Left Atrial Thrombus Causing Pulmonary Embolism by Passing Through an Atrial Septal Defect

Abstract

eft atrial thrombus sometimes accompanies atrial fibrillation (AF) and in the absence of rheumatic valvular disease, is associated with a 5-to 7-fold increased risk of ischemic stroke caused by the thrombus; 1 the rate has been reported to be 6.3% per year. 1 Furthermore, left atrial thrombi can also embolize to abdominal or pelvic organs and in Japan, it has been reported that the annual incidence of thromboembolic complications is 2.1% in non-valvular heart disease. 2 However, there are no reports in the literature of left atrial thrombus causing pulmonary embolism by passing through an atrial septal defect (ASD) and we present the first case in which a left atrial thrombus caused by AF embolized to the pulmonary artery via an ASD, causing pulmonary embolism. Case ReportA 66-year-old Japanese woman was admitted with dyspnea on exertion. She had a history of a hepatic disorder at 62 years of age. Her symptoms had been getting worse for more than 1 year, and the degree of dyspnea on admission corresponded to New York Heart Association grade III. Her blood pressure was 142/90 mmHg and her heart rate was irregular and about 150 beats/min at the time of admission. Physical examination did not detect jugular venous distention, hepatomegaly or splenomegaly, but there was pretibial edema. Auscultation of the chest revealed slight bilateral inspiratory crackles at the lung bases and a grade III/VI systolic murmur along the left sternal border of the second intercostal space. Blood testing showed no specific abnormalities, but arterial blood gas analysis while the Circulation Journal Vol.66, January 2002 patient was on nasal oxygen (2 L/min) revealed a PaO2 of 66.0 mmHg and a PaCO2 of 33.0 mmHg. Her electrocardiogram showed AF and poor R wave progression in V1-3. The chest radiograph showed pulmonary congestion and bilateral pleural effusions.Transthoracic echocardiography revealed a highly echogenic mobile mass (24×17 mm) in the dilated left atrium (left atrial diameter: 57 mm; Fig 1), and diffuse left ventricular hypokinesis (ejection fraction: 47%; fractional shortening: 21%) without left ventricular dilation (left ventricular end-diastolic diameter: 49 mm; left ventricular end-systolic diameter: 38 mm). The right atrium and right ventricle were mildly dilated, and shunt flow from the left atrium to the right atrium was clearly detected by color Doppler echocardiography, suggesting the existence of an ASD. Mild mitral and tricuspid regurgitation were diagnosed, but we did not find aortic or pulmonary regurgitation. Transesophageal echocardiography clearly showed an ASD (8.2 mm in maximum diameter; Fig 2). The mass appeared to adhere to the A 66-year-old woman admitted with dyspnea on exertion had atrial fibrillation and left ventricular dysfunction. Echocardiography revealed an atrial septal defect (ASD) and a soft, easily deformable thrombus in the dilated left atrium. The atrial mass suddenly disappeared on the 10th day after admission, and contrast-enhanced chest computed tomography and pulmonary blood flow scinti...

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“…As already said, PE of cardiac origin has a rightsided location; however, in a few cases, left-sided sources have been described (Ishihara et al 2002).…”

A cryptogenic pulmonary embolism: Left atrial myxoma occluding an atrial septal defect

“…Pulmonary embolism generally has a right-sided origin; however, a few cases of left-sided sources have been described. 3 Obviously, these conditions are always associated with some form of cross-circulation allowing the embolic mass to pass from the left to the right side of the heart. The most frequent left-sided sources of pulmonary embolism reported in the literature are LA thrombi, often the result of mitral valve stenosis or atrial fibrillation.…”

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