Left Atrial Spontaneous Echo Contrast Research Articles

Effect of direct current shocks on left atrial mechanical function in patients with structural heart disease.

This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease. DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial "stunning" and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear. Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock. There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks. Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.

Rapid onset and dissipation of left atrial spontaneous echo contrast during percutaneous balloon mitral valvotomy

Background Thromboembolism after percutaneous balloon mitral valvotomy (PBMV) has been attributed to dislodement of preexisting thrombus during transseptal puncture and instrumentation of the left atrium. The occurrence of thromboembolic events after PBMV in the absence of demonstrable left atrial thrombus before PBMV suggests that thrombus might form during the procedure. Spontaneous echo contrast (SEC) is a swirling pattern of blood echogenicity that is a marker of blood stasis in the left atrium. Exacerbation of left atrial SEC during PBMV may be indicative of an increased thromboembolic risk. Methods Transesophageal echocardiography was performed during PBMV in 20 patients with mitral stenosis. Grades of severity of left atrial SEC [0 (nil) to 4+ (severe)] were allocated before and after each balloon inflation. Results Before PBMV, SEC was present in 17 patients. New SEC or increased severity of SEC was observed during 49 of 56 balloon inflations. SEC was unchanged after six deflations, decreased after 14 deflations, and disappeared after 36 deflations. The mean times to onset and dissipation of SEC after balloon inflation and deflation were 3.1 ± 1.5 and 3.9 ± 1.6 seconds, respectively. After successful PBMV, SEC was unchanged in three patients, decreased in one, and resolved in 13. Conclusions SEC is a dynamic and acutely reversible phenomenon that is highly sensitive to changes in left atrial hemodynamic conditions. Left atrial blood stasis induced by balloon inflation may promote thrombogenesis during PBMV. (Am Heart J 1998;135:609-13.)

Activation of Blood Coagulation in Patients With Mitral Stenosis and Sinus Rhythm

The aim of this study was to assess whether there is blood coagulation activation in patients with mitral stenosis (MS) and sinus rhythm (SR) and to investigate the value of left atrial spontaneous echo contrast (LASEC) as a predictive sign of increased coagulation activity. Using thrombin-antithrombin III complexes and prothrombin fragment 1+2 as in vivo hemostatic markers, we concluded that there is a hypercoagulable state in patients with MS and SR when LASEC is present.

Cardiovascular Death in Patients With Atrial Fibrillation Is Better Predicted by Left Atrial Thrombus and Spontaneous Echo Contrast as Compared to Clinical Parameters

Cardiovascular Death in Patients With Atrial Fibrillation Is Better Predicted by Left Atrial Thrombus and Spontaneous Echo Contrast as Compared to Clinical Parameters

Relationship between flow dynamics in the left atrium and hemostatic abnormalities in patients with nonvalvular atrial fibrillation.

To investigate the relationship between left atrial (LA) flow dynamics and hemostatic markers in nonvalvular atrial fibrillation (AF), 45 patients with nonvalvular AF who had not received anticoagulants were evaluated by transesophageal echocardiography. We determined the LA appendage flow and the presence of LA spontaneous echo contrast (SEC) or thrombus. We measured plasma levels of thrombin-antithrombin III complex (TAT), fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 in peripheral blood as hemostatic markers. The patients were divided into a low-velocity group (n = 19; sum of peak emptying and filling LA appendage flow velocities < 40 cm/s) and a high-velocity group (n = 26; > or = 40 cm/s). The maximum LA diameter was significantly greater and the LA expansion fraction was significantly smaller in the low-velocity group than in the high-velocity group. LA SEC or thrombus was observed in 11 patients (58%) in the low-velocity group, but not in any patients in the high-velocity group (p < 0.001). The plasma levels of TAT, fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 were significantly higher in the low-velocity group than in the high-velocity group. The plasma levels of TAT, fibrinopeptide A, beta-thromboglobulin, and platelet factor 4 were significantly higher in 8 patients without LA SEC or thrombus in the low-velocity group than in 26 patients in the high-velocity group. Patients with nonvalvular AF accompanied by an enlarged and dysfunctioning LA and a decreased LA appendage flow velocity had increased intravascular coagulation-fibrinolysis activity and platelet activation. These abnormalities may be closely related to the thrombogenetic state in patients with nonvalvular AF.

