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ECHOCARDIOGRAPHIC DIAGNOSIS OF LEFT ATRIAL THROMBUS - A CASE REPORT By Thomas B. Graboys, MD; Laurence J. Sloss, MD and Ira A. Ockene, MD
ABSTRACT We report a case of mitral stenosis with echocardiographic findings we consider diagnostic of left atrial thrombus. Scanning of the ultrasound beam from the left ventricular basalward to the left atrium (LA) demonstrates a consistent group of strong echoes within the LA and extending into the mitral orifice. Massive left atrial thrombosis was confirmed at operation.
The echocardiogram (ECHO) has become a useful noninvasive diagnostic technique in the evaluation of cardiovascular disease and has been applied to the detection of intracavitary cardiac masses. While atrial myxomas are usually readily diagnosed by ECHO, and the “classic” ECHO findings are well appreciated (I); a far more common clinical problem is that of mitral stenosis and suspected atrial thrombus. We report a case of operatively confirmed left atrial thrombus which demonstrated diagnostic ECHO findings. CASE REPORT
A 68 year old woman was admitted for evaluation of mitral valvular disease. There was a history of rheumatic fever as a child, with progressive dyspnea on exertion and fatigue over the twelve months preceding her current admission. The patient had sustained a cerebral embolus one year prior to admission. Medications on admission included digoxin 0.125 mg daily. Physical examination revealed an elderly woman with evident left hemiparesis. Blood pressure was 130/80 with an irregularly irregular pulse of 120 BPM. Jugular venous distension was present 10 cm above the angle of Lewis at 30”. Bibasilar crepitations were present. S1 was variable. There was a grade 2/6 apical systolic murFrom the Cardiovascular Division, Department of Medicine, Peter Bent Brigham Hospital and Harvard Medical School, Boston, Massachusetts. Received January 7, 1977; revision accepted March 1 4 , 1977. For reprints contact: Thomas B. Graboys. MD. Cardiovascular Laboratories, Harvard University School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115. 284
FIGURE 1. Motion (M) scan from the region of the anterior mitral valve leaflet (AMVL) to the aortic (Ao) root and left atrium (LA) demonstrating a mass of thickened echoes consistent with atrial thrombus. IVS = interventricular septum. Ao V L = aortic valve leaflets. ECG = electrocardiogram.
mur and a grade 2/4 low-pitched diastolic murmur not preceded by an opening snap. Chest xray demonstrated increased vascular markings and a large left atrium. Electrocardiogram revealed coarse atrial fibrillation with a rapid ventricular response. Echocardiogram (preoperatively ) (Figure 1): The ECHO was performed using a Smith Kline Ekoline 20A ultrasonoscope with a focused transducer operated at a frequency of 2.25 MHz with a focal length of 7.5 cm. The echocardiogram was recorded on an Electronics for Medicine DR 8 multichannel strip chart recorder. Scanning the transducer beam basally from the region of the anterior mitral valve leaflet to the mitral annulus and thence to the left atrium revealed an abnormal, dense group of echoes presenting in the mitral orifice and occupying most of the left atrial cavity. The JOURNAL OF CLINICAL ULTRASOUND
strength of the echoes was demonstrated by their persistence at high attenuation. The mitral valve showed typical rheumatic deformity without calcification. The motion of the valve was consistent with severe stenosis. Cardiac catheterization revealed a pulmonary artery pressure of 44/30mmHg, right ventricular pressure of 44/5 mmHg, left ventricular end diastolic pressure of 3 mmHg with a pulmonary capillary wedge pressure of 27 mmHg. There was a mean diastolic mitral gradient of 20 mmHg at rest. Calculated mitral valve area was 0.5 cm2. Selective coronary angiography revealed nonobstructive luminal irregularities. Left ventriculography did not demonstrate mitral regurgitation. The ejection fraction was 49 per cent. Operative Note: The patient underwent replacement of her mitral valve with a small Beall mitral prosthesis. After initiating cardiopulmonary bypass, the left atrium was opened and found to be filled with an extensive thrombus adherent to all surfaces of the atrium and measuring 4 x 3 x 2 cm when submitted to pathology. Gross and histologic examination was consistent with fresh and old thrombus. DISCUSSION
