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Subdivided left atrium mimicking a cardiac tumor
International Journal of Cardiology 68 (1999) 235–238
Subdivided left atrium mimicking a cardiac tumor a, a a b Kazuhiro Shimaya *, Akira Kurihashi , Naohide Tanaka , Masafumi Higashidate a
b
Department of Cardiology, Yokohama National Hospital, 252 Harajyuky-cho, Totsuka-ku, Yokohama 245, Japan Department of Cardiovascular Surgery, Yokohama National Hospital, 252 Harajyuky-cho, Totsuka-ku, Yokohama 245, Japan Received 30 July 1998; accepted 23 November 1998
Abstract We describe a 25-year-old man with a subdivided left atrium. The lesion was misdiagnosed preoperatively as a cardiac tumor because echocardiographic and magnetic resonance imaging revealed a solid mass arising from the posterior wall of the left atrium. Cardiac surgery revealed a small accessory chamber draining the two left pulmonary veins. No membranous structure was evident between the chamber and the left atrium. The solid mass identified noninvasively was a hypertrophic muscle which formed a wall of the accessory chamber. 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Subdivided left atrium; Mass; Left atrium; Echocardiography; MRI
1. Introduction Subdivided left atrium is a rare anomaly which represents 0.1% of all of the congenital heart defects that are detected. Symptoms caused by obstruction of pulmonary venous return usually develop within the first few years of life. There have been only a few reported cases of asymptomatic subdivided left atrium which were incidentally found in adulthood [1,2]. In those reported cases, the definitive diagnosis was made by echocardiography, computed tomography (CT), or magnetic resonance imaging (MRI), and demonstrated a membrane dividing the left atrium [1,2]. In this report, we describe an adult patient with a subdivided left atrium who presented with unusual radiologic findings.
*Corresponding author. Tel.: 181-45-851-2621; fax: 181-45-851-3902
2. Case report A 25-year-old man had a 6 month history of atypical chest pain. He had no abnormal findings on physical examination, routine laboratory examination, or chest radiography, except for a C-reactive protein concentration of 0.7 mg / dl. The interleukin-6 concentration was normal (0.621 pg / ml). Electrocardiography (ECG) demonstrated inverted T-wave in leads I, aVL, and V1-5. Treadmill exercise stress testing and Holter ECG revealed no additional ST-T changes. Transthoracic echocardiography (Fig. 1A and B) and MRI (Fig. 1C) revealed a mass in the left atrium. Transesophageal echocardiography (TEE; Fig. 2) demonstrated that the mass was attached to the posterior wall of the left atrium. Cardiac catheterization revealed a normal pulmonary arterial pressure (22 / 8 mm Hg; mean: 13 mm Hg) and a normal capillary wedge pressure (9 mm Hg). The venous return phase of pulmonary arterial angiography did not demonstrate the mass. Left ventriculography revealed normal wall motion.
0167-5273 / 99 / $ – see front matter 1999 Elsevier Science Ireland Ltd. All rights reserved. PII: S0167-5273( 98 )00359-3
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K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
Fig. 1. Transthoracic echocardiograph (A, B) and magnetic resonance image of the chest (C) showing a mass in the left atrium (arrow). No membranous structure was detected. (A) Long-axis view. (B) Short-axis view. (C) Horizontal view. LA5left atrium; LV5left ventricle; RV5right ventricle; Ao5aortic valve.
K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
237
Fig. 2. Transesophageal echocardiograph showing a mass attached to the posterior wall of the left atrium (arrow). LA5left atrium; LV5left ventricle; Ao5aortic valve.
Coronary angiography revealed no arteries feeding the mass and no significant stenoses. Because we could not exclude the presence of a cardiac tumor, the patient underwent exploratory cardiac surgery. There was a small accessory chamber located behind the true left atrium that received the two left pulmonary veins. The true left atrium received the two right pulmonary veins, and contained the fossa ovalis, the left atrial appendage, and mitral valve. The coronary sinus was normal. The accessory chamber connected with the true left atrium without a membranous structure. Based on the surgical findings, we made a diagnosis of subdivided left atrium. No other vascular anomalies were found. The
mass detected by echocardiography and MRI was the hypertrophic muscle of the accessory chamber wall. The patient required no surgical correction because the accessory chamber communicated with the true left atrium through a large ostium. After surgery, the patient complained of recurrent atypical chest pain. We believe that paroxysmal atrial fibrillation might be the cause of the pain.
