Effects of left ventricular systolic dysfunction on left atrial appendage and left atrial functions in patients with chronic nonvalvular atrial fibrillation

OBJECTIVE: It has been claimed that left ventricular (LV) systolic dysfunction impairs left atrial (LA) and left atrial appendage (LAA) functions. In this study, we compared the LA and LAA function parameters in patients with chronic nonvalvular atrial fibrillation (AF) with and without LV systolic dysfunction. METHODS AND RESULTS: The study population consisted of 28 patients with chronic nonvalvularAF. Group I consisted of 12 patients with LV systolic dysfunction (mean age: 61 +/- 14 years; LV ejection fraction: 44 +/- 6%), group II of 16 patients with normal LV systolic function (mean age: 52 +/- 15 years; LV ejection fraction: 65 +/- 3%). LV ejection fraction (EF) was measured by echocardiography utilizing bi-plane area length method.The following LA and LAA transoesophageal echocardiography parameters were obtained: I) LA diameter, 2) LAA ejection velocity, 3) LAA filling velocity, 4) LAA ejection fraction, 5) pulmonary venous (PV) systolic velocity, 6) PV diastolic velocity, 7) PV systolic velocity/diastolic velocity ratio.The left atrium diameter was significantly larger in group I than in group 11 (4.7 +/- 0.7 cm vs. 3.8 +/- 0.6 cm, p < 0.05).The LAA ejection velocity and LAA ejection fraction were significantly lower in group I than in group 11 (22.6 +/- 15.5 cm/s vs 37.5 +/- 11.3 cm/s and 26.9 +/- 20.8% vs. 41.3 +/- 10.9%, p < 0.05 for both comparisons).The PV systolic velocity and PV systolic velocity/diastolic velocity ratio were significantly smaller in group I than in group II (26.2 +/- 14.8 cm/s vs. 51.5 +/- 22 cm/s and 0.7 +/- 0.6 vs. 1.2 +/- 0.5, p < 0.05 for both comparisons).Although decreased LAA filling and PV diastolic velocities were determined in group I, no significant difference existed between groups I and II.Thrombus and/or spontaneous echo contrast (SEC) in the LA and/or LAA were more frequent in group I (75% vs. 18%, p < 0.05). CONCLUSION: These results indicate that LV systolic dysfunction impairs various LA and LA function parameters and is associated with an increased frequency of SEC and/or LA thrombus in patients with chronic nonvalvularAF.     

Left atrial appendage function and pulmonary venous flow in patients with nonrheumatic atrial fibrillation and their relation to spontaneous echo contrast

This study analyzed the relation between frequency of left atrial appendage (LAA) contractions, pulmonary venous flow (PVF) parameters, and spontaneous echo contrast (SEC). Thirty-six patients (22 male, 14 female, mean age 61 plus minus 11 years) with nonrheumatic atrial fibrillation undergoing transesophageal echocardiography were studied. Doppler flow was obtained from both the LAA and the left upper pulmonary vein. Fourier analysis was applied to the LAA signal that exhibited the frequency of LAA contractions. LAA emptying velocity and PVF parameters were determined. There was no relation between velocity and frequency of LAA flow (r = 0.256, P = ns). Among LAA and PVF parameters, patients with left atrial SEC (n = 17) had a lower LAA velocity (16.8 +/- 10.8 cm/sec vs 35.6 +/- 13.2 cm/sec, P < 0.001), a larger LAA area (4.8 +/- 2.2 cm(2) vs 3.0 +/- 1.3 cm(2), P = 0.008), and a reduced systolic velocity time integral of PVF (3.4 +/- 2.2 cm vs 5.4 +/- 2.2 cm, P = 0.017) when compared with patients without SEC. Frequency of LAA contractions was similar between both groups (6.8 +/- 0.4 Hz vs 6.8 +/- 1.0 Hz, P = ns). In conclusion, the rate of LAA contraction does not correlate with LAA flow velocity and SEC. A low left atrial flow expressed by low LAA flow velocity and a reduction in systolic PVF is a major hemodynamic determinant for the occurrence of SEC.     

Relationship between left atrial appendage function and left atrial thrombus in patients with nonvalvular chronic atrial fibrillation and atrial flutter.

