaging for treatment strategy tion, migration of the device) [1,6,8].

For a successful procedure and an optimal choice of the

Closure of ASD is indicated, with or without symptoms, in closure device, it is important for the interventional cardi-

the presence of a large shunt causing right heart dilatation ologist to have a good knowledge of the morphology and the

(class I, level of evidence B). The other indications are sus- largest diameter of the ASD, as well as precise information

pected paradoxical embolism in the absence of any other about the different rims and adjacent structures of the ASD.

cause of stroke (class IIa, level of evidence C), and the pres- Adequate-sized rims allow complete closure of the ASD and

ence of a confirmed platypnea-orthodeoxia syndrome [1]. reduce the risk of device migration.

If pulmonary hypertension is too severe, this constitutes Contraindications to transcatheter closure include ASD

contraindication for closure of ASD [1]. larger than 36—40 mm in maximal diameter, proximity of the

Closure is not necessary with small interatrial defects ASD to the atrioventricular valve, the vena cavas or the coro-

with no signs of right ventricular volume overload and no nary sinus, and atrial tissue rims around the defect that are

clinical symptoms, but the patient should be monitored for inadequate for good device deployment (rims < 5 mm) [1,6].

possible enlargement of the shunt over time. Amin has proposed an ultrasound classification for the

Although surgical treatment is recommended in primum pretherapeutic assessment of ASD rims based on adjacent

ASD, sinus venosus defect and coronary sinus defect, a trans- structures [8] (Fig. 8): the aortic rim adjacent to the aortic

catheter approach is preferable in patients presenting with valve; the superior vena cava rim adjacent to the superior

an ‘‘anatomically eligible’’ secundum ASD [1,6]. vena cava; the superior rim between the superior vena cava

MDCT of interatrial septum 897

Figure 7. Transcatheter closure of a secundum atrial septal defects: amplatzer atrial septal occluder device (white arrows): a: axial view;

b: short axis view through the atria; c: maximal intensity projection oblique coronal reformation.

and the aortic rims, the posterior rim opposite to the aortic pretherapeutic work-up, for patient selection and for the

rim between superior and inferior vena cavas rims; the infe- optimal size of the septal occlusion device for transcatheter

rior vena cava rim adjacent to the inferior vena cava and the closure.

atrioventricular valve rim adjacent to the atrioventricular Thus the following measurements obtained by car-

valve. diac MDCT and adapted from the Amin classification, are

Although TEE is the first choice imaging modality, it can obtained on the three planes (Fig. 5) [9]:

•

have technical limitations for the visualization of the entire ‘‘bi-caval’’ view for the superior vena and inferior vena

ASD, as well as for the evaluation of the largest diameter of cava rims. From an axial image at the level of both

the ASD and its rims. According to precise measurement of atrioventricular valves this plane is obtained from a line

the ASD and its rims with views that are similar to TEE, car- perpendicular to the IAS;

•

diac MDCT can provide complementary information for the ‘‘aortic short axis view’’ for the posterior and aortic rims.

From a coronal image at the level of the , this

plane is obtained from a parallel line to the aortic valve;

•

‘‘four-chamber’’ view for the superior and atrioventricu-

lar valve rims.

The cardiac MDCT report should mention the following

elements from each of the abovementioned views: the total

length of the IAS, the maximum diameter of the ASD and the

shortest length of the rims [9].

In addition cardiac MDCT makes it possible to detect

numerous defects and any associated cardiac or extracar-

diac anomalies.

Tumors and pseudotumors of the

interatrial septum

Lipomatous hypertrophy

Lipomatous hypertrophy is a benign condition character-

ized by fat accumulation in the IAS. It usually develops in

elderly, obese patients. It is usually asymptomatic and may

be associated with supraventricular arrhythmia. Although

the prevalence of lipomatous hypertrophy is unknown, it

is estimated to be 1% in autopsy series, reaching 8% with

transthoracic ultrasound and was evaluated to be approxi-

mately 2% in a large MDCT study [10].

Lipomatous hypertrophy is usually diagnosed incidentally.

MDCT reveals a homogenous, unenhanced mass of fat atten-

Figure 8. Diagram of atrial septal defects rims. S: superior rim;

uation with sharp margins that are at least 20 mm thick

AO: aortic rim; AV: atrioventricular rim; IC: inferior vena cava rim;

P: posterior rim; SC: superior vena cava rim. [10]. The fossa ovalis is always spared creating a ‘‘dumbell

Adapted from Amin.

shape’’. These characteristic morphological criteria strongly

898 D. Yasunaga, M. Hamon

suggest the diagnosis of lipomatous hypertrophy and help On cardiac MDCT, a myxoma appears as a hypodense het-

differentiate this benign disorder from other cardiac tumors, erogeneous lobulated round or oval mass that may develop

preventing unnecessary biopsy and histological confirmation in any chamber, and that is enhanced following administra-

(Fig. 9). tion of contrast material. The pedicle attaching the tumor

to the IAS can be visualized (Fig. 10).

