Hy yp pe er rt te en ns siio on n o on n T Tr ra an ns st th ho or ra ac ciic c E

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ISSN 1975-4612 Copyright ⓒ 2009 Korean Society of Echocardiography www.kse-jcu.org

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Innttrroodduuccttiioonn

Inferior sinus venosus type atrial septal defect (ASD) is rare and difficult to depict by transthoracic echocardiography (TTE) because of its infero-posterior location of the fossa ovalis.¹⁾²⁾So, this defect is frequently missed with conventional TTE views. We report a case of 19-year-old man with inferior sinus venous type ASD from the clue only from slight dias- tolic flattening of interventricular septum and mild pulmonary hypertension (PH).

C Caassee

A 19-year-old man without any specific past medical history came to the clinic, complaining of dyspnea on exertion for 4 years. He visited several hospitals before, but they couldn’t find out the cause of his symptoms. His symptom has been aggravating for the recent 3 months. An electrocardiogram showed normal sinus rhythm and QRS axis.

TTE showed no specific findings except mildly dilated right

atrium and ventricle and slight diastolic flattening of interven- tricular septum (Fig. 1). However, pulmonary arterial systolic pressure (PAsP) estimated from tricuspid regurgitation velocity (TRV) was normal (Fig. 2A). However mean pulmonary arterial pressure (mPAP) by simplified Mahan’s equation (mPAP=80-[RVOT AT 0.5]) calculating from acceleration time (AT) of right ventricular outflow tract (RVOT) was signi- ficantly increased to 35.6 mmHg (Fig. 2B).

Although mPAP showed mild PH, we recommended the right heart catheterization to determine the cause of symptom.

It demonstrated significant oxygen step-up between superior vena cava and inferior vena cava (oxygen saturation of superior vena cava; 73.2%, inferior vena cava; 89.7% and main pul- monary artery; 84.9%), increased pulmonary blood flow (Qp/Qs=1.8) and increased mPAP (26 mmHg). To find out the site of the shunt, we performed the transesophageal echo- cardiography (Fig. 3). It confirmed an inferior sinus venosus type ASD. ASD patch closure operation was performed for

Received: November 10, 2008 Accepted: February 5, 2009

Address for Correspondence: Wook-Jin Chung, Division of Cardiology, Department of Internal Medicine, Gachon University Gil Hospital, 1198 Guwol-dong, Namdong-gu, Incheon 405-760, Korea Tel: +82-32-460-8305 (Office), +82-32-460-3845 (Lab.), Fax: +82-32-460-8305, E-mail: [email protected]

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Division of Cardiology, Department of Internal Medicine, Gachon University Gil Hospital, Incheon, Korea C

CAASSEE RREEPPOORRTT J Cardiovasc Ultrasound 2009;17(1):25-27

Inferior sinus venosus type atrial septal defect (ASD) is a rare congenital cardiac deformity that occurs between the inferior vena cava and right atrium. Inferior sinus venosus defect is difficult to diagnose through transthoracic echocardiography because of its location which is infero-posterior to the fossa ovalis. Increasing pulmonary arterial pressure and pulmonary vascular resistance in patients with sinus venosus defect usually occur earlier than other types of ASD. We report a case of 19- year-old man who presented exertional dyspnea due to inferior sinus venous type ASD with mild pulmonary hypertension. In this case, we found clues from slight diastolic flattening of interventricular septum and shortened acceleration time of right ventricular outflow tract on initial transthoracic echocardiography, leading right heart catheterization and transesophageal echocardiography to reveal this rare type of ASD.

K

KEEYY WWOORRDDSS:Echocardiography·Atrial septal defect·Pulmonary hypertension.

Journal of Cardiovascular Ultrasound 17｜March 2009

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symptomatic hemodynamically significant left to right shunt (Fig. 4). The patient tolerated the operation and had an uneventful recovery.