The relationship between the left atrial appendage (LAA) function, as assessed by transesophageal echocardiography, and the incidence of left atrial thrombus was evaluated in 62 patients with nonvalvular chronic atrial fibrillation (AF; n=50) and atrial flutter (AFL; n=12). It was hypothesized that in both AF and AFL not only the LAA flow velocity (LAAFV), but also the frequency of the LAA movement (the LAA flow time, LAAFT) is a major contributing factor to thrombus formation. LAAFT was defined as the average duration of LAA flow with emptying and filling waves. The patients with AF were divided into 2 groups: lone AF (n=14) and non-lone AF (n=36). LAA thrombus was found in 6 patients with none-lone AF. LAAFV was lower and LAAFT was shorter in patients with thrombus as compared with patients without thrombus (12.0+/-2.2 cm/s vs 24.1+/-10.6 cm/s, 68.7+/-1.5 ms vs 72.9+/-3.3 ms, p<0.01, respectively). Patients with AFL had higher LAAFV and longer LAAFT than those with chronic AF. The present data suggest that, in addition to LAAFV, LAAFT characterized LAA function and might serve as a predictor of thrombus formation in chronic AF. With respect to LAA function, patients with lone AF or AFL are at low risk for thrombus formation.     

Effects of heart rate on flow velocity of the left atrial appendage in patients with nonvalvular atrial fibrillation

Background and hypothesis: Flow velocity of the left atrial appendage (LAA) is thought to be important in thrombus formation in association with blood stasis and the development of spontaneous echo contrast. The effects of heart rate on peak flow velocity of the LAA have not been studied in patients with nonvalvular atrial fibrillaton. Methods: Using transesophageal Doppler echocardiography, peak flow velocity of the LAA was measured at the junction between the left atrium and the LAA during left ventricular (LV) systole and diastole in 21 patients with nonvalvular atrial fibrillation. In six cases, the average peak flow velocity of the LAA for 10 consecutive beats with moderately long R-R intervals (LI beats) was compared with those for 3-5 consecutive beats with extremely short R-R intervals (SI bets). Results: Average peak flow velocity of the LAA during LV diastole was significantly higher than that during LV systole (26.5 ± 15.7 vs. 19.3 ± 10.4 cm/s, p<0.01). In SI beats, average peak flow velocity of the LAA was significantly lower than that in LI beats (17.1 ± 12.1 vs. 21.2 ± 12.9 cm/s, p<0.01). Conclusion: An increased heart rate reduced the peak flow velocity of the LAA in patients with nonvalvular atrial fibrillation, which would promote blood stasis in the LAA.     

Direct evidence that sustained dysfunction of left atrial appendage contributes to the occurrence of cardiogenic brain embolism in patients with paroxysmal atrial fibrillation

OBJECTIVE: The goal of this study was to investigate transesophageal echocardiographic (TEE) findings after the termination of atrial fibrillation to clarify the direct evidence for occurrence of acute cardiogenic brain embolism (CBE) in patients with paroxysmal atrial fibrillation (PAF). PATIENTS AND METHODS: Among 98 consecutive patients with CBE, we investigated TEE in 16 patients with PAF (Group CBE, 72 +/- 10 years) within 7 days of the onset and 2 weeks after the first study, in comparison with 15 age-matched PAF patients without CBE (Group N). The duration from reversal to normal sinus rhythm to first TEE was 6 +/- 1 days in both groups. RESULTS: There were no significant differences in left atrial dimension and emptying flow velocity of the left atrial appendage (LAA-eV) between groups. Group CBE had significantly larger LAA area (4.3 +/- 1.3 cm2 vs. 3.1 +/- 1.0 cm2, p < 0.05), smaller LAA fractional area change (LAA-FAC) (43 +/- 25% vs. 80 +/- 22%, p < 0.001), and a higher incidence of left atrial spontaneous echo contrast (LAA-SEC) (25% vs. 7%, p < 0.05) than group N, and those abnormalities in group CBE were significantly improved at the second TEE (LAA area: to 3.2 +/- 0.9 cm2, p < 0.05; LAA-FAC: to 84 +/- 26%, p < 0.001; LAA-SEC: to 0%, p < 0.05), respectively. CONCLUSION: LAA-FAC is a more sensitive marker for LAA dysfunction than the widely used index, LAA-eV, and a sustained deterioration of LAA-FAC may be direct evidence for thrombus formation and occurrence of acute CBE in patients with PAF.     

