Atrial Appendage Spontaneous Echo Contrast Research Articles

The value of left atrial longitudinal strain in evaluating left atrial appendage spontaneous echo contrast in non-valvular atrial fibrillation.

Spontaneous echo contrast (SEC) observed in transesophageal echocardiography (TEE) is a reliable predictor of the risk of future ischemic stroke in patients with non-valvular atrial fibrillation (NVAF). Left atrial strain globally reflects atrial function, remodeling and distensibility. The left atrial appendage (LAA) is a myogenic remnant of the left atrium, which can actively relax and contract. The left atrial appendage (LAA) is an important part of releasing the pressure of the left atrium. The key role of the left atrium is to regulate the left ventricular filling pressure, act as a reservoir for pulmonary venous return during ventricular contraction, and act as a conduit, transferring blood to the Left ventricle during early ventricular diastole. The purpose of this study was to explore the relationship between left atrial function and left atrial appendage spontaneous echo contrast (LAASEC). A retrospective study of 338 patients with non-valvular AF was conducted. Two-dimensional speckle-tracking echocardiography provided the following metrics of LA strain: LA strain during the reservoir phase (LASr), LA strain during the conduit phase (LAScd). LA or LAA has the dense SEC of more than grade 3, which is defined as mud like change or pre thrombosis. Patients with level 3 SEC (n = 81) has lower LASr than those with lower grades of SEC (n = 257) (7.20 ± 3.70 vs. 17.48 ± 8.67, P < 0.001). Multivariate logistic regression model showed that the type of atrial fibrillation (persistent∼), increased heart rate, decreased LASr were independently associated with the dense LAASEC (OR (CI 95%), 5.558 (1.618-19.09), 1.016 (1.006-1.026) 0.002, 1.224 (1.085-1.381), both P < 0.01). Venn Diagram showed that lower CHADVASC2 score groups had dense SEC cases. Receiver operating characteristic (ROC) curve was used for analyzing results and selecting cut off values. The cut off point for LASr < 8.85% and CHADVASC2 score was >2 scores with sensitivity and specificity were 79% and 85%. Lower LASr is independently associated with the dense LAASEC in NVAF and has incremental values superior to clinical scores. The decrease of LASr may be a potential non-invasive parameter for evaluating the higher risk of LAA thrombosis.

Clinical study on influencing factors for left atrial appendage spontaneous echo contrast or thrombosis in patients with non-valvular atrial fibrillation

Objective To investigate the influencing factors for left atrial appendage(LAA) spontaneous echo contrast (SEC) or thrombosis in patients with non-valvular atrial fibrillation(NVAF) and normal left ventricular ejection fraction(LVEF). Methods This study prospectively enrolled 255 patients with NVAF [paroxysmal atrial fibrillation(PaAF) 196 cases and persistent atrial fibrillation(PeAF) 59 cases]. Patients were divided into two groups according to the findings on transesophageal echocardiography(TEE): positive group with the presence of the LAA SEC or thrombosis (group Ⅰ) and negative group(group Ⅱ) without this two presences. The clinical and echocardiographic data were compared between the two groups. The multivariate logistic regression analysis was used to explore the independent risk factors for development of LAA SEC or thrombosis. Receiver operating characteristic (ROC) curve was performed to determine the predictive value of the factors. Results A total of 255 patients were enrolled. There were 26 cases(10.2%) in group Ⅰ, and 229 cases (89.8%) in group Ⅱ. The age, NT-proBNP, occurrence rate of PeAF, left atrial volume index(LAVI), and LAA orifice long diameter and depth were higher in group Ⅰ than those in group Ⅱ(all P<0.01). The left atrial appendage emptying velocity(LAAV), global left atrial longitudinal strain(GLALS) and LVEF were lower in group Ⅰ compared with those in group Ⅱ (all P<0.01). Multivariate logistic regression analysis and ROC curve showed that GLALS<12.2% and LAAV<31.2 cm/s were independent risk factors of LAA SEC or thrombosis in patients with NVAF and perserved LVEF. Conclusions The impairment of left atrial and LAA function are potential risk factors for cardiogenic embolism. GLALS and LAAV can be used as useful referenced parameters for prediction of stroke in patients with NVAF. Key words: Echocardiography, transesophageal; Atrial fibrillation; Atrial function, left; Left atrial appendage; Spontaneous echo contrast; Strain