Cardiovascular death in patients with atrial fibrillation is better predicted by left atrial thrombus and spontaneous echo contrast as compared to clinical parameters

Cardiovascular death in patients with atrial fibrillation is better predicted by left atrial thrombus and spontaneous echo contrast as compared to clinical parameters

Natural History of Left Atrial Spontaneous Echo Contrast in Nonrheumatic Atrial Fibrillation

A prospective study was designed to investigate potential changes of left atrial (LA) spontaneous echo contrast with time and the effects of antithrombotic therapy on its presence in 77 patients with chronic nonrheumatic atrial fibrillation (AF), using serial transesophageal echocardiography (TEE). During a mean follow-up period of 20 ± 15 months (range 6 to 77), a total of 197 TEE studies were performed in these patients. Baseline TEE revealed that LA spontaneous echo contrast was absent in 43 patients (group 1) and present in 34 (group 2). LA thrombus was found in 8 of group 2 but in none of the group 1 patients. During the follow-up period, only 2 of the group 1 patients were receiving antithrombotic agents; the patients in group 2 without LA thrombus were treated with either warfarin or aspirin, whereas those with LA thrombus were treated with warfarin. On the latest TEE study, LA spontaneous echo contrast was observed in 19 of the group 1 patients (44%) and was persistently found in all of the group 2 patients. During the study period, no patient was found to develop new LA thrombus formation and only 4 episodes of transient ischemic attack were recorded in 4 patients (embolic event rate = 3.1% per year). Of these, 2 were observed in group 1 and the remaining 2 were from group 2 and under aspirin therapy (event rate = 2.2% and 4.7% per year, respectively). In the subgroup of patients with LA thrombus receiving warfarin therapy, follow-up TEE revealed complete resolution of the thrombi in 6 and partial resolution in the remaining 2 in spite of the persistence of LA spontaneous echo contrast; none of these patients developed clinical thromboembolic events during the study period. Thus, future occurrence of LA spontaneous echo contrast could be observed by serial TEE at a substantial rate in patients with nonrheumatic AF who have no LA spontaneous echo contrast; follow-up TEE should be recommended for these patients to detect early the potential occurrence of LA spontaneous echo contrast if preventive antithrombotic therapy is not considered. Although warfarin therapy is associated with resolution of LA thrombus, neither warfarin nor aspirin is effective for suppressing the presence of LA spontaneous echo contrast in nonrheumatic AF.

Conventional and total orthotopic cardiac transplantation: a comparative clinical and echocardiographical study.

Clinical interest has recently emerged in a new technique of heart transplantation with bicaval and pulmonary venous anastomosis. This technique is thought to improve left heart function and reduce thromboembolism. We have used this technique systematically since 1993. We compared the patients transplanted before September 1993 with the standard technique and the patients transplanted with the new technique. A total of 135 patients were transplanted at our institution from 1987 to 1995, 100 with the standard technique and 35 with the new technique. of these, 95 survivors were studied by transthoracic and transesophageal echocardiography; 65 were transplanted with the standard technique ('standard' group) and 30 with the new technique ('total heart' group). All patients were free from rejection and in sinus rhythm when studied. Boths groups were similar in pretransplant characteristics. Operative data were similar with a limited increase in the ischemic time with the total heart technique (210 +/- 73 min for 'total heart' vs. 196 +/- 84 min for 'standard'). Right heart catheterization showed comparable cardiac output and pulmonary pressures. Peripheral embolic events occured in 9 patients in the 'standard' group and none in the 'total heart' group. The left atrium was larger in the 'standard' group (58 +/- 6 vs. 42 +/- 4 mm, P = 0.0006). Left atrial spontaneous echo contrast was present in 32 patients in group 'standard' and none in 'total heart' group (P < 0.0001), and left atrial thrombi were detected in 17 patients in group 'standard' vs. none in group 'total heart' (P = 0.01). All patients with a history of embolism had left atrial thrombus and spontaneous echo contrast. This study showed a high incidence of left atrial spontaneous echo contrast and thrombi when using the standard technique, which was absent when using the total heart technique. Total heart transplantation with bicaval and pulmonary venous anastomosis should be preferred for heart transplantation.

Left atrial spontaneous echo contrast in patients with permanent pacemakers.

OBJECTIVE: To determine the relations between left atrial appendage function, spontaneous echo contrast, and thromboembolism in patients with different modes of permanent pacemakers. PATIENTS AND METHODS: 88 patients with pacemaker...