Clinical value of left atrial appendage flow for prediction of long-term sinus rhythm maintenance in patients with nonvalvular atrial fibrillation

OBJECTIVES: This study evaluated the role of various clinical and echocardiographic parameters, including the left atrial appendage (LAA) anterograde flow velocity, for prediction of the long-term preservation of sinus rhythm (SR) in patients with successful cardioversion (CV) of nonvalvular atrial fibrillation (AF). BACKGROUND: Echocardiographic parameters for assessing long-term SR maintenance after successful CV of nonvalvular AF are not accurately defined. METHODS: Clinical, transthoracic echocardiographic and transesophageal echocardiographic (TEE) data--measured in AF lasting >48 h--of 186 consecutive patients (116 men, mean age: 65 +/- 9 years) with successful CV (electrical or pharmacologic) were analyzed for assessment of one-year maintenance of SR. RESULTS: At one-year follow-up, 91 of 186 (49%) patients who underwent successful CV continued to have SR. Mean LAA peak emptying flow velocity was higher in patients remaining in SR for one year than in those with AF relapse (41.7 +/- 20.2 cm/s vs. 27.7 +/- 17.0 cm/s; p < 0.001). On multivariate logistic regression analysis, only the mean LAA peak emptying velocity >40 cm/s (p = 0.0001; chi(2): 23.9, odds ratio [OR] = 5.2, confidence interval [CI] 95% = 2.7 to 10.1) and the use of preventive antiarrhythmic drug treatment (p = 0.0398; chi(2): 4.2; OR = 2.0, CI 95% = 1.0 to 3.8) predicted the continuous preservation of SR during one year, outperforming other univariate predictors such as absence of left atrial spontaneous echocardiographic contrast during TEE, the left atrial parasternal diameter <44 mm, left ventricular ejection fraction >46% and AF duration <1 week before CV. The negative and positive predictive values of the mean LAA peak emptying velocity >40 cm/s for assessing preservation of SR were 66% (CI 95% = 56.9 to 74.2) and 73% (CI 95% = 62.4 to 83.3), respectively. CONCLUSIONS: In TEE-guided management of nonvalvular AF, high LAA flow velocity identifies patients with greater likelihood to remain in SR for one year after successful CV. Low LAA velocity is of limited value in identifying patients who will relapse into AF.     

Assessment of left atrial appendage function by transesophageal echocardiography. Implications for the development of thrombus

BACKGROUND. The predilection of the left atrial appendage (LAA) for thrombus formation has long been known. METHODS AND RESULTS. We prospectively studied the two-dimensional echocardiographic and Doppler patterns of LAA function in 82 patients by transesophageal echocardiography. In the 63 patients in sinus rhythm, LAA area was measured during LAA diastole at the onset of the electrocardiographic (ECG) P wave (LAAmax) and after LAA systole at the ECG R wave (LAAmin) and LAA ejection fraction was calculated as (LAAmax-LAAmin)/LAAmax; peak Doppler velocity was recorded from the LAA outlet. The 58 patients in sinus rhythm without LAA thrombus were grouped according to left atrial size on transthoracic echocardiography; 39 patients had a left atrial size of less than 40 mm (group 1) and 19 had a left atrial size of 40 mm or greater (group 2). Five patients in sinus rhythm had LAA thrombus. In the 19 patients with atrial fibrillation or flutter LAAmax was measured independent of the ECG; three of these patients had LAA spontaneous contrast, four had thrombus, and one had both. Patients in sinus rhythm without LAA thrombus demonstrated a characteristic pattern of a contractile LAA apex and a noncontractile base with color flow and pulsed Doppler evidence of LAA emptying that coincided with the P wave. Patients in sinus rhythm with LAA thrombus had a mean +/- SD LAAmax (8.0 +/- 1.5 cm2) larger than that in group 1 (5.0 +/- 1.9 cm2) (p less than 0.01) but not group 2 (6.7 +/- 3.1 cm2), LAAmin (6.5 +/- 1.0 cm2) larger than that in both group 1 (2.3 +/- 1.5 cm2) and group 2 (4.2 +/- 2.7 cm2) (p less than 0.01), and LAA ejection fraction (17 +/- 11%) and LAA velocity (0.24 +/- 0.10 m/sec) less than those in both group 1 (55 +/- 21% and 0.48 +/- 0.24 m/sec, respectively) and group 2 (45 +/- 27% and 0.46 +/- 0.24 m/sec, respectively) (p less than 0.01). Patients with atrial fibrillation or flutter with LAA spontaneous contrast and/or thrombus had LAAmax (10.4 +/- 6.6 cm2) greater than that in patients with atrial fibrillation or flutter without LAA contrast and/or thrombus (6.8 +/- 3.0 cm2) (p less than 0.05). The LAA appeared as a static pouch in seven of eight of the former compared with in two of 11 of the latter. When attempted, Doppler demonstrated a recognizable fibrillatory LAA outflow velocity pattern in none of three in the former versus four of seven in the latter group. CONCLUSIONS. We conclude that the LAA has a characteristic pattern of emptying in sinus rhythm. LAA thrombus formation in sinus rhythm and atrial fibrillation is associated with both poor LAA contraction and LAA dilation.     

