Superiority of transesophageal echocardiography in detecting cardiac source of embolism in patients with cerebral ischemia of uncertain etiology

The diagnostic yield of transesophageal and transthoracic echocardiography for identifying a cardiac source of embolism was compared in 79 patients presenting with unexplained stroke or transient ischemic attack. There were 35 men and 44 women with a mean age of 59 years (range 17 to 84); 52% had clinical cardiac disease. Both transthoracic and transesophageal echocardiograms were performed using Doppler color flow and contrast imaging. Transesophageal echocardiography identified a potential cardiac source of embolism in 57% of the overall study group compared with only 15% by transthoracic echocardiography (p less than 0.0005). Compared with transthoracic echocardiography, transesophageal echocardiography more frequently identified atrial septal aneurysm associated with a patent foramen ovale (9 versus 1 of 79 patients, p less than 0.005), left atrial thrombus or tumor (6 versus 0 of 79 patients, p less than 0.05) and left atrial spontaneous contrast (13 versus 0 of 79 patients, p less than 0.0005). All cases of left atrial thrombus or spontaneous contrast were identified in patients with clinically identified cardiac disease. In the 38 patients with no cardiac disease, transesophageal echocardiography identified isolated atrial septal aneurysm and atrial septal aneurysm with a patent foramen ovale more frequently than transthoracic echocardiography (8 versus 2 of 38 patients, p less than 0.05). The two techniques had a similar rate of identifying apical thrombus and mitral valve prolapse. Overall, transesophageal echocardiography identified abnormalities in 39% of patients with no cardiac disease versus 19% for transthoracic echocardiography (p less than 0.005). Thus, transesophageal echocardiography identifies potential cardiac sources of embolism in the majority of patients presenting with unexplained stroke.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnostic value of transesophageal echocardiography in atrial septal aneurysm

Transthoracic and transesophageal echocardiography was performed in 40 consecutive adult patients with an atrial septal aneurysm. In 11 (27%) of 40 patients transthoracic echocardiography failed to demonstrate the lesion and the diagnosis was established by the transesophageal approach only. Interatrial shunting, assessed by echocardiographic contrast study and/or color flow mapping, was detected in 13 (54%) of 24 patients on transthoracic imaging and in 29 (76%) of 38 patients during transesophageal echocardiography. Identification of multiple fenestrations (n=9) and thrombi within the aneurysm (n=2) could be achieved only by transesophageal ultrasound. A cerebrovascular event of suspected embolic origin occurred in 20 (50%) of 40 patients; 11 (55%) of the 20 patients had repeated cerebral events. Except for mitral valve prolapse in 2 patients and spontaneous left atrial contrast phenomenon in 1 patient no other potential cardiac source of embolism could be identified by transesophageal echocardiography. A marked thickening of the aneurysm was present in 14 (70%) of 20 patients with a cerebrovascular event versus only 4 (20%) of 20 patients without a cerebrovascular event (p<0,01). The mechanism of embolization may be both primary thrombus formation within the aneurysm and paradoxical embolization through an interatrial communication as suggested by the findings on transesophageal ultrasound in 2 patients. Although the patients of this study represent a highly selected group it may be concluded that atrial septal aneurysm is a cardiac abnormality with embolic potential. Transesophageal echocardiography has to be regarded the imaging method of choice for evaluation of this lesion.     

The role of transesophageal echocardiography in the detection of left atrial thrombi

Sensitivity of transthoracic echocardiography in the detection of left atrial thrombi, in particular thrombi confined to the left atrial appendage, is surprisingly low (33%-72%). Concerning the detection of left atrial thrombi, transthoracic echocardiography appears as an inadequate technique in patients with suspected cardiogenic embolism with a success rate of only 0.8% in earlier, and about 3% in recent studies. Imaging from the esophagus substantially increases the detection rate for left atrial thrombi, and is the only clinically relevant semiinvasive technique to diagnose thrombi confined to the left atrial appendage. Transesophageal echocardiography has markedly increased the diagnostic power of cardiovascular ultrasound in patients with suspected cardiogenic embolism and/or atrial fibrillation. Meta-analysis of pooled studies using the transesophageal approach in these patients revealed thrombi within the left atrial cavity in about 7% and within the atrial appendage in about 12% of cases.     

