European Journal of Echocardiography 2007 8(6):494-497; doi:10.1016/j.euje.2006.07.014
Copyright © 2007, The European Society of Cardiology
How to prevent echocardiographic misinterpretation of Gerbode type defect as pulmonary arterial hypertension
Faramarz Tehrania and
Mohammad-Reza Movahedb,*
aDepartment of Medicine, University of California, Irvine Medical Center, Orange, CA, USA
bSarver Heart Center, University of Arizona Medical Center, Department of Medicine, Section of Cardiology, 1501 North Campbell Avenue, Tucson, AZ 85724, USA
Received 16 May 2006; received in revised form 17 July 2006; accepted after revision 26 July 2006.
* Corresponding author. Tel.: +1 520 626 2000; fax: +1 949 400 0091. rmovahed{at}email.arizona.edu rmova{at}aol.com
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Abstract
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We present a rare case of left ventricular to right atrial communication,
a Gerbode type defect discovered in an adult female, originally
misinterpreted as pulmonary arterial hypertension. The case
report will be followed by the review of the literature and
a discussion about how to prevent echocardiographic misinterpretation
of this defect as pulmonary arterial hypertension using careful
echocardiographic examination.
Keywords: Gerbode type defect; Pulmonary hypertension; Echocardiography; Ventricular septal defect
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Case report
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A 49-year-old female presented with a one-year history of fatigue
and palpitations without any other cardiac symptoms. She was
told that she had a very small ventricular septal defect (VSD)
as a child. Her exercise nuclear test revealed normal perfusion.
She exercised over 10min on Bruce protocol reaching 134% of
her age-predicted exercise capacity. An echocardiogram was performed
which was interpreted as following: normal valves and cardiac
chambers except moderate tricuspid regurgitation with estimated
pulmonary arterial systolic pressure of 74mmHg. Her EKG and
pulmonary function tests were normal.
Due to relocation, the patient came to us for further evaluation. Physical exam was normal except 3/6 systolic murmur at the apex and the left sternal border. Her 24hours Holter monitor revealed no significant arrhythmias. Echocardiogram was repeated at our institution and reviewed in detail. She had normal valves and normal cardiac chambers. Continuous pulse Doppler study showed a mild-to-moderate tricuspid regurgitation with a high velocity jet of 4.95m/s (Figs. 1 and 2
). However, on closer inspection and careful review of her echocardiogram, we visualized a clear jet across a small defect between left ventricle and right atrium consistent with Gerbode type defect with a small VSD located at the same level. The continuous wave Doppler showed high velocity jet in the direction of Doppler probe as a jet summation of TR and Gerbode defect. The direction of the Doppler signal also leads to the true diagnosis (Figs. 1 and 3). Inferior cava vein was normal in size with inspiratory collapse consistent with normal right-sided pressures. Furthermore, the pulmonic diastolic regurgitation jet velocity was very low (less than 0.5m/s) consistent with normal pulmonic diastolic pressure (Fig. 4). Reviewing the outside report of her previous echocardiogram also revealed a low velocity pulmonary regurgitation jet.
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Figure 2 Continuous wave Doppler from Gerbode type defect mixed with tricuspid regurgitation jet revealing a high velocity jet simulating severe pulmonary arterial hypertension with estimated systolic pulmonary arterial pressure of 98mmHg.
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Figure 4 Arrow showing pulse wave Doppler of pulmonary valve regurgitation jet velocity that can be seen next to the measured systolic velocity in the diastole revealing a peak velocity of less than 0.5m/s consistent with normal pulmonary artery diastolic pressure.
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A right or left heart catheterization was not performed given
that the patient was asymptomatic and careful evaluation of
her echocardiographic examination did not point to pulmonary
arterial hypertension or significant left-to-right shunting.
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Discussion
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Gerbode defect is a rare form of VSD that allows for communication
between the left ventricle and the right atrium, originally
described in 1958 by Gerbode through surgical correction of
five observed cases.
1 Although the majority appears to attribute
the Gerbode defect to congenital origins,
2,3 there have been
publications in the past that have credited the defect's formation
secondary to bacterial endocarditis.