Color Doppler tissue imaging to evaluate left atrial appendage function in mitral stenosis

Two-dimensional color Doppler tissue imaging (CDTI) has so far been used, in general, to evaluate ventricular function. This study examined if the left atrial appendage tissue velocity could reproducibly be measured with CDTI and if they have any predictive value for left atrial appendage (LAA) function and former thromboembolism. Thirty-six patients (24 women, 12 men; mean age 45 +/- 12 years; 18 AF; 11 former thromboembolic stroke) with mitral stenosis undergoing transesophageal echocardiography were examined with CDTI. Peak systolic tissue velocity (m/sec, peak systolic velocity [PSV]) was measured at the tip of the LAA in the basal short-axis view. LAA flow emptying (LAAEV) and filling (LAAFV) velocities (m/sec) were also recorded 1 cm immediately below the orifice of the appendage. Interobserver and intraobserver variabilities were determined for the PSV. LAA ejection fraction was measured by Simpson's method. Mitral regurgitation, AF, transmitral mean gradient, left ventricular ejection fraction, mitral valve area, and left atrial diameter were used as a covariant for adjustment. The intraobserver and interobserver correlation coefficients for the PSV using CDTI was 0.64 and 0.60, respectively (bothP = 0.01). LAAEV(0.29 +/- 0.09 vs 0.19 +/- 0.04, P = 0.001)and LAA ejection fraction(44 +/- 12 vs 29 +/- 14, P = 0.004)were found to be significantly decreased in the patients with decreased PSV (<0.05 m/sec), even after adjustment. The decreased PSV was positively correlated with the low LAAEV (<0.25 m/sec) and history of thromboembolism (r = 0.59, r = 0.38, respectively), and remained a significant determinant of the low LAAEV (OR 50.03, CI 1.46-1738.11,P = 0.02), but not of history of thromboembolism (OR 4.29, CI 0.52-35.01,P = 0.08) after adjustment. In conclusion, these results suggest that CDTI provides a reproducible method for quantification of contraction at the tip of the LAA. Decreased PSV may be predictive of poor LAA function.     

The effect of transient balloon occlusion of the mitral valve on left atrial appendage blood flow velocity and spontaneous echo contrast