Transesophageal echocardiography in the definition of intracardiac sources of emboli in patients with recent ischemic stroke

Using both transthoracic and transesophageal echocardiography we studied 13 consecutive patients with recent CT-proven ischemic stroke in which a carotid arteries high-resolution ultrasound study failed to detect thrombosis or other relevant atherosclerotic lesions in the pertinent arteries. The mean age was 53 years (range: 36-65). Two patients exhibited clinical signs of cardiac disease at physical examination i.e. absolute arrhythmia, mitral stenosis. Conventional transthoracic echocardiography allowed the detection of potential cardiac sources of emboli in 2/13 patients (15.4%): mitral stenosis in one patient and dilated cardiomyopathy in another. Transesophageal echocardiography was successfully performed without general sedation in all patients. Potential cardiac sources of emboli could be identified in 12/13 patients (92%). Left atrial thrombi were found in 3 patients: in two of them they were associated with rheumatic alterations of mitral valve leaflets; in the third patient a small thrombus was located inside a normal-sized, poorly contracting left atrial appendage. Left atrial appendage could be clearly visualized in all patients. A myxoid degeneration of a prolapsing mitral leaflet was found in 3 patients and an interatrial septum aneurysm in 2. Furthermore, at color-flow Doppler and contrast transesophageal echocardiography, 7 patients (54%) showed patency of the foramen ovale. In 5 of these patients paradoxical right to left shunting after cough or Valsalva manoeuvre could be evidenced. With reference to 11/13 patients with no clinical signs of cardiac disease at physical examination, subclinical potential cardiac sources of emboli could be detected at conventional transthoracic echocardiography in 1 and at transesophageal echocardiography in 10 patients (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Transesophageal echocardiography in the evaluation of stroke.

OBJECTIVE: To review the current role of transesophageal echocardiography in the evaluation of stroke. DATA IDENTIFICATION: Articles examining the role of transesophageal echocardiography for evaluation of patients with stroke were identified using computer and bibliography searches. STUDY SELECTION: All English-language articles that provided full details on patient selection criteria, methods, and study design were reviewed. RESULTS OF DATA ANALYSIS: Cardiogenic embolism is frequently an uncertain diagnosis merely inferred by finding a potential cardiac source. Transthoracic echocardiography has had a low yield in screening unselected patients with stroke. Several series of patients with stroke have been reported comparing transthoracic and transesophageal echocardiography. Potential cardiac sources of embolism were consistently identified in many more patients by transesophageal echocardiography. Many findings are, however, of uncertain significance; these include spontaneous echo contrast, patent foramen ovale, filamentous strands on the mitral valve, and atrial septal aneurysm. CONCLUSIONS: Transesophageal echocardiography is most helpful in patients with stroke who are less than 45 years of age and in those without clinical evidence of heart disease. The indications for its use in the evaluation of stroke remain controversial. Further studies are needed using transesophageal echocardiography in patients with stroke and in control groups, not only to determine the natural history of transesophageal, echocardiographically detected abnormalities but also to evaluate treatment options.     

Role of transoesophageal echocardiography in evaluation of cardiogenic embolism.