Congenital mitral stenosis: challenge of percutaneous transvenous mitral commissurotomy

A 26-year-old woman with congenital mitral stenosis and embolic stroke was referred to our hospital. The echocardiogram showed a hypoplastic posterior mitral valve leaflet with short, unbalanced chordal attachments to the posteromedial papillary muscle. The mitral valve area was 0.9 cm 2 by the pressure half-time method. There was no left atrial thrombus and spontaneous echo contrast. Percutaneous transvenous mitral commissurotomy was performed since the suggestion of surgical management was refused by her family members. A rupture at the chordae tendinae of the hypoplastic posterior papillary muscle developed during the procedure and needed mitral replacement. We advise that percutaneous transvenous mitral commissurotomy be avoided in adult patients with congenital mitral stenosis having an asymmetric and hypoplastic mitral valve.

Haemostatic and haemodynamic abnormalities associated with left atrial thrombosis in non-rheumatic atrial fibrillation.

OBJECTIVE: To evaluate the role of haemostatic and haemodynamic variables in left atrial thrombosis in non-rheumatic atrial fibrillation. DESIGN: Case-control study. SUBJECTS: One hundred and nine patients with non-rheumatic atrial...

Platelet Activation in Embolic and Preembolic Status of Patients With Nonrheumatic Atrial Fibrillation

Information on platelet activation possibly associated with a preembolic or embolic status in nonrheumatic atrial fibrillation (AF) with special regard to the role of platelet membrane activation markers (P-selectin and CD63). The study included 60 patients with nonrheumatic AF; 28 of them had a history of an embolic event. The age-matched control group consisted of 28 healthy subjects (13 men and 15 women). Patients underwent transesophageal echocardiography to detect eventual intracardiac thrombus or spontaneous echo contrast that would represent a preembolic status. Blood samples were taken from all persons to evaluate markers for platelet activation under these conditions. Measurements of hematologic variables did not differ significantly between normal subjects and patients presenting with AF but no preembolic or embolic status. Elevated concentrations of fibrinogen were significantly related to the presence of left atrial spontaneous echo contrast. The amount of circulating platelets expressing P-selectin and CD63 was significantly higher in the patients positive for both spontaneous echo contrast and left atrial thrombus or embolic events. Furthermore, in these groups, significantly more leukocyte-platelet conjugates were present. Platelet activation indicated by platelet membrane activation markers occurs in embolic and preembolic status of patients with nonrheumatic AF.

Stability of Left Atrial Spontaneous Echo Contrast at Repeat Transesophageal Echocardiography in Patients With Mitral Stenosis

We evaluated the stability of left atrial spontaneous echo contrast in 25 patients with mitral stenosis who underwent repeat transesophageal echocardiography over periods ranging from 1 month to 3 years. Left atrial spontaneous echo contrast did not disappear or decrease in severity in any patient and was unchanged in 88% of patients.

Effect of Warfarin on Regional Left Atrial Coagulation Activity in Mitral Stenosis

Increased regional left atrial (LA) coagulation activity has recently been implicated in the pathophysiology of LA thrombus and systemic embolism in mitral stenosis (MS). Anticoagulation with warfarin reduces the risk of such thromboembolism, but the effect of warfarin on LA coagulation activity is unknown. We have addressed this question in MS patients with normal or prolonged clotting times. Peripheral venous and LA coagulation activities were measured in MS patients on long-term oral anticoagulation, who were predisposed to increased LA coagulation activity because of the presence of LA spontaneous echo contrast. Patients ceased warfarin 4 days before percutaneous balloon mitral valvuloplasty, and had either a normal (n = 15) or prolonged (n = 8) International Normalized Ratio (INR) at valvuloplasty. Coagulation activity was assessed during the valvuloplasty procedure, but before valve dilation, by measuring levels of prothrombin fragment 1 +2 (F1 + 2), a marker of thrombin generation. The LA F1 + 2 level exceeded the peripheral venous level in patients with a normal INR (p <0.001), but these levels were similar in patients with a prolonged INR (p = 0.16). Moreover, the LA (p <0.005) and peripheral venous (p <0.03) F1 + 2 levels, as well as the LA-peripheral venous F1 + 2 difference (p <0.03) were lower in patients with a prolonged INR. These results suggest that anticoagulation with warfarin in MS not only reduces systemic coagulation activity but is associated with a greater reduction in LA coagulation activity. The latter may contribute to the reduced risk of LA thrombus formation that accompanies warfarin therapy in MS.

