Left Atrial Appendage Dysfunction Research Articles

Low Wall Velocity of Left Atrial Appendage Measured by Trans-Thoracic Echocardiography Predicts Thrombus Formation Caused by Atrial Appendage Dysfunction

Atrial fibrillation is associated with ischemic stroke because of thrombi that form within the left atrial appendage (LAA). The aim of this study was to develop a new parameter for LAA function that is easily performed using transthoracic echocardiography (TTE). TTE and transesophageal echocardiography were performed in 106 patients with stroke. LAA wall motion velocity (TTE-LAWV) was measured using Doppler tissue imaging at the LAA tip. TTE-LAWV was significantly lower in patients with atrial fibrillation and LAA thrombus than in those with atrial fibrillation and no LAA thrombus and in sinus rhythm (7.5 +/- 1.9 vs 10.0 +/- 3.4 and 13.8 +/- 5.7 cm/s, respectively, P < .05). TTE-LAWV was significantly correlated with LAA emptying flow velocity (R = 0.462, P < .05). The multivariate logistic regression analysis showed that TTE-LAWV < 8.7 cm/s was an independent predictor of LAA thrombus formation (odds ratio, 9.473; 95% confidence interval, 1.172-76.55; P < .05). TTE-LAWV can noninvasively evaluate LAA dysfunction and assist in the detection of LAA thrombus.

Abstract 5125: Elevated Serum Brain Natriuretic Peptide Level Predicts the Presence of the Left Atrial Appendage Dysfunction in Patients With Acute Ischemic Stroke

Background: It is well known that the left atrial appendage (LAA) dysfunction plays an important role in the occurrence of the cardioembolic stroke. It has been reported that the atrium is the main source of brain natriuretic peptide (BNP) in atrial fibrillation patients without heart failure. Therefore, we hypothesized that serum BNP levels are sensitive predictor for LAA dysfunction and thrombus formation in patients with acute ischemic stroke. Methods: We performed trans-thoracic and esophageal echocardiography within 7 days after the onset (male, n=64, 69±11 years old; female, n=38, 68±15 years old) and measured serum hemostatic markers and BNP in 103 patients with ischemic stroke. No patients had history of heart failure. Results: LAA thrombus was detected in 8 patients (36%) among 22 patients with atrial fibrillation. Even in 3 patients (4%) among 80 patients with sinus rhythm, LAA thrombus was detected. There were no significant differences in left ventricular end-diastolic dimension (LVDd), and the ratio of the early diastolic trans-mitral inflow velocity (E) to mitral annular velocity (E′) between patients with and without LAA thrombus (LVDd, 49±6 vs. 47±5 mm; E/E′, 8.6±1.3 vs. 7.2±0.9). Serum BNP levels were markedly higher in patients with LAA thrombus formation than in those without it (191 (128 –278) vs. 39 (13–100) pg/ml, P&lt;0.01). Furthermore, in patients with sinus rhythm (n=80), the BNP levels were significantly correlated with LAA peak emptying flow velocity (R=−0.34, P&lt;0.01). The multivariate logistic regression analysis revealed that BNP &gt;120 was an independent predictor of LAA thrombus formation (odds ratio, 13.50; 95% confidence interval, 2.482–73.40; P=0.0026). Conclusions: The BNP levels were correlated with LAA peak emptying flow velocity. The elevated BNP level could be used as a non-invasive surrogate maker to predict LAA dysfunction and thrombus formation in patients with acute ischemic stroke.

Abstract 5127: Left Atrial Ejection Fraction (LAEF) is a Novel Marker of Left Atrial Appendage Dysfunction in Acute Stroke Patients