OBJECTIVE--To determine the value of transoesophageal echocardiography in the assessment of selected patients at risk of cardiogenic embolism or after it. DESIGN--Prospective comparison of the results of transoesophageal and transthoracic echocardiography. Transoesophageal echocardiography was performed with a 5 MHz single plane phased array transducer. SETTING--University teaching hospital. PATIENTS--100 patients referred for transoesophageal echocardiography after a cerebral ischaemic event or peripheral arterial embolism (n = 63), before percutaneous balloon dilatation of the mitral valve (n = 23), or before electrical cardioversion of atrial fibrillation (n = 14). RESULTS--Transthoracic echocardiography showed potential sources of embolism in four patients including left ventricular thrombus in two patients (with one false positive), left atrial appendage thrombus (n = 1), and patent foramen ovale (n = 1). Transoesophageal echocardiography showed 59 potential embolic sources in 45 patients including left atrial spontaneous echo contrast (n = 33), left atrial appendage thrombus (n = 13), left ventricular thrombus (n = 5), patent foramen ovale (n = 3), left ventricular spontaneous echo contrast (n = 2), mitral valve prosthesis thrombus (n = 1), mitral valve prolapse (n = 1), and pronounced aortic atheroma (n = 1). Transoesophagal echocardiography showed potential embolic sources in 36/53 (68%) patients with atrial fibrillation compared with 9/47 (19%) patients in sinus rhythm. Percutaneous balloon dilatation of the mitral valve was performed without embolic complications in 18 patients without left atrial thrombi and in three patients with small fixed thrombi in the left atrial appendage. It was cancelled in two patients with large thrombi in the left atrial appendage. Cardioversion was performed without embolic complications in 14 patients without left atrial thrombi. CONCLUSIONS--Transoesophageal echocardiography detects potential sources of embolism better than transthoracic echocardiography in selected patients at risk of cardiogenic embolism or after it.     

Role of transoesophageal echocardiography in evaluation of cardiogenic embolism.

OBJECTIVE--To determine the value of transoesophageal echocardiography in the assessment of selected patients at risk of cardiogenic embolism or after it. DESIGN--Prospective comparison of the results of transoesophageal and transthoracic echocardiography. Transoesophageal echocardiography was performed with a 5 MHz single plane phased array transducer. SETTING--University teaching hospital. PATIENTS--100 patients referred for transoesophageal echocardiography after a cerebral ischaemic event or peripheral arterial embolism (n = 63), before percutaneous balloon dilatation of the mitral valve (n = 23), or before electrical cardioversion of atrial fibrillation (n = 14). RESULTS--Transthoracic echocardiography showed potential sources of embolism in four patients including left ventricular thrombus in two patients (with one false positive), left atrial appendage thrombus (n = 1), and patent foramen ovale (n = 1). Transoesophageal echocardiography showed 59 potential embolic sources in 45 patients including left atrial spontaneous echo contrast (n = 33), left atrial appendage thrombus (n = 13), left ventricular thrombus (n = 5), patent foramen ovale (n = 3), left ventricular spontaneous echo contrast (n = 2), mitral valve prosthesis thrombus (n = 1), mitral valve prolapse (n = 1), and pronounced aortic atheroma (n = 1). Transoesophagal echocardiography showed potential embolic sources in 36/53 (68%) patients with atrial fibrillation compared with 9/47 (19%) patients in sinus rhythm. Percutaneous balloon dilatation of the mitral valve was performed without embolic complications in 18 patients without left atrial thrombi and in three patients with small fixed thrombi in the left atrial appendage. It was cancelled in two patients with large thrombi in the left atrial appendage. Cardioversion was performed without embolic complications in 14 patients without left atrial thrombi. CONCLUSIONS--Transoesophageal echocardiography detects potential sources of embolism better than transthoracic echocardiography in selected patients at risk of cardiogenic embolism or after it.     

Transesophageal echocardiography to detect atrial clots in candidates for percutaneous transseptal mitral balloon valvuloplasty

Left atrial thrombi are common in patients with mitral stenosis. When percutaneous balloon mitral valvuloplasty is performed on such patients, there is a potential risk of thrombus dislodgment and embolization. In this study conventional transthoracic echocardiography and transesophageal echocardiography were performed for percutaneous balloon mitral valvuloplasty on 19 consecutive candidates (6 men, 13 women, 23 to 81 years old). In five patients (26%), transesophageal echocardiography revealed a left atrial thrombus; in only one of these was there a suspicion of left atrial thrombus on transthoracic echocardiography. Balloon mitral valvuloplasty was canceled in four of the five patients. Three underwent mitral valve surgery that confirmed the echocardiographic findings. Transesophageal echocardiography is better than conventional transthoracic echocardiography in detecting left atrial clots in candidates for balloon mitral valvuloplasty. Because of the potential risk of embolization, transesophageal echocardiography is recommended in all candidates for balloon mitral valvuloplasty.     