Comparison of Transesophageal Echocardiography Versus Computed Tomography for Detection of Left Atrial Appendage Filling Defect (Thrombus)

Patients with atrial fibrillation, who are referred for radiofrequency pulmonary vein antral isolation, frequently undergo transesophageal echocardiography (TEE) to detect and/or exclude left atrial or left atrial appendage (LAA) thrombus and cardiac computed tomographic angiography (CCTA) to define and/or evaluate left atrial and pulmonary venous anatomy. Previous studies have reported CCTA to have high sensitivity and negative predictive value (NPV) for detecting thrombus in the LAA. Previous studies determining an optimal LAA/ascending aorta (AA) Hounsfield unit (HU) density ratio for detection of LAA thrombus have been small, with limited numbers of thrombi. We thus sought to determine both the optimal cutoff for LAA HU density and LAA/AA HU density ratio in detecting LAA thrombus compared with TEE in a multicenter population. We included 84 patients who had undergone CCTA and TEE. LAA was evaluated by 64-row CCTA qualitatively (visual filling defect) and quantitatively (measurement of LAA HU density and LAA/AA HU density ratio), using a 1-cm area of interest in the same axial plane. Results were compared with TEE visualization of thrombus or spontaneous echo contrast. Qualitative identification of thrombus in LAA by CCTA compared with TEE detection of thrombus had a sensitivity of 100%, a specificity of 77.9%, a positive predictive value (PPV) of 51.6%, an NPV of 100%, and a total accuracy of 82.1%. The optimal LAA HU density cutoff for thrombus detection was 119 with a sensitivity of 88%, a specificity of 86%, PPV 56%, and an area under the curve of 0.923 (p = 0.0004). The optimal LAA/aorta HU ratio was 0.242 with a sensitivity of 87%, a specificity of 88%, a PPV of 64%, and an area under the curve of 0.921 (p = 0.0011). There is no significant difference (p = 0.72) between both areas under the curve, and both measurements improved the specificity and PPV compared with qualitative measures. Multidetector computed tomography is an imaging technique that can exclude LAA thrombus with very high NPV. Quantitative measurement of LAA HU density (cutoff 119) or LAA/aorta HU density ratio (cutoff 0.242) improves accuracy of positively detecting LAA thrombus. This technique is especially useful when delayed scanning is not performed and LAA is found incidentally after the patient scanning is complete.

Clinical and Echocardiographic Risk Factors for Embolization in the Presence of Left Atrial Thrombus

The aim of our study was to evaluate the factors leading to embolization in patients with left atrial thrombi (LAT). With this purpose, we retrospectively analyzed clinical, transthoracic, transesophageal echocardiographic data of patients with LAT in the transesophageal echocardiographic evaluation. One hundred ninety-two patients with LAT not on anticoagulant therapy were divided into two groups according to the presence of prior ischemic stroke. The group with ischemic stroke included more patients with sinus rhythm and less patients with mitral stenosis. They had smaller left atrial diameter, more left atrial appendage spontaneous echo-contrast, higher appendage ejection fraction, and emptying velocity. Once the thrombus has been formed, cerebral embolization seems to be higher in patients with relatively preserved appendage ejection fraction and emptying velocity. Presence of atrial appendage spontaneous echo-contrast also favor embolization. Factors leading to embolization seem to differ in some respects from the causes of thrombus formation.