Background Recently, it was reported that left atrial ejection fraction (LAEF) may be as a marker of left atrial dysfunction. However, the feasibility of LAEF remains to be determined. We investigated whether LAEF is a marker of left atrial appendage (LAA) dysfunction which causes cardiogenic embolism in stroke patients. Methods We performed trans-thoracic echocardiography (TTE) and trans-esophageal echocardiography (TEE) in 53 consecutive stroke patients (cardiogenic embolism, male/female=14/9, 70±12y; stroke of other sources, male/female =21/9, 66±16y). LAEF was calculated by the biplane area-length method from apical 4- and 2-chamber views at end systolic and diastolic phase. We compared LAEF to LAA peak emptying flow velocity which is an established marker of LAA dysfunction. Results LAEF was significantly lower in patients with cardiogenic embolism than in those without it (LAEF, 30.4±11.0 vs. 45.4±14.7, P&lt;0.01). Left atrial dimensions, time and the ratio of the early diastolic trans-mitral inflow velocity (E wave), left atrial volume index (LAVI) and LAEF were significantly correlated with LAA emptying flow velocity. However, only LAEF was significantly correlated with LAA emptying flow velocity in patients with atrial fibrillation (R=0.566, p&lt;0.05). Furthermore, the multivariate logistic regression analysis revealed that only LAEF was an independent predictor of LAA dysfunction in TTE parameters (odds ratio 3.96; 95% confidence interval 1.02–15.27; P&lt;0.05). Conclusions LAEF may be a reliable non-invasive maker of LAA dysfunction and predict cardiogenic embolism in stroke patients.

Abstract 2645: Low Wall Motion Velocity of Left Atrial Appendage Predicts Thrombus Formation Caused by Atrial Appendage Dysfunction in Acute Stroke Patients with Atrial Fibrillation

It is well established that transesophageal echocardiography (TEE) is the most useful examination to detect thromboembolic sources in acute stroke patients, in spite of semi-invasive procedure. Transthoracic echocardiography (TTE) is less invasive, whereas it is sometimes difficult to detect thrombus in left atrial appendage (LAA). The aim of this study was to elucidate whether LAA wall motion measured by TTE was useful for detecting LAA thrombus. We performed TTE and TEE in 169 consecutive acute ischemic stroke patients with AF within 7 days after the onset (male, n=117, 71 ± 11 years old; female, n=52, 75 ± 10 years old). LAA wall motion velocity (LAWV) was measured by tissue Doppler imaging at LAA tip from parasternal short axis view of TTE. Patients were prospectively followed-up until primary endpoints such as stroke recurrence or death (mean follow-up period of 362 days). LAWV was significantly lower in patients with LAA thrombus than in those without thrombus (8.1 ± 1.9 vs. 11.6 ± 4.1 cm/s, P&lt;0.01). LAWV was significantly correlated with LAA peak emptying flow velocity (R=0.74, P&lt;0.01). The multivariate logistic regression analysis showed that low LAWV (&lt;9.3 cm/s) was an independent predictor of LAA thrombus formation (odds ratio, 16.45; 95% confidence interval, 4.57–59.25; P&lt;0.01). Stroke recurrence occurred in 24 patients (14%) during follow-up. The Cox multivariate proportional hazard analysis revealed that low LAWV (&lt;9.3 cm/s) was an independent predictor for stroke recurrence (hazard ratio, 5.0; 95% confidence interval, 1.14 –21.74; P&lt;0.05). Kaplan-Meier survival analysis showed that stroke recurrence rates were markedly higher in patients with low LAWV than in those with high LAWV (26% vs. 6%, P&lt;0.01). In conclusion, LAWV successfully detected LAA dysfunction which caused LAA thrombus. Low LAWV may be a non-invasive predictor for stroke recurrence in ischemic stroke patients.

Post-cardioversion transesophageal echocardiography (POSTEC) strategy with the use of enoxaparin for brief anticoagulation in atrial fibrillation patients: the multicenter POSTEC trial (a pilot study)

In patients with atrial fibrillation (AF), we sought to evaluate the feasibility and safety of a new transesophageal echocardiography (TEE)-guided strategy, aimed at selecting, 7 days post-cardioversion, those patients who are at low risk (i.e. who can terminate anticoagulation after a second TEE) and those at high risk (i.e. who have to continue it). We enrolled 206 patients with non-valvular AF into a randomized, multicenter clinical trial. Group A patients underwent a TEE-guided cardioversion with heparin and at least 4 weeks of oral anticoagulation therapy (OAT) after cardioversion. Group B patients received enoxaparin and underwent a TEE-guided cardioversion. After 7 days, a second TEE was carried out. In the absence of TEE thromboembolic risk factors and left atrial appendage (LAA) dysfunction anticoagulation was discontinued. In group A, 88 out of 102 patients underwent TEE and cardioversion was efficacious in 77 of 78. In group B, 100 out of 104 patients underwent TEE and cardioversion was efficacious in 80 of 87 patients; 55 patients underwent the second TEE and enoxaparin was stopped in 50 without LAA dysfunction. In group A, one transient ischemic attack and one sudden cardiac death occurred. In group B, one patient with complex aortic plaques suffered a stroke during enoxaparin. There was a minor hemorrhage in groups A and B, and a severe hemorrhage in a patient during OAT because of persistent atrial stunning. Hospitalization length and duration of anticoagulation were significantly shorter in group B. The pre/post-cardioversion TEE strategy with enoxaparin in AF may constitute a feasible and safe approach in selecting patients at low thromboembolic risk who can benefit from precocious termination of anticoagulation (7 days after cardioversion). It may be also useful to identify those patients in whom a life-lasting anticoagulation could be beneficial. A larger trial to confirm these findings is under way.