Assessment of left atrial appendage by live three-dimensional echocardiography: early experience and comparison with transesophageal echocardiography

BACKGROUND: Live Three-Dimensional Echocardiography (L3D, Sonos 7500, Philips) has the potential to visualize all cardiac structures including left atrial appendage (LAA). We tested the feasibility of evaluating LAA by L3D and compared the findings to transthoracic echocardiography (2D) and in a subset of patients with transesophageal echocardiography (TEE). METHODS: L3D images were obtained in 204 consecutive patients referred for routine 2D or TEE. We performed wide-angled acquisitions from parasternal and apical views. TomTec system (4D Cardio-view, RT 1.2) was used to visualize LAA from multiple vantage points. RESULTS: LAA was adequately visualized by L3D in 139 of 204 (68.1%) patients. L3D visualization was dependent on image quality, suboptimal in 100 and diagnostic in 104 patients. Overall, LAA was visualized in 93 (45.5%) patients by 2D compared to 139 (68.1%) by L3D (P < 0.0001). In 100 patients with suboptimal image quality by L3D, LAA visualization was 16% by 2D and 35% by L3D, whereas in 104 patients with diagnostic images, LAA was visualized in 77 (74%) by 2D and in all 104 (100%) patients by L3D (P < 0.0001). In 37 patients referred for transesophageal echocardiography (TEE), live three-dimensional echocardiography (L3D) visualized left atrial appendage (LAA) in 34 patients with diagnostic image quality. Eight patients with LAA thrombi on TEE had thrombi detected by L3D as well. All patients with LAA thrombus had enlarged LA by both 2D and TEE. CONCLUSIONS: L3D is a promising technique in evaluation of LAA with and without thrombi. In patients with good quality transthoracic images L3D may be used as a screening tool in assessment of LAA.     

Left atrial thrombi despite anticoagulant and antiplatelet therapy

To investigate risk factors for embolization in patients with echocardiographically detected left atrial thrombi and to evaluate thrombus development, we examined 29 patients with transesophageal and transthoracic echocardiography at two points during a follow-up of 18 months. We compared patients with a history of possible arterial embolization0 (n = 13) with those without (n = 16) in regard to age, gender, left atrial dilatation, localization of the thrombus in the left atrial cavity, spontaneous echo contrast, and atrial fibrillation. Eight patients were treated with aspirin, 20 with phenprocoumon. Only left atrial spontaneous contrast was associated with thrombembolism (10/15 patients with spontaneous contrast experienced arterial embolism; p = 0.038). in six patients arterial embolism occurred after thrombus detection (14% per patient per year). Four of these patients were treated with phenprocoumon, two with aspirin. At reexamination, one thrombus was detected in the patient without anticoagulant treatment and one thrombus was detected in the 8 patients treated with aspirin (13%), compared with ten thrombi detected in the 20 patients (50%) treated with phenprocoumon (p = NS). in 17 patients no thrombus was seen at reexamination. Since only 2 patients had undergone thrombectomy and 3 experienced arterial embolism during follow-up, thrombi disappeared under medical therapy in 12 patients. Patients with left atrial thrombi have a high risk of arterial embolization despite proper anticoagulative or antiplatelet treatment. Embolization occurs significantly more often if spontaneous echo contrast can be visualized. Left atrial thrombi can be reduced in size by the administration of antiplatelet and anticoagulative agents. Detection of left atrial thrombi with transesophageal echocardiography identifies this patient population at an increased risk of embolization.     