Atrial myxoma Thrombus

Myxomas are the most frequent primary tumors of the heart Thrombus is the most frequent pseudotumoral intracardiac

(approximately 50% of primary cardiac tumors) [11]. mass.

They are usually isolated and benign. They are character- Intracardiac thrombi generally develop within specific

ized by a lobulated, polypoid mass that most often develops contexts: most frequently left intraventricular thrombi

on the IAS in the left atrium (75%), but can develop in any develop due to sequella from myocardial infarction or left

cardiac chamber (15% in the right atrium). They can be ses- intra-atrial thrombi from atrial fibrillation [11]. Thrombi

sile but are more frequently pedunculated, which explains located near the IAS in the right atrium usually occur in the

the mobile features of certain myxomas. The largest tumors presence of a long-term central venous catheter with the

can prolapse through the atrioventricular valve [mitral valve development of a thrombus at the end of the line. Some-

if located in the left atrium or tricuspid in the right atrium times thrombi can be observed extending from the inferior

(Fig. 10)], and cause hemodynamic disorders [11]. vena cava (Fig. 11).

Symptoms depend on the size, the location and the mobil- A mixture of non-opacified blood from the inferior vena

ity of the tumor and include signs of heart failure, embolic cava, and enhanced blood from the superior vena cava can

complications and arrhythmia. Because of the non-specific result in a false positive for thrombus. A later acquisition

clinical presentation of this entity, imaging plays an impor- showing homogenous atrial opacification excludes the pres-

tant diagnostic role. ence of thrombus.

Figure 9. Lipomatous hypertrophy of the interatrial septum (white arrows in a and b) sparing the fossa ovalis (black arrows), resulting

in a ‘‘dumbell shape’’: a: axial view; b: oblique sagittal view; c: oblique axial view, with fat accumulation along the coronary sinus (white

arrow) resulting in ‘‘finger-like’’ appearance.

Figure 10. Myxoma (M) in right atria, with pedunculated attachment to interatrial septum (black arrow), mobile, with diastolic prolapse

of the myxoma in the right ventricle through the tricuspid valve plane: a: systolic four-chamber view; b: diastolic four-chamber view.

MDCT of interatrial septum 899

Figure 11. Renal tumour (arrowhead) with thrombus extending from the inferior vena cava (black arrow) to the right atrium and comes

into contact with interatrial septum (white arrow): a: axial view; b: coronal view.

It is sometimes difficult to differentiate between myxoma undergoing routine ‘‘coronary’’ 64-multi-detector cardiac

and thrombi. They can be differentiated by their size, their computed tomography. Ulster Med J 2011;80(2):72—5.

[3] Saremi F, Channual S, Raney A, Gurudevan SV, Narula J, Fowler

origin, their shape and their mobility. Thrombi are smaller

S, et al. Imaging of patent foramen ovale with 64-section mul-

and less mobile than myxomas [11]. They have low CT atten-

tidetector CT. Radiology 2008;249(2):483—92.

uation values (approximately 60 HU), are non-infiltrating

[4] Williamson EE, Kirsch J, Araoz PA, Edmister WB, Borgeson DD,

and do not enhance following contrast material administra-

Glockner JF, et al. ECG-gated cardiac CT angiography using

tion.

64-MDCT for detection of patent foramen ovale. AJR Am J

Roentgenol 2008;190(4):929—33.

[5] Kim YJ, Hur J, Shim C-Y, Lee H-J, Ha J-W, Choe KO, et al.

Conclusion Patent foramen ovale: diagnosis with multidetector CT —

comparison with transesophageal echocardiography. Radiology

ECG-gated cardiac MDCT provides a detailed analysis of the 2009;250(1):61—7.

IAS. Knowledge of the normal anatomy, variants, and dis- [6] Webb G, Gatzoulis MA. Atrial septal defects in the adult:

recent progress and overview. Circulation 2006;114(15):

eases of the IAS is important for radiologists because of

1645—53.

the clinical, interventional and surgical implication of these

[7] Greffier J, Fernandez A, Macri F, Freitag C, Metge L, Beregi

elements. With the development of transcatheter ASD clo-

JP. Which dose for what image? Iterative reconstruction for CT

sure techniques, cardiac MDCT is probably going to play an

scan. Diagn Interv Imaging 2013;94(11):1117—21.

increasingly important role in the future for the pre- and

[8] Amin Z. Transcatheter closure of secundum atrial septal

post-therapeutic evaluation of these procedures.

defects. Catheter Cardiovasc Interv 2006;68(5):778—87.

[9] Espejo S, Ysamat R, Cajal B, Pan M, Romero M, Garcia D, et al.

Multidetecor computed tomography in the evaluation of atrial

Disclosure of interest septal defects; 2010. ESR.org [en ligne]. http://posterng.

netkey.at/esr/viewing/index.php?module=viewing poster&

The authors declare that they have no conflicts of interest task=&pi=100501&searchkey=9eb562dca9340397e5676855a3a

00bec. [accessed May 2014].

concerning this article.

[10] Heyer CM, Kagel T, Lemburg SP, Bauer TT, Nicolas V. Lipoma-

tous hypertrophy of the interatrial septum: a prospective study

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