Abstract 2787: Elevated Circulating Levels Of Platelet-derived Microparticles Are Associated With The Thrombus Formation In The Left Atrial Appendage In Patients With Ischemic Stroke That Is Resistant To Anti-coagulant Therapies

Introduction: It is well known that elevation of fibrinolytic markers reflects thrombus formation in the left atrial appendage (LAA) that is identified as a fibrin-rich thrombus. On the other hand, it is sometimes difficult to remove LAA thrombus by the treatment of anti-coagulants alone. Hypothesis: Circulating platelet activation is also responsible for the thrombus formation in the LAA in patients with cardioembolic stroke. Methods: In 98 consecutive patients with cerebral infarction (mean age, 71±12 years old), we performed trans-esophageal echocardiography within 7 days after the onset, and at the same time, measured circulating platelet-derived microparticles (PDMP, as a marker of platelet activation, &lt; 20 U/ml), and serum levels of D-dimer (DD, as a marker of fibrinolytic activity, normal level &lt; 1.0 μg/ml). Patients with LAA peak emptying flow velocity &lt; 20 cm/s were classified as having LAA dysfunction. Results: In patients without warfarin treatment, both PDMP and DD levels were significantly higher in LAA thrombus positive (n=12) than in negative group (n=70) (PDMP, 113.5±80.4 vs. 65.5±30.7 U/ml, P&lt;0.001; DD, 7.3±10.4 vs. 2.9±3.7 μg/ml, p &lt; 0.01). In patients with warfarin treatment (PT-INR 1.64±0.35), PDMP, but not DD levels, was markedly higher in LAA thrombus positive (n=6) than in negative group (n=10) (PDMP, 113.4±84.5 vs. 49.7±23.9 U/ml, P&lt;0.05; DD, 2.1±1.8 vs. 1.6±1.3 μg/ml, NS), because DD were effectively suppressed by the anti-coagulant therapy. Furthermore, in LAA thrombus negative patients, there were no significant differences in PDMP between cases with and without LAA dysfunction (LAA dysfunction, n=13, 70.2±26.5 vs. No dysfunction, n=67, 63.3±31.1 U/ml). Conclusions : PDMP plays an important role in the LAA thrombus formation that is resistant to anti-coagulant treatment, and may be a useful predictor for the cardioembolic stroke occurrence.

Systolic Tissue Velocity Is a Useful Echocardiographic Parameter in Assessment of Left Atrial Appendage Function in Patients with Mitral Stenosis

The incidence of thromboembolism remains high in patients with mitral stenosis (MS). The left atrial appendage (LAA) is a potential site for development of thrombus and LAA dysfunction is an independent predictor of thromboembolism. The LAA dysfunction is represented by reduced LAA late emptying velocity. But the magnitude of LAA flow velocities is dependent on acute changes in loading conditions. To investigate the value of the LAA tissue velocities obtained by tissue Doppler imaging (TDI) in assessment of LAA function in MS patients with and without thromboembolic events. The study population consisted of 98 isolated MS patients of 32 age and sex-matched healthy controls. All subjects underwent transesophageal echocardiography (TEE). LAA late peak emptying (LAAEV) and filling (LAAFV) flow velocities were recorded. LAA peak late tissue systolic (LSV) and diastolic (LDV) tissue velocities by TDI were measured. The patients were divided into three groups as Group I (n = 38, sinus rhythm and LAAEV > or = 25 cm/s), Group II (n = 26, sinus rhythm and LAAEV < 25 cm/s), and Group III (n = 34, atrial fibrillation). Twenty-one patients had thromboembolic events. LAAEV, LAAFV, LSV, and LDV were significantly reduced in patients with embolic events. Spontaneous echo contrast (SEC) density was strongly negative correlated with LSV, whereas weakly negative correlated with LAAEV. Multivariate regression analysis showed that LSV and the presence of SEC were independently associated with embolic events. LSV seems more reliable and useful parameter in evaluating LAA function. LAA function is more depressed among patients with embolic events.