The value of transesophageal echocardiography in predicting immediate and long-term outcome of balloon mitral valvuloplasty: comparison with transthoracic echocardiography

The purpose of this study was to assess the role of transesophageal echocardiography in predicting the immediate and long-term outcome of balloon mitral valvuloplasty, and compare the results to transthoracic echocardiography. BACKGROUND: Transesophageal echocardiography accurately detects left atrial thrombi and allows better visualization of mitral valve morphology; however, its value in predicting the immediate and long-term outcome of balloon mitral valvuloplasty had not been assessed as adequately as for transthoracic echocardiography. METHODS: In 56 patients referred for balloon mitral valvuloplasty, both transesophageal and transthoracic echocardiography were performed (Group A). An echo score for both techniques was used to reflect mitral valve morphology, and its predictive value for immediate and long-term outcome of the valvuloplasty was assessed. The impact of transesophageal echocardiography in preventing procedural embolic events in those 56 patients was assessed by comparison to another group of 41 patients, who were examined only by transthoracic echocardiography prior to balloon mitral valvuloplasty (Group B). RESULTS: In Group A, transesophageal echocardiography detected left atrial thrombus in seven, while transthoracic echocardiography detected left atrial thrombus in two patients. After 2 months of warfarin therapy, a repeat transesophageal echo examination in four patients showed resolution of thrombus in three who went on to have balloon mitral valvuloplasty. Among the 52 patients who eventually had the procedure after thrombus was excluded by transesophageal echocardiography, there were no embolic events, compared to three embolic events among the 41 patients in Group B (P = 0.08). The transthoracic echocardiography scores, while slightly higher, correlated well with transesophageal echocardiography scores (r = 0.51, P < 0.001). The increase in mitral valve area did not correlate well to total transthoracic or transesophageal echocardiography scores, while it correlated negatively to valve calcification by transthoracic (r = -0.29, P < 0.05) and mobility by transesophageal echocardiography (r = -0.59, P < 0.02). At follow-up (7 +/- 4 months) nonsurvivors (7/56) had higher total scores by either transthoracic (P < 0.01) or transesophageal echocardiography (P < 0.05) compared to survivors. The percent reduction in mitral valve area was greater with age (r = 0.5, P < 0.02), time to follow-up (r = 0.67, P < 0.002), valve mobility by transthoracic echocardiography (r = 0.59, P < 0.01), and valve calcification by transthoracic echocardiography (r = 0.37, P = 0.09) and transesophageal echocardiography (r = 0.4, P = 0.07). CONCLUSIONS: Transesophageal echocardiography is superior to transthoracic echocardiography in detecting left atrial thrombi, and it may reduce the risk of embolic events following balloon mitral valvuloplasty. Assessment of mitral valve morphology by transesophageal echocardiography is complementary and not superior to assessment by transthoracic echocardiography. Mitral valve calcification and mobility appear to be the best morphological predictors of immediate and long-term outcome following balloon mitral valvuloplasty.     

Risk of thromboembolism in acute atrial fibrillation or atrial flutter

Atrial fibrillation (AF) is the most common sustained cardiac dysrhythmia, predominating in the elderly, with stroke as a potentially devastating complication. Prevention of the thromboembolic sequelae from AF remains a central focus of practicing clinicians. Although the risk of thromboembolism in chronic AF is well recognized, less is known about the potential risk of systemic embolism in acute AF. In addition, recent data support the notion of a group at considerable risk of embolism from atrial flutter, an arrhythmia typically believed to bestow little increased risk of thromboembolism. The mechanism of thrombus formation, embolization, and resolution in atrial arrhythmias is not well defined, particularly in that of acute AF or atrial flutter. The traditional concept proposes that atrial thrombus forms only after > 2 days of AF and embolizes by being dislodged from increases in shear forces. This widely accepted concept further holds that newly formed atrial thrombus, in the setting of AF, organizes over a span of 14 days. The results of studies based on observations from transesophageal echocardiography examinations have provided provocative insight into the temporal sequence of atrial thrombus formation, embolization, and resolution in AF or atrial flutter and have expanded the traditional concept of thromboembolism in these atrial dysrhythmias. Namely, left atrial thrombus may form before the onset of AF in the face of sinus rhythm. Conversion to sinus rhythm may increase the thrombogenic milieu of the left atrium. Importantly, atrial thrombus may form in the acute phase of AF. Last, thrombi may require > 14 days to become immobile or to resolve. Findings similar to those of acute AF have been reported in patients with atrial flutter and coexisting cardiac pathology. On the basis of these emerging insights fostered by the use of transesophageal echocardiography, it appears appropriate to consider anticoagulation in patients presenting with acute AF or atrial flutter with coexisting cardiac pathology predisposing to left atrial thrombus.     