Contrast-enhanced tissue Doppler imaging of the left atrial appendage is a new quantitative measure of spontaneous echocardiographic contrast in atrial fibrillation

Although left atrial appendage spontaneous echo contrast (LAASEC) is a marker of increased thromboembolic risk in atrial fibrillation, it has previously only been evaluated qualitatively. We sought to determine if an intravenous contrast echocardiographic agent combined with tissue Doppler imaging (TDI) of the LAA could accurately quantify LAA-SEC in patients with atrial fibrillation. We prospectively identified 55 patients with persistent atrial arrhythmias (mean age 63+/-13 years) undergoing a transesophageal echocardiography (TEE), with LAA-SEC prior to direct current cardioversion. In addition to off-line calculation of backscatter index and shear rate, quantification of the velocity in a color TDI region of interest was performed in the LAA cavity following a 0.5-mL intravenous bolus of Optison. LAA-SEC was qualitatively graded by a blindedreader as mild (n = 29) or severe (n = 26), and was compared off-line to TEE-derived quantitative variables. Compared to patients with mild LAA-SEC, those with severe LAA-SEC had significantly decreased LAA emptying velocity, LAA TDI mean velocities and shear rate. Over the whole group, the mean maximal velocity of the LAA using TDI correlated with LAA emptying velocity (r = 0.59; P < 0.0001), shear rate (r = 0.55; P < 0.0001) and LAA area (r = 0.34; P = 0.014). Severe LAA-SEC was found with 72% sensitivity and 82% specificity if TDI mean velocity was <6.13 cm/s. On logistic regression analysis, LAA-TDI was the only predictor of qualitative LAA-SEC grade. Contrast-enhanced TDI is an original new tool that provides a quantification of the mean velocity of LAA-SEC that might improve our decision making in patients with atrial fibrillation.

Echocardiographic Predictors of Left Atrial Appendage Spontaneous Echocontrast in Patients with Stroke and Atrial Fibrillation

The presence of spontaneous echocontrast (SEC) in the left atrium (LA) or LA appendage (LAA) has been associated with a higher risk of thromboembolism and cerebrovascular accidents. The purpose of this study was to define the new transesophageal echocardiographic predictors of SEC for patients with stroke and atrial fibrillation. We studied 47 patients with stroke and atrial fibrillation who were undergoing transesophageal echocardiography for the evaluation of source of cardiac emboli. Patients were divided into two groups based on the absence (group 1) or presence (group 2) of SEC in the LAA. Compared with group 1, group 2 had larger LA, larger LAA minimum and maximum areas, and decreased LAA flow velocity, LAA wall velocity, LAA tissue intensity, and intensity ratio. In the stepwise discriminate analysis tissue intensity of LAA, minimum LAA area, LAA flow velocity, and LAA wall velocity were found as independent predictors of LAA SEC. LAA wall velocity had the greatest area under the receiver operating characteristic curve, indicating that the most powerful parameter for SEC is LAA wall velocity. Decreased LAA flow velocity and LA wall velocity, increased LAA size, and less negative LAA tissue intensity are associated with SEC in patients with nonvalvular atrial fibrillation. Strain and strain measurements of LAA give no more benefit.

Left atrial appendage spontaneous echo contrast in patients with atrial arrhythmias using integrated backscatter and transesophageal echocardiography

In contrast to nonspecific postrace elevations in myoglobin and CK-MB as early-stage markers for AMI due to exertional rhabdomyolysis of trained skeletal muscle, late-stage markers including cTnI and cTnT remained negative with rapid quantitative methods within 24 hours after competition. A 6.5-fold increase in cTnI by high-sensitivity methods as predictive of poor outcome in patients with acute coronary syndromes occurred in these middle-aged male runners without evidence for microinfarction by SPECT sestamibi myocardial scintigraphy, for left ventricular dysfunction by BNP, or for apparent risk of cardiac events over 4 years.