Antithrombotic therapy in atrial fibrillation: beyond the AFFIRM study

In the last few decades several clinical studies evaluated the efficacy and safety of different strategies for antithrombotic prophylaxis to prevent thromboembolic events in patients with atrial fibrillation (AF). Nowadays, a frequently debated point is related to the high embolic risk deriving from the asymptomatic and symptomatic AF recurrence after cardioversion or in paroxysmal AF, especially in patients with a large number of prolonged episodes of AF. In fact, after the recent AFFIRM and RACE trials, patients after successful cardioversion at risk for thromboembolism could also need lifelong anticoagulation. Considering this, should we anticoagulate all patients with clinical risk factors for thromboembolism with a single episode of AF, without considering the hemorrhagic risk? Based on recent trials, it is reasonable to hypothesize that long AF recurrences (> 48 h), both symptomatic and asymptomatic, are present mostly (if not exclusively) in patients with structural left atrial appendage (LAA) dysfunction and remodeling. Conversely, AF recurrences in patients without LAA dysfunction and remodeling, could be too short to allow thrombi formation in the LAA, and the anticoagulation could also be avoided. Once other clinical and echocardiographic determinants of stroke have been excluded, the LAA velocity could select patients with a normal appendage function at low embolic risk who could benefit from anti-aggregation and patients with irreversible appendage dysfunction, at high embolic risk, who need lifelong anticoagulation.

Mitral Annular Systolic Velocity Reflects the Left Atrial Appendage Function in Mitral Stenosis

Left atrial appendage (LAA) dysfunction is an independent predictor of thromboembolism in mitral stenosis (MS). To investigate whether there is a relation between annular velocities obtained by tissue Doppler imaging and LAA function and to determine if the annular velocities can predict the presence of the inactive LAA in MS. Eighty-five MS patients and 80 healthy controls were evaluated by transthoracic echocardiography and all patients underwent transesophageal echocardiography. The annular systolic (S-wave) and diastolic (E- and A-waves) velocities were recorded. Inactive LAA was defined as LAA emptying velocity <25 cm/sec. Patients were divided into three groups; group I (n = 43): sinus rhythm (SR) and LAA emptying velocity > or =25 cm/sec, group II (n = 15): SR and LAA emptying velocity <25 cm/sec and group III (n = 27): atrial fibrillation. Thrombus was detected in 12 patients and spontaneous echo contrast (SEC) was detected in 48 patients. Both S-wave and peak LAA emptying velocities were decreasing, while SEC frequency and density were increasing from group I to group III. There was a positive correlation between LAA emptying and S-wave velocities (P < 0.001, r = 0.682). Multivariate regression analysis showed that only S-wave is the independent predictor of inactive LAA (P = 0.001, odds ratio = 0.143, 95% CI = 0.047-0.434). In patients with SR, the cutoff value of S-wave was 13.5 cm/sec for the prediction of the presence of inactive LAA (sensitivity: 95.3%, specificity: 93.3%). S-wave is an independent predictor of inactive LAA and a useful parameter in estimating inactive LAA in MS with SR.

Transthoracic Echocardiographic Predictors of the Left Atrial Appendage Contraction Velocity in Stroke Patients with Sinus Rhythm

