Case Study

Giant right atrial diverticulum with thrombus formation

Asian Cardiovascular & Thoracic Annals 2015, Vol. 23(3) 314–316 ß The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492313504768 aan.sagepub.com

Yoshiyuki Sato1, Hirono Satokawa1, Akihiro Yamamoto1, Hitoshi Yokoyama1 and Kazuhira Maehara2

Abstract A 28-year-old man was referred to our hospital with a giant right atrial diverticulum. The mass of the right atrial diverticulum compressed the right atrium and right ventricle, and thrombus formation was suspected. The diverticulum was surgically excised and the patient remained asymptomatic a year later.

Keywords Atrial appendage, Diverticulum, Heart Aneurysm, Heart Atria, Thrombosis

Introduction Right atrial diverticulum (RAD) is a very rare cardiac anomaly with etiology reported to be congenital.1,2 RAD has been identified by terms such as right atrial aneurysm, diverticulum, or idiopathic dilatation.3 Some complications including arrhythmia, thrombosis, and rupture may occur. However, the incidence of RAD with thrombus formation is extremely rare. Here we describe the surgical treatment of a case of giant RAD with thrombus formation.

Case report A 28-year-old man was referred from another hospital because of cardiomegaly on a chest radiograph. There was no specific familial history of cardiac diseases. The findings on admission were height 169 cm, weight 69 kg, blood pressure 126/76 mm Hg, and pulse rate 72 beats min 1 with a regular rhythm. His cardiorespiratory examination was unremarkable. An electrocardiogram showed regular sinus rhythm. A posteroanterior chest radiograph revealed cardiomegaly with a cardiothoracic ratio of 70%, and the right 2nd and left 4th arches projected (Figure 1). Transthoracic echocardiography indicated a large cystic structure that communicated with the right atrium. The entire image of the mass could not be clearly examined. The right atrium and right ventricle were displaced posteriorly by the mass, and there was good left ventricular contraction (Figure 2).

Contrast-enhanced computed tomography demonstrated a large structure at the front of the right ventricle, which had a communication near to the right atrial appendage. There was a filling defect that was suspected to be due to an intracavity thrombus or trabeculation (Figure 3). Coronary angiography showed no stenosis and no anomaly. The patient remained generally well. However, we diagnosed a giant RAD. Surgical resection was planned due to compression of the right ventricle and right atrium and the risk of a thrombotic complication. After a median sternotomy, the diverticulum was visible and arose from the right atrial appendage to the upper part of the right atrial free wall (Figure 4). The diverticulum wall had rich fatty tissue and many creases. Cardiopulmonary bypass was established by cannulation of the ascending aorta and both venae cavae. There was a fresh adherent thrombus in the RAD. The RAD including the right atrial wall was removed. The defect in the right atrial 1 Department of Cardiovascular Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan 2 Department of Circulatory Internal Medicine, Shirakawa Kosei General Hospital, Fukushima, Japan

Corresponding author: Hirono Satokawa, MD, Department of Cardiovascular Surgery, Fukushima Medical University, School of Medicine, 1 Hikarigaoka, Fukushima 960-1295, Japan. Email: [email protected]

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Figure 1. Chest radiograph on admission.

Figure 3. Contrast-enhanced computed tomography. Upper: cross-sectional image. Lower: sagittal section demonstrating a right atrial diverticulum (*) with a filling defect (arrow).

wall was repaired using a patch of autologous pericardium. Pathological examination of the resected RAD showed extensive fatty infiltration among the cardiac muscle fibers, and there were parts in which most of the muscle fibers had disappeared. The patient’s postoperative course was uneventful. He regularly visited our outpatient clinic, and computed tomography at one year postoperatively revealed no recurrence of the RAD.

Discussion

Figure 2. Echocardiography findings. Upper: (long-axis view) arrow indicates the right atrial diverticulum. Lower: (short-axis view) the right ventricle (RV) is seen to be compressed. Ao: ascending aorta; LV: left ventricle; RA: right atrium.