4,5
In a Gerbode defect the left ventricular outflow tract to right atrium communication allows for shunting of blood to the right atrium during systole. If this communication is large, it can lead to volume overload and chamber enlargement.6 Anatomically the defect is located in the membranous interventricular septum, either inferior or superior to the level of the tricuspid valve.3 The more common congenital form of the Gerbode defect is found inferior to the insertion of the tricuspid valve in the interventricular septum. These are usually accompanied with malformations of the tricuspid valve. The supravalvular form occurs between the right atrium and the left ventricle above the tricuspid valve insertion point.7,8 The supravalvular form of the Gerbode defect appears to have a greater correlation with infective endocarditis, as it is thought that the bacterial infection affects the subannular region causing rupture of a section of the high membranous septum and the creation of the shunt directly connecting the left ventricle to the right atrium.9
Our case is the first adult case report in that the Gerbode type defect was originally misdiagnosed as severe pulmonary arterial hypertension by the use of echocardiography. Our patient's first echocardiogram was misinterpreted as severe pulmonary hypertension by mistakenly interpreting the Gerbode defect jet as tricuspid regurgitation jet. In our case, the absence of other signs or symptoms of right ventricular overload and careful review of the jet direction and estimation of pulmonary arterial diastolic pressure using pulmonary regurgitation jet were able to unmask this mistake. Although cases of non-surgical diagnosis of Gerbode type defect with the use of echocardiography have been reported,10 it still remains a difficult task to detect such left ventricular to right atrial communications. Therefore, it is very important that careful attention should be given during the echocardiographic interpretation of patients with history of membranous ventricular septal defect in order to identify Gerbode type defect as a cause of high velocity jet in the right atrium simulating pulmonary arterial hypertension. The presence of normal diastolic pulmonary arterial pressure using pulmonic regurgitation jet is very useful to distinguish the true pulmonary arterial hypertension from high velocity jet in the right atrium caused by Gerbode type defect.
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References
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- Gerbode F., Hultgren H., Melrose D., Osborn J. Syndrome of left ventricular-right atrial shunt: successful surgical repair of defect in five cases, with observation of bradycardia on closure. Ann Surg (1958) 148(3):433–446.[Web of Science][Medline]
- Amplatz KMJ. Radiology of congenital heart disease [Book]; 1993. p. 258–90.
- Riemenschneider T.A., Moss A.J. Left ventricular–right atrial communication. Am J Cardiol (1967) 19(5):710–718.[CrossRef][Web of Science][Medline]
- Ono K., Kitamura N., Otaki M., Tamura H., Yamaguchi A., Miki T. Left ventricular–right atrial shunt due to infective endocarditis – report of a case. Nippon Kyobu Geka Gakkai Zasshi (1991) 39(9):1809–1812.[Medline]
- Battin M., Fong L.V., Monro J.L. Gerbode ventricular septal defect following endocarditis. Eur J Cardiothorac Surg (1991) 5(11):613–614.[Abstract]
- Wasserman S.M., Fann J.I., Atwood J.E., Burdon T.A., Fadel B.M. Acquired left ventricular–right atrial communication: Gerbode-type defect. Echocardiography (2002) 19(1):67–72.[CrossRef][Web of Science][Medline]
- Velebit V., Schoneberger A., Ciaroni S., Bloch A., Maurice J., Christenson J.T., et al. "Acquired" left ventricular-to-right atrial shunt (Gerbode defect) after bacterial endocarditis. Tex Heart Inst J (1995) 22(1):100–102.[Web of Science][Medline]
- Cantor S., Sanderson R., Cohn K. Left ventricular–right atrial shunt due to bacterial endocarditis. Chest (1971) 60(6):552–554.[CrossRef][Web of Science][Medline]
- Elian D., Di Segni E., Kaplinsky E., Mohr R., Vered Z. Acquired left ventricular–right atrial communication caused by infective endocarditis detected by transesophageal echocardiography: case report and review of the literature. J Am Soc Echocardiogr (1995) 8(1):108–110.[CrossRef][Medline]
- Shen W.K., Khandheria B.K. Transesophageal echocardiography: detection of an acquired left ventricular–right atrial shunt. J Am Soc Echocardiogr (1991) 4(2):199–202.[Medline]
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