Systemic embolization is a potential complication in patients with thrombi situated in the left atrium and particularly, in the left atrial appendage (LAA). Reduced LAA contraction velocities, determined by the transesophageal echocardiography (TEE), are associated with increased risk of LAA spontaneous echocontrast and thrombus formation, and a history of systemic embolism. However, TEE remains a semi-invasive procedure, limiting its serial application as a screening tool. Therefore, it is desirable to obtain information regarding LAA function by transthoracic echocardiography in patients having cardioembolic stroke. The present study was designed to investigate various echocardiographic variables for patients with stroke to predict LAA dysfunction, reflected as reduced LAA contraction velocity. We studied a total of 61 patients with newly diagnosed acute embolic stroke (42 patients) and transient ischemic attack (19 patients). Computerized tomographic scanning was performed for the diagnosis of embolic stroke. Left atrial functional parameters determined by transthoracic echocardiography, such as left atrial active emptying fraction and acceleration slope of mitral inflow A wave, had significant correlations with the LAA contraction velocity (r = 0.57, p < 0.001; r = 0.54, p < 0.001, respectively). Left atrial volume index, left atrial active emptying volume and left atrial fractional shortening were also correlated with LAA contraction velocity (r = -0.44, p < 0.001; r = 0.38, p = 0.003; r = 0.37, p = 0.004, respectively). In conclusion, transthoracic echocardiography can provide valuable and reliable information about the LAA contraction velocity in stroke patients with sinus rhythm. This finding gives new insights for the appropriate strategy in the evaluation of an acute ischemic stroke.

The Left Atrial Appendage, a Small, Blind-Ended Structure: A Review of Its Echocardiographic Evaluation and Its Clinical Role

The increasing prevalence of stroke and atrial fibrillation is a stimulus for new therapeutic strategies and also warrants a review of imaging modalities of the most important source of cardiac systemic embolic events: the left atrial appendage (LAA). This blind-ended, complex structure is embryologically distinct from the body of the left atrium and is sometimes regarded as just a minor extension of the atrium. However, it should routinely be analyzed as part of a transesophageal echocardiographic (TEE) examination. A pulsed Doppler TEE analysis of LAA emptying flow should supplement a two-dimensional (2-D) analysis; these examinations have proven to be highly reproducible and to help assess thromboembolic risk. In 2-D imaging, potential thrombus and spontaneous echo contrast should be sought. In addition, LAA plays a hemodynamic role that participates in atrial function and is influenced by various hemodynamic conditions. In view of the embolic risks from a dysfunctional appendage, the LAA is often ligated during cardiac valve surgery. New devices are under evaluation for percutaneous closure of the LAA, and further studies should improve the definition, understanding, and treatment of LAA dysfunction.

Evaluation of left atrial appendage functions in patients with thrombus and spontaneous echo contrast in left atrial appendage by using color Doppler tissue imaging.

Thrombus and spontaneous echo contrast (SEC) develops in the left atrial appendage (LAA) when LAA function is disturbed. Decrease of left atrial appendage emptying velocity shows LAA dysfunction. The purpose of this study is to examine the incidence of SEC and/or thrombus in LAA in patients with acute myocardial infarction and to assess the LAA function using color Doppler tissue imaging (CDTI) of the patients with detected SEC and/or thrombus. Eighty-four patients with acute myocardial infarction were included in the study. Spontaneous echo contrast and/or thrombus were observed in 24 (29%) of the 84 patients who were categorized as group 1 (mean age 59 +/- 12 years). Sixty patients (71%) without thrombus and/or SEC in LAA were categorized as group 2 (mean age 58 +/- 8 years). Left atrial diameters and left ventricular ejection fraction were measured by using transthoracic echocardiography. Left atrial appendage emptying and LAA filling velocity were measured by transesophageal Doppler echocardiography. Systolic appendage tissue velocities (SaV cm/s) were measured at the basal, mid, and tip of medial wall of LAA by transesophageal CDTI. Group 1 had significantly decreased LAA emptying velocities, mid SaVs, and left ventricular ejection fractions compared to group 2 (37 +/- 9 cm/s vs 55 +/- 22 cm/s, 3.1 +/- 1.6 cm/s vs 3.7 +/- 1.2 cm/s, and 47 +/- 13% vs 58 +/- 10%, respectively, P = 0.002, P = 0.04, P = 0.03). Group 1 had significantly increased left atrial diameters compared to group 2 (40 +/- 5 mm vs 36 +/- 6 mm P = 0.001). Left atrial appendage-filling velocities, basal SaVs and tip SaVs in group 1 were lower than those in group 2 but not significantly. Mid-SaV of LAA medial wall and LAA emptying velocity decrease in patients with thrombus and/or SEC were an indication of functional disorder of LAA. Color Doppler tissue imaging appears to be a clinically applicable and reliable imaging technique that allows quantitative assessment of regional LAA systolic function.