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.     

Current incidence of peripheral arterial embolism and role of echocardiography

We reviewed the incidence and outcome of all cases of upper and lower limb embolism surgically treated in our vascular unit, from January 2001 to June 2006, to assess the role of transthoracic and transesophageal echocardiography in defining the source of the embolus. Transthoracic echocardiography was carried out postoperatively, and patients in whom the embolic source was not found underwent transesophageal echocardiography. There were 85 patients (mean age, 69 years) who underwent embolectomy: 58 for lower and 27 for upper limb ischemia. The source or potential source of thrombus was demonstrated in 17 (20%) patients after transthoracic echocardiography. Fifty-three patients had transesophageal echocardiography, the source of embolism was found in 85%, and the subsequent management was changed in 47% of them. Arterial limb emboli are still prevalent in developing countries. Transthoracic echocardiography is a good screening tool for detecting a potential cardiac source of peripheral embolism, with transesophageal echocardiography being reserved for specific indications.     

Transesophageal echocardiography and stroke

Only coronary artery disease and cancer kill more people than stroke in the United States. Transesophageal echocardiography (TEE) is a semi-invasive ultrasound cardiac imaging technique that provides superior anatomic detail as well as functional information. Searching for a cause of cerebral ischemia is the most common indication for TEE in cardiac ultrasound laboratories. Although TEE is not superior to transthoracic imaging for identifying all sources of cardiac embolism, its ability to more sensitively detect atrial septal aneurysm, patent foramen ovale, and aortic atheroma has been well described in recent years. Care must be exercised in using TEE to identify suspected cardiac sources of embolism, as potential etiologies described in the literature are not equally established by rigorous clinical trials. Confidence level in cause and effect for any cardiac pathology identified must be factored into therapeutic decisions.     

Use of echocardiography in detecting cardiac sources of embolus

Up to 20% of all ischemic strokes are felt to be the result of emboli from the heart. High resolution transthoracic (TTE) and transesophageal (TEE) echocardiography have been the principal diagnostic tools for detecting associated cardiac abnormalities and for guiding medical and surgical approaches to these patients. In addition to identifying the precise location and morphological characteristics of intracardiac masses, echocardiography has improved our ability to predict embolic potential of these masses. Specific cardiac lesions that are predisposed to stroke and are readily identifiable by echocardiography include: cardiac thrombi, valvular vegetations, cardiac tumors, aortic atheroma, atrial septal aneurysm, and regional left ventricular wall abnormalities. Careful interrogation of patients with cerebrovascular accidents has identified a potential cardiac source of embolus in approximately 30%. This is largely due to the advent of TEE, which has provided much better assessment of posterior cardiac chambers including left atrium and left atrial appendage. Use of TEE in identifying a cardiac source of embolus is indicated in patients with stroke who are young, have no apparent cerebrovascular disease, or have recurrent embolic events. Echocardiography is an essential diagnostic tool in evaluating patients with a suspected cardiac source of embolus. TTE and TEE provide invaluable information regarding the majority of cardiac sources of embolus.     