3. Discussion A subdivided left atrium is characterized by two left atrial chambers [3]. There are various anatomic
238
K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
patterns, depending on the relationship of the abnormal partition to the pulmonary veins, the oval fossa, the left atrial appendage, and the mitral valve [3,4]. The anatomic pattern present in our patient has not been described previously. In most cases of subdivided left atrium, a fibromuscular membrane divides the left atrium into two chambers [3]. The diagnosis is easily made when imaging modalities demonstrate the dividing membrane [1,2]. In our patient, preoperative imaging suggested the presence of a solid mass in the left atrium in the absence of a membranous structure. This finding is more consistent with cardiac tumors or thrombi. We believe that a subdivided left atrium should be added to the differential diagnosis of a mass in the left atrium [4].
Acknowledgements The authors wish to express their grateful apprecia-
tion to Professor Hidezoh Aikawa (Department of Anatomy and Developmental Biology, Tokyo Women’s Medical College) for his invaluable advice.
References [1] Kacenelenbogen R, Decoodt P. Biplane transesophageal echocardiographic diagnosis of cor triatriatum. Chest 1994;105:601–2. [2] Tanaka F, Itoh M, Esaki H, Isobe J, Inoue R. Asymptomatic cor triatriatum incidentally revealed by computed tomography. Chest 1991;100:272–4. [3] Thilenius OG, Bharati S, Lev M. Subdivided left atrium: An expanded concept of cor triatriatum sinistrum. Am J Cardiol 1976;37:743–51. [4] Anderson RH. Understanding the nature of congenital division of the atrial chambers. Br Heart J 1992;68:1–3.
Subdivided left atrium mimicking a cardiac tumor a, a a b Kazuhiro Shimaya *, Akira Kurihashi , Naohide Tanaka , Masafumi Higashidate a
b
Department of Cardiology, Yokohama National Hospital, 252 Harajyuky-cho, Totsuka-ku, Yokohama 245, Japan Department of Cardiovascular Surgery, Yokohama National Hospital, 252 Harajyuky-cho, Totsuka-ku, Yokohama 245, Japan Received 30 July 1998; accepted 23 November 1998
Abstract We describe a 25-year-old man with a subdivided left atrium. The lesion was misdiagnosed preoperatively as a cardiac tumor because echocardiographic and magnetic resonance imaging revealed a solid mass arising from the posterior wall of the left atrium. Cardiac surgery revealed a small accessory chamber draining the two left pulmonary veins. No membranous structure was evident between the chamber and the left atrium. The solid mass identified noninvasively was a hypertrophic muscle which formed a wall of the accessory chamber. 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Subdivided left atrium; Mass; Left atrium; Echocardiography; MRI
1. Introduction Subdivided left atrium is a rare anomaly which represents 0.1% of all of the congenital heart defects that are detected. Symptoms caused by obstruction of pulmonary venous return usually develop within the first few years of life. There have been only a few reported cases of asymptomatic subdivided left atrium which were incidentally found in adulthood [1,2]. In those reported cases, the definitive diagnosis was made by echocardiography, computed tomography (CT), or magnetic resonance imaging (MRI), and demonstrated a membrane dividing the left atrium [1,2]. In this report, we describe an adult patient with a subdivided left atrium who presented with unusual radiologic findings.