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

Background In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation. Methods One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C. Results Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE. Conclusions A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.

Clinical and echocardiographic predictors of left atrial appendage dysfunction in patients with mitral stenosis in sinus rhythm

Background Mitral stenosis (MS) causes left atrial (LA) appendage (LAA) dysfunction resulting in reduced LAA flow velocities. Low LAA peak emptying velocity (PEV), determined by transesophageal echocardiography, is a risk for thrombus formation and systemic embolism. Objective We sought to investigate various clinical and echocardiographic predictors of low LAA blood flow velocities. Methods A total of 44 patients with newly diagnosed MS were classified into two groups on the basis of the presence of high (PEV ≥ 46 cm/s) or low (PEV < 46 cm/s) LAA flow profile on Doppler transesophageal echocardiography. LAA flow velocities were measured to be 27.38 ± 8.17 cm/s in patients with LAA dysfunction and 70.75 ± 16.71 cm/s in high-flow profile ( P < .0001). Simultaneous 12-lead electrocardiogram was used to measure P waves. Results P maximum, P dispersion, and LA diameter were significantly higher in patients with low LAA PEV (n = 32) than in those with high LAA PEV (111.87 ± 16.93 vs 96.66 ± 14.97, P = .0084; 73.12 ± 20.7 vs 49.16 ± 9.96, P < .0001; 46.06 ± 4.384 vs 38.08 ± 7.42 mm, P = .004; respectively). Patients with MS and low LAA blood flow had smaller mitral valve area compared with those with high LAA blood flow velocity (1.48 ± 0.431 vs 1.85 ± 0.442 cm 2, P = .02). Male sex, spontaneous echocontrast, and thrombus were more frequent in patients with low LAA PEV {7 [21.87%] vs 5 [41.66%], P = .026; 21 [65.62%] vs 4 [33.3%], P = .088; 4 [12.5%] vs none; respectively}. Mild MS was more frequent in patients with high blood flow velocity {6 [27.2%] vs 14 [63.6%], P = .03}. Conclusion At linear regression analysis, only P-wave dispersion and LA diameter predicted the LAA mechanical dysfunction reflected as low LAA PEVs.

Color Doppler tissue imaging to evaluate left atrial appendage function in patients with mitral stenosis in sinus rhythm.

Two-dimensional color Doppler tissue imaging (CDTI) has so far been used, in general, to evaluate ventricular function. In this study, the left atrial appendage (LAA) tissue velocity was measured by CDTI. LAA function in 38 patients with mitral stenosis in sinus rhythm (SR) and 19 healthy subjects undergoing transesophageal echocardiography were examined by CDTI. Systolic tissue appendage velocity (SaV, m/s) was measured at the tip of the LAA in the basal short-axis view. LAA emptying (LAAEV) and filling (LAAFV) velocities (m/s) were also recorded 1 cm below the orifice of the appendage. LAA ejection fraction was also measured. In addition, two-dimensional imaging was used to determine the presence of thrombus and/or spontaneous echo contrast (SEC). Patients with mitral stenosis in SR had significantly decreased LAAEV, LAAFV, SaV, and LAA ejection fraction compared to controls (0.34 +/- 0.15 vs 0.72 +/- 0.17, 0.37 +/- 0.13 vs 0.63 +/- 0.19, 0.050 +/- 0.015 vs 0.071 +/- 0.093, and 39 +/- 14% vs 69 +/- 13%, respectively, P < 0.001, P < 0.001, P < 0.001, and P < 0.001). Among the patients with mitral stenosis in SR, 10 patients had SEC and one had LAA thrombus. Compared with patients without SEC, patients with SEC had decreased LAAEV, LAAFV, SaV, and LAA ejection fraction (0.24 +/- 0.05 vs 0.37 +/- 0.16, 0.29 +/- 0.05 vs 0.39 +/- 0.14, 0.039 +/- 0.087 vs 0.055 +/- 0.015, and 28 +/- 14% vs 43 +/- 12%, respectively, P = 0.01, P = 0.02, P = 0.01, and P = 0.006). In conclusion, these results suggest that the LAA dysfunction may occur in patients with mitral stenosis in SR and CDTI can successfully be used for the quantification of contraction at the tip of the LAA.