BACKGROUND: Spontaneous echo contrast (SEC) is a phenomenon that is commonly seen in areas of blood stasis. It is a slowly moving, cloud-like swirling pattern of "smoke" or increased echogenicity recorded on echocardiography. SEC is commonly seen in the left atrium of patients with mitral stenosis or atrial fibrillation. The presence of SEC has been shown to be a marker of increased thromboembolic risk. HYPOTHESIS: By using transesophageal echocardiography during percutaneous balloon mitral valvotomy (PBMV), the study investigated the relationship between SEC and varying left atrial appendage (LAA) blood flow velocity in the human heart. METHODS: Thirty-five patients with rheumatic mitral stenosis underwent percutaneous balloon mitral valvotomy with intraoperative transesophageal echocardiography monitoring. We alternatively measured LAA velocities and observed the left atrium for various grades of SEC (0 = none to 4 = severe) before and after each balloon inflation. RESULTS: Left atrial appendage maximal ejection velocity was reduced from 35 +/- 14 to 6 +/- 2 mm/s at peak balloon inflation and increased to 40 +/- 16 mm/s after balloon deflation. In comparison with the values before balloon inflation and after balloon deflation, LAA velocities were significantly lower (p < 0.001). New or increased SEC grade was observed during 54 of 61 (88%) inflations and unchanged in 7 (12%) inflations at peak balloon inflation. Spontaneous echo contrast became lower in grade after 55 balloon deflations (90%), completely disappeared after 18 deflations (30%), and remained unchanged after 6 deflations (10%). The mean time to achieve maximal SEC grade (2.5 +/- 1.2 s) coincided with the mean time to trough LAA velocities (2.3 +/- 1.1 s) after balloon inflation. Upon deflation, the mean time to lowest SEC grade (2.9 +/- 1.8 s) coincided with mean time to achieve maximal LAA velocities (2.7 +/- 1.6 s). CONCLUSION: During balloon inflation, the severity of SEC was enhanced with corresponding reduction in LAA flow velocity. Upon balloon deflation, SEC lightens or disappears with increase in LAA flow velocity.     

Left atrial appendage Doppler flow patterns: implications on thrombus formation.

The characteristics and clinical implications of left atrial appendage (LAA) flow have not been clearly analyzed. Thirty-nine consecutive patients underwent a transesophageal echocardiographic (TEE) color Doppler study to correlate the LAA pulsed Doppler flow pattern with echocardiographic variables and the cardiac rhythm of each patient. Three different LAA flow patterns were identified. Type I flow, characterized by a biphasic pattern (waves of filling and emptying), was found in 17 patients, all in sinus rhythm; it was not associated with LAA spontaneous contrast or thrombus. Mean peak velocities of the filling and emptying waves were, respectively: 28 +/- 12 cm/sec and 31 +/- 9 cm/sec. Type II sawtooth active flow (eight patients) (mean peak velocity: 49 +/- 12 cm/sec) was only detected in atrial fibrillation (AF) and dilated LAA (LAA area: 421 +/- 40 mm2) but without thrombus or significant LAA spontaneous echocardiographic contrast. Type III flow pattern was noted in 14 patients with AF and a very dilated LAA (LAA area: 619 +/- 96 mm2). This flow pattern was characterized by the absence of identifiable flow waves and was associated with the presence of LAA spontaneous contrast; the majority (six of seven) had evidence of thrombus. We concluded that the LAA is a dynamic structure in which TEE study identified three flow patterns with different implications. AF is associated with two LAA flow types (II and III) with a larger LAA size as well as a higher incidence of LAA clots in type III flow.     

Left atrial appendage function and abnormal hypercoagulability in patients with atrial flutter

STUDY OBJECTIVES: The prevalence of thromboembolism might be higher than previously recognized in patients with atrial flutter (AFL) based on findings of transesophageal echocardiography (TEE). To evaluate the potential prothrombotic state in patients with AFL, TEE findings and hemostatic markers were compared among patient groups with AFL, normal sinus rhythm (NSR) and chronic nonvalvular atrial fibrillation (AF). DESIGN AND SETTINGS: Cross-sectional study at a university hospital. METHODS: In 28 patients (mean age, 63 years) with AFL, 58 patients (mean age, 66 years) with AF, and 27 patients (mean age, 61 years) with NSR who underwent TEE, plasma levels of markers for platelet activity (platelet factor 4 and beta-thromboglobulin [beta-TG]), thrombotic status (thrombin-antithrombin III complex and prothrombin fragments 1 and 2) and fibrinolytic status (d-dimer and plasmin-alpha(2)-plasmin inhibitor complex) were determined. RESULTS: Left atrial appendage (LAA) blood flow velocity in patients with AFL was higher (p < 0.05) than that in patients with AF, but was lower (p < 0.05) than that in patients with NSR (AF, 25 +/- 2; AFL, 44 +/- 4; NSR, 60 +/- 4 cm/s). Dense left atrial spontaneous echo contrast (SEC) was found in 4 patients (14%) with AFL and 16 patients (28%) with AF. There was no significant difference in plasma levels of hemostatic markers between the AFL group and the NSR group. AFL patients with impaired LAA function (LAA flow < 30cm/s, dense SEC, or both), however, showed higher level of d-dimer and beta-TG than those without impaired LAA function (d-dimer, 1.9 +/- 0.6 microg/mL vs 0.4 +/- 0.1 microg/mL; beta-TG, 73 +/- 17 ng/mL vs 33 +/- 5 ng/mL, p < 0.05). CONCLUSIONS: Patients with AFL as a whole are not in the prothrombotic state as compared with those with AF. However, patients with AFL and impaired LAA function are at potentially high risk for thromboembolism and might require anticoagulation.     