*Corresponding author. Tel.: 181-45-851-2621; fax: 181-45-851-3902
2. Case report A 25-year-old man had a 6 month history of atypical chest pain. He had no abnormal findings on physical examination, routine laboratory examination, or chest radiography, except for a C-reactive protein concentration of 0.7 mg / dl. The interleukin-6 concentration was normal (0.621 pg / ml). Electrocardiography (ECG) demonstrated inverted T-wave in leads I, aVL, and V1-5. Treadmill exercise stress testing and Holter ECG revealed no additional ST-T changes. Transthoracic echocardiography (Fig. 1A and B) and MRI (Fig. 1C) revealed a mass in the left atrium. Transesophageal echocardiography (TEE; Fig. 2) demonstrated that the mass was attached to the posterior wall of the left atrium. Cardiac catheterization revealed a normal pulmonary arterial pressure (22 / 8 mm Hg; mean: 13 mm Hg) and a normal capillary wedge pressure (9 mm Hg). The venous return phase of pulmonary arterial angiography did not demonstrate the mass. Left ventriculography revealed normal wall motion.
0167-5273 / 99 / $ – see front matter 1999 Elsevier Science Ireland Ltd. All rights reserved. PII: S0167-5273( 98 )00359-3
236
K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
Fig. 1. Transthoracic echocardiograph (A, B) and magnetic resonance image of the chest (C) showing a mass in the left atrium (arrow). No membranous structure was detected. (A) Long-axis view. (B) Short-axis view. (C) Horizontal view. LA5left atrium; LV5left ventricle; RV5right ventricle; Ao5aortic valve.
K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
237
Fig. 2. Transesophageal echocardiograph showing a mass attached to the posterior wall of the left atrium (arrow). LA5left atrium; LV5left ventricle; Ao5aortic valve.
Coronary angiography revealed no arteries feeding the mass and no significant stenoses. Because we could not exclude the presence of a cardiac tumor, the patient underwent exploratory cardiac surgery. There was a small accessory chamber located behind the true left atrium that received the two left pulmonary veins. The true left atrium received the two right pulmonary veins, and contained the fossa ovalis, the left atrial appendage, and mitral valve. The coronary sinus was normal. The accessory chamber connected with the true left atrium without a membranous structure. Based on the surgical findings, we made a diagnosis of subdivided left atrium. No other vascular anomalies were found. The
mass detected by echocardiography and MRI was the hypertrophic muscle of the accessory chamber wall. The patient required no surgical correction because the accessory chamber communicated with the true left atrium through a large ostium. After surgery, the patient complained of recurrent atypical chest pain. We believe that paroxysmal atrial fibrillation might be the cause of the pain.
3. Discussion A subdivided left atrium is characterized by two left atrial chambers [3]. There are various anatomic
238
K. Shimaya et al. / International Journal of Cardiology 68 (1999) 235 – 238
patterns, depending on the relationship of the abnormal partition to the pulmonary veins, the oval fossa, the left atrial appendage, and the mitral valve [3,4]. The anatomic pattern present in our patient has not been described previously. In most cases of subdivided left atrium, a fibromuscular membrane divides the left atrium into two chambers [3]. The diagnosis is easily made when imaging modalities demonstrate the dividing membrane [1,2]. In our patient, preoperative imaging suggested the presence of a solid mass in the left atrium in the absence of a membranous structure. This finding is more consistent with cardiac tumors or thrombi. We believe that a subdivided left atrium should be added to the differential diagnosis of a mass in the left atrium [4].
Acknowledgements The authors wish to express their grateful apprecia-
tion to Professor Hidezoh Aikawa (Department of Anatomy and Developmental Biology, Tokyo Women’s Medical College) for his invaluable advice.
References [1] Kacenelenbogen R, Decoodt P. Biplane transesophageal echocardiographic diagnosis of cor triatriatum. Chest 1994;105:601–2. [2] Tanaka F, Itoh M, Esaki H, Isobe J, Inoue R. Asymptomatic cor triatriatum incidentally revealed by computed tomography. Chest 1991;100:272–4. [3] Thilenius OG, Bharati S, Lev M. Subdivided left atrium: An expanded concept of cor triatriatum sinistrum. Am J Cardiol 1976;37:743–51. [4] Anderson RH. Understanding the nature of congenital division of the atrial chambers. Br Heart J 1992;68:1–3.