RAD is very rare and almost always congenital in origin.1,4 Patients with RAD may present with atrial arrhythmia, or a large RAD may compress the heart. Therefore, the symptoms are shortness of breath, palpitations, easy fatigability, and right heart failure; however, many patients remain asymptomatic until late in life.2 Binder and colleagues2 classified congenital malformations of the right atrium into 3 categories: congenital enlargement of the right atrium, single diverticulum of the right atrium, and multiple diverticula of the right atrium. Kobza and colleagues5 emphasized that an aneurysm is defined as dilatation of the atrium involving all layers of the atrial wall, but diverticulum of the right atrium is usually described as a saccular structure that

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Figure 4. Operative findings. Upper left: the right atrial diverticulum was pulled in the right anterior direction. Upper right: schema of picture (arrow shows lifted right atrial diverticulum). Lower: upon opening, the thrombus was seen (wide arrow). RV: right ventricle.

has an entry into the right atrium. Considering these findings, our case was a single RAD. Treatment for RAD includes observation, anticoagulation, antiarrhythmic agents, radiofrequency catheter ablation, and surgical resection.1–3,5–7 Patients with RAD are at risk of developing a thrombus in the diverticulum, which has been reported in only 5.5% of cases.2 RAD patients often have a supraventricular arrhythmia, which may include ectopic, pre-excitatory, and reentrant arrythmias.8 If arrhythmia is present, antiarrhythmic drugs and radiofrequency ablation are advised. These modalities are not actually treating the RAD but treating its associated complications. It is reported that fatal arrhythmias, worsening tricuspid regurgitation, and sudden death can occur.3 Our case had a giant RAD that pressed on the right atrium and right ventricle, and a thrombus in the RAD was suspected. Therefore, we performed surgical resection. It has been reported that the wall of an enlarged RAD often demonstrates lipomatous degeneration and reduction of muscular elements,2 which the pathology findings also demonstrated in our case. Funding This research received no specific grant from any funding agency in the public, commerical, or not-for-profit sectors.

References 1. Gulati A, Gheta R, Chan CF, et al. Longitudinal followup of a right atrial appendage aneurysm by cardiac magnetic resonance imaging. Circulation 2011; 123: 2289–2291. 2. Binder TM, Rosenhek R, Frank H, Gwechenberger M, Maurer G and Baumgartner H. Congenital malformations of the right atrium and the coronary sinus: an analysis based on 103 cases reported in the literature and two additional cases. Chest 2000; 117: 1740–1748. 3. Narain VS, Puri A, Sethi R, et al. Giant right atrial aneurysm presenting as right heart failure. Indian Heart J 2012; 64: 200–202. 4. Rajbanshi BG, Phillips SD and Burkhart HM. Minimally invasive surgical resection of right atrial aneurysm. J Am Coll Cardiol 2011; 29: e41. 5. Kobza R, Oechslin E, Preˆtre R, Kurz DJ and Jenni R. Enlargement of the right atrium—diverticulum or aneurysm? Eur J Echocardiogr 2003; 4: 223–225. 6. Mizui S, Mori K and Kuroda Y. Ectopic atrial tachycardia due to aneurysm of the right atrial appendage. Cardiol Young 2001; 11: 229–232. 7. Duran NE, Ertu¨rk E, Gu¨ndu¨z S and Ozkan M. Aneurysm of the right atrial appendage in an elderly patient. Turk Kardiyol Dern Ars 2009; 37: 122–124. 8. Masuda S, Saiki Y, Itoh K and Sadahiro M. Surgical treatment of congenital right atrial aneurysm in an adult patient. Jpn J Thorac Cardiovasc Surg 2004; 52: 254–256.

Conflict of interest statement None declared.

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Giant right atrial diverticulum with thrombus formation.

A 28-year-old man was referred to our hospital with a giant right atrial diverticulum. The mass of the right atrial diverticulum compressed the right ...
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