The feasibility of tissue Doppler acceleration as a new predictor of thrombogenesis in the left atrial appendage associated with nonvalvular atrial fibrillation

BACKGROUND: Tissue acceleration utilizing the tissue Doppler imaging (TDI) technique is a new marker of ventricular contraction. We evaluated whether the left atrial appendage (LAA) wall acceleration was associated with thrombosis in patients with nonvalvular atrial fibrillation (NVAF). METHODS: Seven NVAF patients with thromboembolism (TE), eight without TE, and eight with normal sinus rhythm (NSR) were studied using transesophageal echocardiography. TDI was used to evaluate the LAA wall acceleration. RESULTS: There was a decrease in the peak flow velocity in the TE group compared with the other two groups. There was greater LAA expansion in NVAF with TE groups (with TE [8.9 +/- 2.1 cm(2)] compared with the group without TE [7.3 +/- 2.8 cm(2)]), but the difference was not statistically significant; the difference was statistically significant compared with the NSR group (5.3 +/- 1.2 cm(2); P = 0.0035). The average of the continuous 40-frames area where tissue Doppler acceleration (TDA) was >0.024 cm/sec(2) was significantly lower in the TE group (0.12 +/- 0.05 cm(2)) compared to the group without TE (0.33 +/- 0.17 cm(2); P = 0.0017) and NSR group (0.30 +/- 0.13 cm(2); P = 0.0042), although wall velocity was not significantly different comparing the two NVAF groups. Furthermore, peak flow velocity of LAA was well correlated with LAA wall acceleration (r = 0.864, P < 0.0001). CONCLUSIONS: LAA wall acceleration obtained utilizing the TDI technique may be a new predictor of thrombogenesis in patients with NVAF.     

Left atrial appendage flow in nonrheumatic atrial fibrillation : relationship with pulmonary venous flow and ECG fibrillatory wave amplitude

OBJECTIVE: This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG. BACKGROUND: Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF. MEASUREMENTS AND RESULTS: Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile. CONCLUSION: In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.     

Prediction of successful cardioversion and maintenance of sinus rhythm in patients with lone atrial fibrillation

OBJECTIVE: We aimed to prospectively investigate the predictive value of echocardiographic parameters for the prediction of successful cardioversion and long-term sinus rhythm (SR) maintenance in patients who have experienced a lone episode of atrial fibrillation (AF). MEASUREMENTS AND RESULTS: Clinical and echocardiographic data, including mean left atrial appendage (LAA) peak flow velocity and mitral annulus motion, were analyzed in 78 consecutive patients (mean [+/- SD] age, 59.3 +/- 9.3 years) with AF lasting > 48 h and < 6 months. Sixty-one patients (78%) underwent successful external electrical cardioversion, while the remaining remained in AF. At the 1-year follow-up, of the 61 patients who had successfully been converted to SR, 24 (39.3%) remained in SR. For predicting the success of the cardioversion, we used a model consisting of two variables. LAA flow velocity (> 20 cm/s) and left ventricular (LV) fractional shortening (> 30%) appear to be quite strong, yielding 83.3% correct results. For predicting the maintenance of SR, we used a model consisting of two variables. The absence of the early systolic abnormal mitral annulus motion and LAA flow velocity (> 20 cm/s) appears to be quite strong, yielding 84.6% correct results. LAA flow velocity only marginally enters the model, and, if removed, little predictive value is lost (dropping to 83.3%). Removing the early systolic abnormal mitral annulus motion variable, the prediction value drops significantly to 70.5%. CONCLUSION: LAA flow velocity combined with LV fractional shortening can predict the success of the conversion of AF to SR. Additionally, LAA flow velocity, combined with the analysis of mitral annulus motion before cardioversion, can predict the long-term maintenance of SR.     