Left atrial volume determination by echocardiography

To validate echocardiographic left atrial volume measurements, 25 patients with mitral stenosis were studied before and after mitral balloon valvuloplasty. Seven normals served as controls. The modified Simpson's rule was used for echocardiographic and angiographic left atrial volume determination from two orthogonal planes. Left atrial antero-posterior diameter was measured from parasternal long axis view and supero-inferior and medio-lateral diameters from apical four-chamber view. Transthoracic echocardiographic left atrial volume correlated well, but systematically underestimated angiographic left atrial volume (y=0.4x+27, r=0.92). Monoplane transesophageal echocardiography did not improve correlation, nor the underestimation. Out of the several left atrial diameters, antero-posterior dimension showed the closest correlation with angiographic volume (r=0.91), which persisted after exclusion of patients with atria >400 ml (r=0.84). Futhermore, relative changes of antero-posterior diameter after mitral valvuloplasty were closely related to the relative changes observed in left atrial volume (r=0.82). Our results suggest that, in spite of a consistent underestimation, bidimensional, transthoracic echocardiographic and angiographic left atrial assessment correlate closely. Moreover, it is suggested that the mere antero-posterior diameter from transthoracic two-dimensional image is sufficient in clinical practice for routine follow-op of left atrial volume.     

Prominent para-cardiac fat mimicking left atrial appendage thrombus on echocardiography: Utility of cardiac computed tomography

Transesophageal echocardiography is the most frequently used imaging modality for exclusion of left atrial appendage thrombus prior to cardioversion. Echocardiographers should be aware of rare conditions that may mimic left atrial appendage thrombus. Here, we describe a rare case of prominent para-cardiac fat mimicking left atrial appendage thrombus on transesophageal echocardiographic imaging. Multimodality imaging with cardiac computed tomography was instrumental in providing further anatomical delineation and characterization of the echodensity as prominent para-cardiac fat in this case.     

Is Transesophageal Echocardiography Necessary before D.C. Cardioversion in Patients with a Normal Transthoracic Echocardiogram?

PURPOSE: Transesophageal echocardiography has emerged as an accepted approach before D.C. cardioversion for atrial fibrillation. The frequency of atrial thrombi detected on transesophageal echocardiography has varied from 7% to 23%. Many patients undergoing transesophageal echocardiography have had a previous transthoracic echocardiogram. Though transthoracic echocardiography has a low yield for the detection of intracardiac thrombi, it is highly accurate in diagnosing a structurally abnormal heart. The purpose of this study was to assess the frequency of thrombi detected by transesophageal echocardiography in patients with an entirely normal transthoracic echocardiogram and hence the advocacy of a selective approach in performing transesophageal echocardiography in patients undergoing D.C. cardioversion for atrial fibrillation. METHODS: 112 consecutive patients with atrial fibrillation who had undergone transesophageal echocardiography before D.C. cardioversion were evaluated. They all had a transthoracic echocardiogram within the 2 months preceding their transesophageal echocardiogram. Based on their transthoracic echocardiographic study, they were divided into two groups: Group 1 consisted of patients with a normal transthoracic echocardiogram and Group 2, those with an abnormal study. RESULTS: Thrombi or spontaneous echo contrast were found in 14 of 112 patients (16%). All however were detected in Group 2 patients. There was no patient with a normal transthoracic echocardiogram who had thrombus on his/her transesophageal echocardiogram. CONCLUSIONS: Our results suggest that a selective approach may be exercised in the use of transesophageal echocardiography prior to D.C. cardioversion for atrial fibrillation. Patients with an entirely "normal" transthoracic echocardiogram may proceed directly to cardioversion without a precardioversion transesophageal echocardiogram.     

Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus

Thrombi located in the left atrial appendage are frequently not detected with conventional two-dimensional echocardiography. The transesophageal echocardiographic approach readily visualizes left atrial morphology and may be used as an alternative. In 6 of 21 patients with mitral valve stenosis, a left atrial appendage thrombus was diagnosed by transesophageal two-dimensional echocardiography when transthoracic echocardiography had failed. The transesophageal echocardiographic findings were confirmed at surgery for mitral valve replacement in all cases.