Clinical Significance of Fibrillatory Wave Amplitude: A Clue to Left Atrial Appendage Function in Nonrheumatic Atrial Fibrillation

Seventy-eight patients with chronic nonrheumatic atrial fibrillation were studied by transesophageal echocardiography with regard to the left atrial appendage function and its relation to the coarseness of atrial fibrillation on electrocardiogram. These 78 patients (52 men and 26 women; mean age, 66 +/- 10 years; range, 40 to 94 years) were classified into two groups according to the presence of coarse (group 1, n = 46; those with the greatest amplitude of fibrillatory wave in lead V1 > or = 1 mm) or fine (group 2, n = 32; those without the coarse fibrillatory wave in lead V1) atrial fibrillation on a standard 12-lead electrocardiogram within 1 month of echocardiographic studies. There were no significant differences in age, sex, mean duration of atrial fibrillation, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, and left atrial dimension between the two groups. In group 1, however, the left atrial appendage ejection fraction (24.4 +/- 14.2% vs 32.6 +/- 14.8%; p < 0.05) and the peak emptying velocity (21.7 +/- 12.6 cm/s vs 30.4 +/- 14.3 cm/s; p < 0.01) were lower than those in group 2. There were higher incidences of left atrial appendage spontaneous echo contrast (26/46 vs 7/32; p < 0.005) and thrombus (8/46 vs 0/32; p < 0.05) in group 1 patients. The coarse atrial fibrillation revealed a sensitivity of 80.0%, a specificity of 58.1%, a positive predictive value of 60.9%, and a negative predictive value of 78.1% for the presence of left atrial appendage spontaneous echo contrast and/or thrombus formation. In conclusion, in patients with coarse nonrheumatic atrial fibrillation, the left atrial appendage function is usually poor and the incidence of spontaneous echo contrast and thrombus formation appears to be higher in these patients.

Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: Characterization by simultaneous transesophageal echocardiography

Objectives. This study assessed the function of the left atrial appendage in the pericardioversion period to gain insights into mechanisms involved in thromboembolism after cardioversion of atrial fibrillation.Background. Systemic embolization associated with electrical cardioversion of atrial fibrillation is thought to originate from the left atrium or left atrial appendage, or both. However, the mechanism involved is poorly understood.Methods. We studied left atrial appendage function with transesophageal echocardiography in 20 patients with atrial fibrillation before and after successful electrical cardioversion. We measured left atrial appendage emptying and filling velocities by pulsed wave Doppler echocardiography, characterized Doppler emptying patterns, measured atrial appendage areas and assessed the presence or absence of spontaneous echo contrast or thrombus.Results. Organized left atrial appendage function returned in 16 (80%) of 20 patients immediately after cardioversion. Atrial appendage emptying velocities before cardioversion were greater in patients without (0.39 ± 0.02 m/s) than in those with (0.25 ± 0.12 m/s) spontaneous echo contrast (p = 0.045). Furthermore, emptying velocities before cardioversion were significantly greater than late diastolic emptying velocities after cardioversion (0.31 ± 0.15 vs. 0.14 ± 0.12 m/s, p = 0.0001), as well as in both the with (0.25 ± 0.12 vs. 0.13 ± 0.13 m/s, p = 0.001) and the group without (0.39 ± 0.02 vs. 0.15 ± 0.12 m/s, p = 0.01) spontaneous echo contrast. In addition, left atrial and atrial appendage spontaneous echo contrast developed in 4 of 20 patients and increased in intensity in 3 of 20 patients in the immediate postcardioversion period.Conclusions. Organized left atrial appendage function returns in most patients immediately after cardioversion of atrial fibrillation. However, its function is impaired compared with that before cardioversion. Furthermore, spontaneous echo contrast increased in 7 (31%) of 20 patients after cardioversion. These observations suggest that stunned left atrial function after cardioversion may predispose the chamber to thrombus formation, which may play a role in the mechanism involved in the occurrence of embolization after cardioversion.