Left atrial appendage dysfunction in chronic nonvalvular atrial fibrillation is significantly associated with an elevated level of brain natriuretic peptide and a prothrombotic state

The study tested the hypothesis that left atrial appendage (LAA) dysfunction in nonvalvular atrial fibrillation (NVAF) correlates with a prothrombotic state, and investigated whether the plasma natriuretic peptides are marker of LAA dysfunction in NVAF. Sixty-seven patients underwent transthoracic and transesophageal echocardiography. The left ventricular fractional shortening, left atrial diameter (LAD), LAA flow velocity and the grade of spontaneous echo contrast (SEC) were determined. The plasma concentrations of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), D-dimer, and thrombin-antithrombin III complex (TAT) were measured. The patients were divided into 2 groups according to LAA flow velocity: group I (LAA velocity <20 cm/s) and group II (LAA velocity > or = 20cm/s). The SEC score, D-dimer, TAT, BNP and LAD were significantly increased in group I. Based on simple linear regression analysis, SEC score (r=-0.638), LAD (r=-0.493), D-dimer (r = -0.485), BNP (r = -0.463), TAT (r = -0.455) and age (r = -0.314) were inversely correlated with LAA flow velocity. Multivariate analysis showed that SEC score (p = 0.0014) and plasma BNP level (p=0.0075) were independent negative predictors for LAA flow velocity. In conclusion, LAA dysfunction is associated with a prothrombotic state, and the plasma BNP concentration may serve as a determinant of LAA function in NVAF.     

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

AIMS: 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. METHODS AND RESULTS: 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. CONCLUSION: 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.     

Effect of cardiac resynchronization therapy on left atrial appendage function and pulmonary venous flow pattern

BACKGROUND: Previous studies have shown improvement in left ventricular function and development of the reverse remodeling in the left ventricle and left atrium after cardiac resynchronization therapy (CRT). The aim of this study was to investigate the effect of CRT on left atrial appendage (LAA) function and pulmonary venous flow pattern. METHODS: Eighteen patients with systolic heart failure and complete left bundle branch block underwent implantation of biventricular pacemaker devices. In order to follow changes in LAA, transthoracic and transesophageal echocardiographic examinations were performed 1 week before and repeated 1 and 6 months after pacemaker implantation. RESULTS: CRT resulted in significant clinical improvement and decrease in NYHA functional class in 17 patients (94%). Maximum and minimum areas of left atrial appendage (LAAAmax and LAAAmin) decreased, with a concomitant increase in LAA ejection fraction. [LAAAmax: from 4.6+/-2 to 4.2+/-1.8 cm2 at the first (P < 0.001) and to 4.0+/-1.8 cm2 at the sixth month (P < 0.001); LAAAmin: from 2.7+/-1.3 to 2.3+/-1.2 cm2 at the first (P < 0.001) and to 2.2+/-1.2 cm2 at the sixth month (P < 0.001) and LAA ejection fraction: from 41+/-12% to 46+/-10% at the first (P = 0.007) and to 47+/-8% at the sixth month (P = 0.003)]. LAA active emptying and filling flow and pulmonary venous systolic velocities also increased after CRT. The appendage active emptying velocity correlated significantly with left ventricular ejection fraction (r = 0.50, P = 0.002), LAA ejection fraction (r = 0.51, P = 0.002), left atrial maximal volume, LAVmax (r = -0.44, P = 0.007), left atrial minimal volume, LAVmin (r = -0.50, P = 0.002) and pulmonary vein systolic flow velocity (r = 0.33, P = 0.05). CONCLUSION: Treatment of heart failure by CRT results with marked improvements in LAA function and increases pulmonary venous systolic velocity.     