This case demonstrates the diagnostic potential of echocardiography in the diagnosis of a left atrial thrombus. Our findings are similar t o a recent communication of Spangler and Okin (2), demonstrating the localization of abnormal echoes within the left atrium and extending to the mitral annulus. Poehlmann (3) described a left atrial thrombus in which transducer position and manipulation of ECHO sensitivity was necessary to demonstrate an abnormal and persistent moving echo. In an earlier communication, Tallury and DePasquale ( 4 ) suggested that ultrasound was not reliable for detecting atrial thrombus based on two of five patients with mitral stenosis who had false positive echocardiograms for left atrial thrombus. Their study emphasized persistent “layering” of echoes posterior
VOLUME 5 . NUMBER 4
to the anterior leaflet of the mitral valve, suggesting that this finding could be produced by blood flow patterns; they further stated that ultrasound techniques would not demonstrate a thrombus fixed to the atrium. Feigenbaum (1) cautions that fuzzy echoes (possibly misconstrued as clot) in the vicinity of the posterioi left atrial wall are not uncommon and may represent relatively stagnant blood near the atrial wall. We believe the present case demonstrates those findings compatible with the presence of a very large left atrial thrombus: strong abnormal echoes in the left atrium, persisting at low recorder gain and localized by careful “scanning” of the echo beam. The recording of similar findings, particularly in the presence of mitral stenosis, should be considered strong evidence of massive left atrial thrombus. The absence of motion of the abnormal echoes does not vitiate the reliability of the findings, and presumably reflects fixation of the thrombus t o the atrial wall. Lack of sensitivity (“false negative study”) is to be expected in cases where the thrombus is small and/or localized to the atrial appendage; indistinct, weak or otherwise “nondiagnostic” echoes might arise from a homogeneous thrombus which contains no strong echo producing interfaces. Differentiation ffom atrial myxoma is important but should present no problem in most cases because of the almost universal association of left atrial thrombosis with severe rheumatic mitral valve disease and atrial enlargement.
REFERENCES
1. Feigenbaum H: Echocardiography. Philadelphia, Lea and Febiger, 1972, pp. 152-161. 2. Spangler RD and Okin JT: Echocardiographic demonstration of a left atrial thrombus. Chest 67:716, 1975. 3. Poehlmann HW, Basta LL, and Brown RE: Left atrial thrombus detected by ultrasound. A case report, J Clin Ultrasound 3:65,1975. 4. Tallury K and DePasquale NP: Ultrasound cardiography in the diagnosis of left atrial thrombus. Chest 59:501,1971.
285
ECHOCARDIOGRAPHIC DIAGNOSIS OF LEFT ATRIAL THROMBUS - A CASE REPORT By Thomas B. Graboys, MD; Laurence J. Sloss, MD and Ira A. Ockene, MD
ABSTRACT We report a case of mitral stenosis with echocardiographic findings we consider diagnostic of left atrial thrombus. Scanning of the ultrasound beam from the left ventricular basalward to the left atrium (LA) demonstrates a consistent group of strong echoes within the LA and extending into the mitral orifice. Massive left atrial thrombosis was confirmed at operation.
The echocardiogram (ECHO) has become a useful noninvasive diagnostic technique in the evaluation of cardiovascular disease and has been applied to the detection of intracavitary cardiac masses. While atrial myxomas are usually readily diagnosed by ECHO, and the “classic” ECHO findings are well appreciated (I); a far more common clinical problem is that of mitral stenosis and suspected atrial thrombus. We report a case of operatively confirmed left atrial thrombus which demonstrated diagnostic ECHO findings. CASE REPORT
A 68 year old woman was admitted for evaluation of mitral valvular disease. There was a history of rheumatic fever as a child, with progressive dyspnea on exertion and fatigue over the twelve months preceding her current admission. The patient had sustained a cerebral embolus one year prior to admission. Medications on admission included digoxin 0.125 mg daily. Physical examination revealed an elderly woman with evident left hemiparesis. Blood pressure was 130/80 with an irregularly irregular pulse of 120 BPM. Jugular venous distension was present 10 cm above the angle of Lewis at 30”. Bibasilar crepitations were present. S1 was variable. There was a grade 2/6 apical systolic murFrom the Cardiovascular Division, Department of Medicine, Peter Bent Brigham Hospital and Harvard Medical School, Boston, Massachusetts. Received January 7, 1977; revision accepted March 1 4 , 1977. For reprints contact: Thomas B. Graboys. MD. Cardiovascular Laboratories, Harvard University School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115. 284
FIGURE 1. Motion (M) scan from the region of the anterior mitral valve leaflet (AMVL) to the aortic (Ao) root and left atrium (LA) demonstrating a mass of thickened echoes consistent with atrial thrombus. IVS = interventricular septum. Ao V L = aortic valve leaflets. ECG = electrocardiogram.