D-dimer determination as a screening tool to exclude atrial thrombi in atrial fibrillation

Conversion of atrial fi brillation (AF) to sinus rhythm carries a defi nite risk of systemic embolism. This risk can be reduced to an acceptable level by prior anticoagulation for 3 weeks or, alternatively, by exclusion of atrial thrombi with transesophageal echocardiography (TEE) before cardioversion. 1 Although earlier cardioversion according to TEE-guided strategy has potential advantages, 2,3 TEE requires special equipment and advanced skills, which may limit its availability. D-dimer, an indirect marker of fi brin formation, has been demonstrated to be a sensitive marker of activation of coagulation in various clinical conditions. 4 –7 In AF, elevated D-dimer levels have been reported to be associated with the duration of AF, 8 left atrial appendage dysfunction, 9 and the presence of atrial thrombus. 10,11 The potential role of D-dimer in refi ning embolic risk prediction in AF remains to be determined. The aims of our study were to analyze the relation of serum D-dimer to embolic risk determined on clinical grounds in patients with AF and to assess the test’s diagnostic utility to predict the presence or absence of atrial thrombi.  In a prospective design, we measured the plasma D-dimer concentration of consecutive patients admitted to our echocardiography laboratory for TEE before cardioversion. The local ethics committee approved the protocol. The examinations were performed after obtaining written informed consent. Patients with AF of 48 hours duration or atrial fl utter with documented history of AF were eligible. The exclusion criteria included any thromboembolic events within the previous 2 months and anticoagulant therapy for 7 days. Subjects underwent transthoracic and TEE. Echocardiographic studies were performed with an ATL instrument (HDI 3500 CV, Philips Ultrasound, Bothell, Washington) using a 1.67- to 3.2-MHz, phased-array head (P4 to P2) for transthoracic examination, and a 4- to 7-MHz omniplane probe (MPT7 to MPT4) for TEE. An intravenous line was placed and blood samples were obtained without tourniquet immediately before TEE. D-dimer measurements were obtained with the use of a quantitative sandwich immunochromatographic technique (Cardiac D-dimer; Roche Diagnostics, Mannheim, Germany). The investigators and attending physicians were blinded to the D-dimer test results. The fi nal interpretations of the TEEs were the result of the consensus of the same 2 experienced investigators based on real-time observation or off-line analysis of the studies. For D-dimer results below the measurement range, 0.1 g/ml was entered. Values are presented as mean SEM. To obtain normal distribution, D-dimer values were logarithmically transformed, and unpaired 2-tailed t tests were used to compare means. The independent predictive role of embolic predictors for log D-dimer was evaluated by multiple regression analysis. Sensitivity,

Fibrillatory wave amplitude as a marker of left atrial and left atrial appendage function, and a predictor of thromboembolic risk in patients with rheumatic mitral stenosis

Background: Patients with mitral stenosis, especially those with atrial fibrillation, are at increased risk for thromboembolic complications. Size of the left atrium, left atrial appendage dysfunction and severity of mitral stenosis are known risk factors for thromboembolism in patients with mitral stenosis. It has been postulated that F-wave amplitude on surface ECG is correlated with left atrial size, left atrial appendage function, and risk of thromboembolism in patients with nonrheumatic atrial fibrillation. The aims of this study were as follows: (1) to examine the relationship between surface ECG F-wave amplitude and left atrial appendage function, and (2) to assess the clinical significance of F-wave amplitude as it relates to risk of thromboembolism in a group of patients with rheumatic mitral stenosis. Material and Methods: One hundred patients with rheumatic mitral stenosis and permanent atrial fibrillation but without moderate to severe mitral insufficiency were investigated by transthoracic and transesophageal echocardiography. Two groups were formed according to the presence of a coarse (Group 1; n=60; F-wave in lead V 1≥1 mm) or fine (Group 2; n=40; F-wave in lead V 1<1 mm) F-wave on surface ECG. Results: Comparison showed that Group 1 had significantly smaller mitral valve area (1.44±0.6 versus 1.7±0.74 cm 2, respectively; P<0.05), lower peak left atrial appendage flow velocity (18.8±2.1 versus 25.6±1.9 cm/s, respectively; P<0.005), higher-grade spontaneous echo contrast (2.05±1.44 versus 0.98±1.14, respectively; P<0.0001), and higher prevalence of thromboembolism (35% versus 12.5%, respectively; P<0.012). Multiple logistic regression analysis revealed that mitral valve area, left atrial appendage peak velocity, and coarse F-wave were independent clinical risk factors for thromboembolism in this patient group. Conclusion: The data suggest that presence of a coarse F-wave on surface ECG is associated with left atrial appendage dysfunction, and indicates higher thromboembolic risk in patients with predominant rheumatic mitral stenosis.