Right atrial appendage function in patients with chronic nonvalvular atrial fibrillation

To assess right atrial appendage (RAA) flow and its possible relationship to left atrial appendage (LAA) flow in chronic nonvalvular atrial fibrillation (AF), transesophageal echocardiography (TEE) was performed in 26 patients with chronic nonvalvular AF (group I). For the purpose of comparison, an additional group of 27 patients with chronic valvular AF due to mitral stenosis (group II) was analyzed. The clinically estimated duration of AF in group I was significantly longer than that of group II (8.7+/-3.4 versus 2.7+/-1.1 years). Although right atrial size and RAA maximal area were larger in group I than those in group II, left atrial size was larger in group II than that in group I. Group II had larger LAA maximal areas than group I, but this difference did not reach statistical significance. The two groups were not different with respect to the RAA or LAA emptying velocities. Significant correlations were observed between echocardiographic parameters of the two atria in patients with nonvalvular AF (r range, 0.4 to 0.7). In contrast, in patients with valvular AF, no correlation was observed between the echocardiographic parameters of the two atria (appendage emptying velocity, r = 0.38, p = 0.051; atrial size, r = -0.03, p = 0.89; maximal appendage area, r = 0.07, p = 0.75, respectively). There were no significant differences in the presence of right and left atrial spontaneous echo contrast and thrombus between the groups. All of the right and left atrial thrombi were confined to their respective appendages and were found in the atria with spontaneous echo contrast. Both RAA and LAA thrombi were present in one patient. In conclusion, our findings suggest that AF could affect both atria equally in nonvalvular AF, in contrast to valvular AF. Therefore, the assessment of RAA function as well as LAA may be important in patients with chronic nonvalvular AF.     

Left atrial appendage function in prediction of paroxysmal atrial fibrilation in patients with untreated hypertension

The onset of AF results in a significant increase in mortality rates and morbidity in hypertensive patients and this rhythm disorder exposes patients to a significantly increased risk of cerebral or peripheral embolisms. Tissue Doppler imaging was found to be useful in early detection of myocardial dysfunction in several diseases. It was shown that tissue Doppler analysis of the walls of the left atrial appendage (LAA) can give accurate information about the function of the LAA in hypertensive patients. In this study, we aimed to investigate and identify the specific predictive parameters for the onset of AF in patients with hypertension with tissue Doppler imaging of LAA. We studied age and sex matched 57 untreated hypertensive patients with paroxysmal atrial fibrillation (PAF) and 27 untreated hypertensive subjects without PAF. With transthoracic echocardiography, diastolic mitral A-velocity and LA maximal volume index which reflects reservoir function of left atrium was measured, with transesophageal echocardiography, LAA emptying velocity (LAA-PW D2) and tissue Doppler contracting velocity of LAA (LAA-TDI-D2) were measured. LA maximal volume index of the groups (22.28?±?3.59?mL/m² in Group 1 versus 20.37?±?3.97?mL/m² in Group 2, p?=?0.07) and diastolic mitral A-velocity [0.93 (0.59–1.84) m/s in patients with PAF versus 0.90 (0.62–1.76) m/s in patients without PAF, p?=?0.26] was not significantly different between study groups, during TEE, LAA-PW D2 (0.31?±?0.04?m/s in Group 1 versus 0.33?±?0.03?m/s in Group 2, p?=?0.034) and LAA-TDI-D2 (0.18?±?0.04?m/s in Group 1 versus 0.21?±?0.05?m/s in Group 2, p?=?0.014) were significantly decreased in Group 1. In this study, we found that in hypertensive PAF patients despite normal global LA functions, LAA contracting function was deteriorated. Tissue Doppler analysis of LAA is clinically usefull approach to detect the risk of developing PAF in hypertensives.     

Predictors of left atrial spontaneous echocardiographic contrast or thrombus formation in stroke patients with sinus rhythm and reduced left ventricular function

The objective of the present study was to identify predictors of left atrial spontaneous echocardiographic contrast (SEC) or thrombus in patients with stroke with sinus rhythm and left ventricular dysfunction. Of 500 consecutive patients with stroke, 48 with sinus rhythm and reduced left ventricular ejection fractions (EFs) < or =45% were examined. Ten patients presented with SEC or thrombus. The patients with SEC or thrombus had larger left atrial diameters (47 +/- 4 vs 42 +/- 6 mm, p <0.05), smaller EFs (30 +/- 9% vs 38 +/- 8%, p <0.01), and slower left atrial appendage (LAA) flow velocities (42 +/- 13 vs 61 +/- 17 cm/s, p <0.01). Multivariate analysis identified EF < or =35% and LAA flow velocity < or =55 cm/s as predictors of SEC or thrombus (p <0.05). Patients with stroke with sinus rhythm and moderate- to high-grade reduction of the left ventricular EF represent a risk group for a left atrial source of embolism and should undergo transesophageal echocardiography.