mur and a grade 2/4 low-pitched diastolic murmur not preceded by an opening snap. Chest xray demonstrated increased vascular markings and a large left atrium. Electrocardiogram revealed coarse atrial fibrillation with a rapid ventricular response. Echocardiogram (preoperatively ) (Figure 1): The ECHO was performed using a Smith Kline Ekoline 20A ultrasonoscope with a focused transducer operated at a frequency of 2.25 MHz with a focal length of 7.5 cm. The echocardiogram was recorded on an Electronics for Medicine DR 8 multichannel strip chart recorder. Scanning the transducer beam basally from the region of the anterior mitral valve leaflet to the mitral annulus and thence to the left atrium revealed an abnormal, dense group of echoes presenting in the mitral orifice and occupying most of the left atrial cavity. The JOURNAL OF CLINICAL ULTRASOUND
strength of the echoes was demonstrated by their persistence at high attenuation. The mitral valve showed typical rheumatic deformity without calcification. The motion of the valve was consistent with severe stenosis. Cardiac catheterization revealed a pulmonary artery pressure of 44/30mmHg, right ventricular pressure of 44/5 mmHg, left ventricular end diastolic pressure of 3 mmHg with a pulmonary capillary wedge pressure of 27 mmHg. There was a mean diastolic mitral gradient of 20 mmHg at rest. Calculated mitral valve area was 0.5 cm2. Selective coronary angiography revealed nonobstructive luminal irregularities. Left ventriculography did not demonstrate mitral regurgitation. The ejection fraction was 49 per cent. Operative Note: The patient underwent replacement of her mitral valve with a small Beall mitral prosthesis. After initiating cardiopulmonary bypass, the left atrium was opened and found to be filled with an extensive thrombus adherent to all surfaces of the atrium and measuring 4 x 3 x 2 cm when submitted to pathology. Gross and histologic examination was consistent with fresh and old thrombus. DISCUSSION
This case demonstrates the diagnostic potential of echocardiography in the diagnosis of a left atrial thrombus. Our findings are similar t o a recent communication of Spangler and Okin (2), demonstrating the localization of abnormal echoes within the left atrium and extending to the mitral annulus. Poehlmann (3) described a left atrial thrombus in which transducer position and manipulation of ECHO sensitivity was necessary to demonstrate an abnormal and persistent moving echo. In an earlier communication, Tallury and DePasquale ( 4 ) suggested that ultrasound was not reliable for detecting atrial thrombus based on two of five patients with mitral stenosis who had false positive echocardiograms for left atrial thrombus. Their study emphasized persistent “layering” of echoes posterior
VOLUME 5 . NUMBER 4
to the anterior leaflet of the mitral valve, suggesting that this finding could be produced by blood flow patterns; they further stated that ultrasound techniques would not demonstrate a thrombus fixed to the atrium. Feigenbaum (1) cautions that fuzzy echoes (possibly misconstrued as clot) in the vicinity of the posterioi left atrial wall are not uncommon and may represent relatively stagnant blood near the atrial wall. We believe the present case demonstrates those findings compatible with the presence of a very large left atrial thrombus: strong abnormal echoes in the left atrium, persisting at low recorder gain and localized by careful “scanning” of the echo beam. The recording of similar findings, particularly in the presence of mitral stenosis, should be considered strong evidence of massive left atrial thrombus. The absence of motion of the abnormal echoes does not vitiate the reliability of the findings, and presumably reflects fixation of the thrombus t o the atrial wall. Lack of sensitivity (“false negative study”) is to be expected in cases where the thrombus is small and/or localized to the atrial appendage; indistinct, weak or otherwise “nondiagnostic” echoes might arise from a homogeneous thrombus which contains no strong echo producing interfaces. Differentiation ffom atrial myxoma is important but should present no problem in most cases because of the almost universal association of left atrial thrombosis with severe rheumatic mitral valve disease and atrial enlargement.
REFERENCES
1. Feigenbaum H: Echocardiography. Philadelphia, Lea and Febiger, 1972, pp. 152-161. 2. Spangler RD and Okin JT: Echocardiographic demonstration of a left atrial thrombus. Chest 67:716, 1975. 3. Poehlmann HW, Basta LL, and Brown RE: Left atrial thrombus detected by ultrasound. A case report, J Clin Ultrasound 3:65,1975. 4. Tallury K and DePasquale NP: Ultrasound cardiography in the diagnosis of left atrial thrombus. Chest 59:501,1971.
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