D

Diissccuussssiioonn

Generally, sinus venosus type ASD is a rare cardiac abnor- mality in adults.¹⁾In General, the patient may remain asymp- tomatic and undiagnosed until the fourth decade of life when clinical signs and symtoms of pulmonary hypertension may develop. And pulmonary hypertension and increased pulm- onary vascular resistance occur at an earlier age in patients with a sinus venosus defect than other types of ASD and are clearly related to NYHA functional class.³⁾And these defects are frequently missed, and too difficult to visualize with conventional two-dimentional echocardiography views.²⁾⁴⁾ Although not taking in this case, agitated saline contrast occasionally maybe helpful to detect left to right shunt even in TTE.⁵⁾

TRV is usually the primary method for determining actual pulmonary pressure. However, TRV usually varies with respi- ration and was occasionally confused with high velocities B

A

B A

Fig. 2. Doppler findings. A: PAsP from TRV was within normal range. B: RVOT AT was 88.7 msec and calculated mPAP from the simplified Mahan’s equation (mPAP= 80-[RVOT AT×0.5]) was 35.6 mmHg (B). PAsP: pulmonary arterial systolic pressure, TRV: tricuspid regurgitation velocity, RVOT:

right ventricular outflow tract, AT: acceleration time, mPAP: mean pulmonary arterial pressure.

Fig. 3. Transesophageal echocardiography. Color Doppler imaging showed a defect at the extremely posterior portion of interatrial septum with left to right shunt flow.

Fig. 1. 2D views of transthoracic echocardiography. A: Parasternal short axis view at mid-LV level showed slight diastolic flattening of interventricular septum (arrows). B: Apical 4 chamber view showed mildly dilated right ventricle and atrium. LV: left ventricle.

Inferior Sinus Venosus Type ASD with PH｜Hyon Joung Cho, et al.

27 from aortic stenosis or mitral regurgitation. Although slight

diastolic flattening of interventricular septum was observed at two dimensional view, TRV showed within normal range in this case. Because TRV has many caveats like this case, we should evaluate alternative methods such as simplified Mahan’s equation in the case of clinically suspected PH.

Nonetheless, RVOT AT using simplified Mahan’s equation is not perfect and can be dependant on cardiac output and heart rate. Disappointingly, this case showed such discre- pancy (about 9.6 mmHg) between mPAP from simplified Mahan’s equation and mPAP through right heart catheteri- zation. So, right heart catheterization would be often required to confirm the presence of PH, establish the specific diagnosis, and determine the severity of PH.

Actually our patient had taken a long time to diagnosis. In this case, we found the clue only from slightly diastolic flattening of IVS because mildly dilated right ventricle and atrium are usually common findings in the pediatric and teen ages. Therefore, when encountering a patient with

unexplained dyspnea on exertion, physicians and sonogra- phers should have a clinical suspicion of PH and should not overlook a subtle clue which may lead to find an critical diagnosis for the patient.

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Reeffeerreenncceess

1. Arnheid KS, Andre L, Rene P, Peter B. Inferior sinus venosus defect associated with incomplete cor triatriatum dexter and patent foramen ovale.

Eur J Echocardiogr 2006;7:239-42.

2. Coon PD, Lang RM. Improved visualization of sinus venosus atrial septal defects in adults from the transthoracic approach. J Am Soc Echocardiogr 2006;19:1072.

3. Vogel M, Berger F, Kramer A, Alexi V, Lange PE. Incidence of secondary pulmonary hypertension in adults with atrial septal or sinus venosus defects.

Heart 1999;82:30-3.

4. Pascoe RD, Oh JK, Warnes CA, Danielson GK, Tajik AJ, Seward JB.

Diagnosis of sinus veosus atrial septal defect with transesophageal echocardiography. Circulation 1996;4:1049-55.

5. Oh KJ, Chung WJ, Shin MS, Han MY, Kang WC, Choi KL, Yang PS, Kim SY, Ahn TH, Shin EK. Unroofed coronary sinus associated with persistent left superior vena cava;detection by agitated saline contrast echocardiography. J Kor Soc Echocardiogr 2004;12:49-53.

Fig. 4. Patch repair of inferior sinus venosus type atrial septal defect (ASD) with autopericardium. The defect was located in inferior vena cava area and size was 1.5 cm. CS: coronary sinus, IVC: inferior vena cava.

Fossa ovalis

IVC CS

ASD: sinus venosus type, IVC area ASD GA-fixed autopericardial patch closure