P1664 Determinants of early normalization of post-cardioversion mechanical dysfunction of left atrial appendage in patients with non-valvular atrial fibrillation

P1664 Determinants of early normalization of post-cardioversion mechanical dysfunction of left atrial appendage in patients with non-valvular atrial fibrillation

Left atrial appendage function in patients with mitral stenosis in sinus rhythm.

Left atrial appendage thrombi are believed to be the source of embolism in patients with rheumatic mitral stenosis in atrial fibrillation. There are a few studies which search the effects of left atrial appendage dysfunction in patients with mitral stenosis in sinus rhythm. Left atrial appendage function and flow patterns in 41 patients with rheumatic mitral stenosis in sinus rhythm and 11 healthy subjects were studied by transoesophageal echocardiography. Left atrial appendage flow profiles were recorded within the proximal third of the appendage. The left atrial appendage ejection fraction was expressed as (maximal area of appendage minimal area of appendage)/maximal area of appendage. In addition, two-dimensional imaging was used to determine the presence of spontaneous echocardiographic contrast and thrombus formation. Patients with mitral stenosis in sinus rhythm had significantly decreased left atrial appendage emptying and filling velocities compared to controls (0.40+/-0.15m/s vs 0.82+/-0.19 m/s and 0.42+/-0.21 m/s vs 0.68+/-0.28, respectively, P<0.001 and P<0.05). Compared with the control subjects, patients with mitral stenosis had significantly greater maximal area of the appendage and had reduced left atrial appendage ejection fraction (5.3+/-2.2 cm(2) vs 2.4+/-0.5 cm(2) and 50+/-16% vs 70+/-7%, respectively, P<0.001 and P<0.05). Of the patients with mitral stenosis in sinus rhythm, seven patients had spontaneous echocardiographic contrast and one of these had left atrial appendage thrombus. Compared with patients without spontaneous echocardiographic contrast, patients with spontaneous echocardiographic contrast had decreased left atrial appendage ejection fraction (33+/-21% vs 54+/-13%,P <0.01). One of the patients with mitral stenosis had central retinal artery occlusion, but thrombus was not observed in left atrial appendage. The study found that left atrial appendage dysfunction may occur in patients with mitral stenosis in sinus rhythm.

Multiplane Transesophageal Echocardiographic Assessment of Left Atrial Appendage

Background and Objectives:Transesophageal echocardiography (TEE) allows a detailed evaluation of the structure and function of the left atrial appendage (LAA) by two-dimensional imaging and Doppler interrogation of appendage flow. LAA dysfunction has been associated with spontaneous echo contrast (SEC), thrombus formation and thromboembolism. The purpose of this study was to define normal heart reference values of LAA maximal forward velocity (LAAV), and to correlate LAAV with cardiac rhythm, mitral valve disease severity, SEC grade and left atrial thrombi development. Subjects and Methods:LAA volume measurement and pulse Doppler evaluation of LA appendage flow during TEE were undertaken in 95 subjects;32 patients with normal heart and 63 patients with various cardiac diseases. Results:Mean LAAV was 87.1±26.7 cm/s, mean LAA maximal backward velocity 66.0±15.0 cm/s and mean LAA volume 2.2±1.2 mL in those patients with normal heart (n=32). There was a negative correlation between LAAV and SEC grade, mitral stenosis severity, LA size and LAA volume. Among those patients with atrial fibrillation, LAAV was lower in the subgroup with LA thrombi than in the subgroup without thrombi (14.9±8.1 cm/s (n=16), vs. 29.7±21.2 cm/s (n=33), p<0.01). Conclusion:Reduced LAAV, SEC and mitral stenosis are all associated with LAA thrombus formation in patients with atrial fibrillation. (Korean Circulation J 2002;32(2):137-145)