Prevalence and clinical significance of left atrial thrombus in nonrheumatic atrial fibrillation

The prevalence and clinical significance of left atrial thrombus were prospectively investigated in a consecutive series of 219 patients with chronic nonrheumatic atrial fibrillation using transesophageal echocardiography. Fifteen left atrial thrombi were detected in 15 of the 219 patients (6.8%); 12 of these thrombi (80%) were confined to the left atrial appendage. Left atrial spontaneous echo contrast was visualized in 85 patients (39%). All the thrombi were found in the left atria with spontaneous echo contrast. Patients with left atrial thrombus had significantly lower left ventricular ejection fraction than those without (49±14% vs. 59±14%; P<0.05). Multivariate analysis among clinical and transthoracic echocardiographic variables showed that left ventricular ejection fraction <50% was the only independent predictor for the presence of left atrial thrombus. A history of thromboembolism was significantly more frequent in patients with left atrial thrombus than in those without (73% vs. 32%; P<0.005). The presence of left atrial thrombus was more specific than spontaneous echo contrast for predicting history of thromboembolism (97% vs. 80%), but its sensitivity was significantly lower (14% vs. 73%). We conclude that: (1) Transesophageal echo-detected left atrial thrombus is not uncommon in patients with chronic nonrheumatic atrial fibrillation and is exclusively observed in those with left atrial spontaneous echo contrast. (2) Impaired left ventricular systolic function may predispose the left atrial thrombus formation. (3) Left atrial thrombus is a highly specific but insensitive predictor for thromboembolic events.

Transesophageal Echocardiography in Various Ischemic Stroke Subtypes.

Transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) in detecting the potential source of emboli in cardioembolic strokes (CES). To establish the prevalence of a potential cardiac source of embolism detectable on TEE and its relationship to vascular risk factors, an unselected ischemic stroke population was evaluated. Twenty-six age and sex-matched cases with normal cardiological and neurological examinations as well as normal CT-scans, TTE and ECGs were included in the study as the control group. One hundred and eight patients with cardioembolic stroke (53 patients), atherothrombotic stroke (36 patients), and lacunar stroke (19 patients) were investigated by TTE and TEE. Seven of the 26 (26.9%) controls had thoracic atherosclerotic plaques on TEE examinations. The prevalence of abnormal TEE findings in patients was higher compared to the controls (p < 0.001). TEE revealed more specific findings in every etiological group when compared to TTE (74.0% vs 10.2%, p < 0.001). Atrial fibrillation correlated with the abnormalities of TEE (p < 0.05) while other risk factors did not. Left atrial spontaneous echo contrast was the most common finding on TEE of cases with cardioembolic stroke while atherosclerotic aortic plaques were mostly encountered in patients with atherothrombotic stroke. No specific findings by TEE were seen in patients with lacunar stroke. TEE is capable of detecting definite etiologies in cardioembolic stroke and associated cardiac pathologies in atherothrombotic stroke and lacunar stroke. These observations suggest that TEE is a useful tool to guide the physician for the treatment of ischemic stroke patients.

Direct effects of DC cardioversion on blood echogenicity: An in vitro study

Exacerbation of left atrial spontaneous echo contrast (SEC) after cardioversion of atrial fibrillation has been attributed to left atrial mechanical dysfunction induced by the procedure (“atrial stunning”). An in vitro model was devised to determine whether electrically induced changes in blood properties might contribute to SEC formation after cardioversion. Human blood echogenicity was examined quantitatively by videodensitometry before and after shocks of 1, 2, 5, and 20 J. Changes in blood cell numbers, cell morphology, and erythrocyte sedimentation rate were determined by haematological analysis. Immediately following electrical discharges, transient and dose-related, highly echogenic microbubbles were noted, but shocks of increasing intensity did not induce SEC at high blood velocity or alter the severity of SEC at low blood velocity. No quantitative or qualitative changes in haematological parameters were observed. These results suggest that direct effects of electrical shock on blood do not contribute to SEC after cardioversion. Systemic haematological responses to electric shock that might indirectly promote red cell aggregation in vivo cannot be excluded by this in vitro study.

Left Atrial Spontaneous Echo Contrast in Asymptomatic Patients With a Mechanical Valve Prosthesis

Background. Valve thromboembolism may be a fatal complication of mechanical valve prosthesis if detected late. Spontaneous echo contrast (SEC) is a well-documented prothrombotic phenomenon; here we report it in asymptomatic patients with a mechanical valve prosthesis. Methods. Ninety-two asymptomatic patients with a mechanical valve prosthesis for underlying rheumatic heart disease underwent transesophageal echocardiography. Appendage area, peak filling and emptying velocities of the left atrial appendage, and the presence or absence of SEC and thrombi were determined. The results of 56 patients without SEC or thrombi (group I) were compared with those of 24 patients with SEC and no thrombi (group II) and 12 patients with thrombi (group III). Results. Spontaneous echo contrast was present in 39% of the asymptomatic patients with a mechanical valve prosthesis. Although 12 patients had cardiac thrombi, including valve thrombi in 4, no patients presented symptoms. Anticoagulant therapy had no significant association with SEC and atrial thrombi. There was a significantly greater prevalence of atrial fibrillation and mitral prosthesis in groups II and III than in group I. Two patterns of left atrial appendage flow were identified: one was organized biphasic flow with peak filling velocities of 41.2 ± 17.2 cm/s and emptying velocities of 40.5 ± 17.5 cm/s. The other showed irregular, very low peak filling velocities (10.4 ± 11.5 cm/s) and emptying velocities (12.3 ± 13.1 cm/s). The former flow pattern was associated with sinus rhythm and the latter form was associated with atrial fibrillation. Conclusions. There was a relatively high prevalence of SEC and thrombi in patients with a mechanical valve prosthesis. Patients with a valve prosthesis may not have clinical symptoms. Anticoagulation intensity was not associated with the occurrence of SEC and thrombi. Patients with a mitral valve prosthesis and atrial fibrilation were identified as a high-risk of subgroup for the development of SEC and thrombi.

Evaluation of left atrial appendage anatomy and function in recent-onset atrial fibrillation by transesophageal echocardiography

Data regarding left atrial (LA) and LA appendage anatomy and function among patients with newly recognized atrial fibrillation (AF) who have not received longterm warfarin are currently unknown. To identify echocardiographic indexes which characterize those at increased risk for thrombus formation, we analyzed transesophageal echocardiographic studies in 100 consecutive patients with newly recognized AF (duration 2.6 ± 0.3 week) who had not received long-term warfarin. Fourteen percent of patients had LA thrombi. LA thrombi were associated with larger LA appendages, more depressed LA appendage outflow velocities, and a higher prevalence of severe spontaneous LA contrast. Patients with spontaneous contrast had larger LA and LA appendage anatomy and lower LA appendage ejection velocity. Among patients presenting with their first episode of AF, greater LA appendage ejection and filling velocities and smaller LA and LA appendage sizes were seen among those with AF of <2 weeks duration compared with those with AF of >2 weeks. Thus, patients with recent onset AF and LA thrombi or spontaneous echo contrast have more dilated LA and LA appendage anatomy, and more depressed LA appendage systolic function. Data from patients with their first episode of AF suggests that AF is associated with rapid LA remodeling.

Determinants of increased regional left atrial coagulation activity in patients with mitral stenosis.

Recent evidence suggests that regional left atrial coagulation activity may be increased in mitral stenosis and perhaps contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown, and the relation between left atrial and systemic coagulation activities is unresolved. Left atrial and peripheral venous levels of the coagulation marker prothrombin fragment 1 + 2 (F1 + 2) were measured in 32 patients with mitral stenosis with normal clotting times and no left atrial thrombus who were undergoing percutaneous balloon mitral valvuloplasty. Baseline peripheral venous F1 + 2 levels, measured at the beginning of the valvuloplasty procedure, did not differ from those of 30 age-matched control patients. Prevalvuloplasty left atrial F1 + 2 levels, obtained immediately after transseptal puncture, were similar to femoral venous levels in patients without left atrial spontaneous echo contrast (LASEC) (0.81 +/- 0.32 versus 0.81 +/- 0.27 nmol/L, n = 7) but greater than femoral venous levels in patients with LASEC and either sinus rhythm (1.57 +/- 0.86 versus 0.99 +/- 0.38 nmol/L, n = 16, P < .001) or atrial fibrillation (1.52 +/- 0.69 versus 0.85 +/- 0.33 nmol/L, n = 9, P < .003). Furthermore, LASEC emerged as the only significant predictor of increased regional left atrial coagulation activity (P = .005) on stepwise multivariate logistic regression analysis. Increased regional left atrial coagulation activity in mitral stenosis occurs in the presence of LASEC, is evident in either sinus rhythm or atrial fibrillation, and is associated with normal systemic coagulation activity.