Left Atrial Appendage Flow Research Articles

Mitral annular velocity by Doppler tissue imaging for the evaluation of atrial stunning after cardioversion of atrial fibrillation

Atrial and/or appendage stunning (AS) usually occur after successful cardioversion of atrial fibrillation (AF). Several parameters except mitral annular velocity were previously evaluated to determine AS. We investigated whether mitral annular velocity was useful for determining of AS. This study consisted of 52 consecutive patients with AF <3 months who converted to the sinus rhythm. Mitral inflow and annular velocities were measured before and after cardioversion. Left atrial appendage (LAA) size and flow were assessed. The average velocity of septal and lateral segments of mitral annulus was considered as the final annular velocity. Thrombus and/or spontaneous echo contrast (SEC) were also investigated. Of 52 patients, 29 (56%) had AS but 23 did not. There was no significant difference in age, gender, and cardioversion type between two groups. Hypertension was more prevalent in patients without AS compared to those with AS (P = 0.02). Mitral annular systolic and E-wave velocities were comparable in both groups (P > 0.05). Mitral annular A-wave velocity (3.1 +/- 2.9 vs. 7.1 +/- 2.2 cm/s, P < 0.001), and its velocity-time integral (0.27 +/- 0.22 vs. 0.74 +/- 0.19 cm, P < 0.001) were significantly lower in patients with AS compared with those without AS. The annular A-wave velocity < or =3.3 cm/s predicted AS with a sensitivity of 59% and specificity of 76%. It was correlated with mitral inflow A velocity (r = 0.85, P < 0.001), LAA emptying velocity (r = 0.41, P = 0.003) and presence of SEC (r = -0.52, P < 0.001). After cardioversion of AF, mitral annular A-wave velocity may be a new marker to determine AS.

Usefulness of Intensity Variation in the Left Atrial Appendage With Contrast Echocardiography to Predict Ischemic Stroke Recurrence in Patients With Atrial Fibrillation

The left atrial appendage (LAA) is 1 of the common thromboembolic sources in patients with atrial fibrillation (AF) with stroke. The aim of this study was to examine the usefulness of LAA opacification seen on contrast echocardiography for predicting stroke recurrence in patients with AF. In 192 patients with stroke with AF who underwent transesophageal echocardiography within 7 days after the onset, intracardiac intensity variation at the orifice of the LAA just after intravenous infusion of Levovist (1,500 mg) was measured. During a mean follow-up of 450 days, the association between LAA intensity variation and recurrence of cerebrovascular events was assessed. LAA intensity variation was markedly lower in 19 patients with stroke recurrence than 173 patients without stroke recurrence (8.1 +/- 4.7 vs 12.1 +/- 5.1 dB; p <0.001). LAA thrombus-negative patients with low LAA intensity variation (< or =9.2 dB; n = 45) had higher cerebrovascular recurrent event rates than those with high LAA intensity variation (>9.2 dB; n = 109; 20.0% vs 3.7%; p <0.001) and thrombus-positive patients (15.8%). Cox multivariate hazard analysis showed that of routine echocardiographic parameters, decreased LAA intensity variation was the only independent predictor of stroke recurrence (hazard ratio 5.244, p <0.01). In conclusion, LAA intensity variation on contrast transesophageal echocardiography is a new sensitive index for LAA flow stagnation and recurrent cerebrovascular events in patients with AF with stroke.

Mitral valve replacement impairs the flow in the left atrial appendage in mitral regurgitation

Objective — We aimed to assess the left atrial appendage (LAA) flow velocities of rheumatic valves in 46 patients, diagnosed with isolated mitral regurgitation (MR) (16 patients), mitral stenosis (MS) (14 patients) and combined MS and MR (MS + MR) (16 patients) before and after operation.Methods — The patients were subdivided into two groups, according to rhythm: sinus (SR) (20 patients) and atrial fibrillation (AF) (26 patients).All patients underwent transthoracic and transoesophageal echocardiography before and after the operation.Results — Preoperatively LAA flow velocities were the best in the MR group among the three groups. Postoperatively there was no statistically significant difference between the MR group and the other two groups for mean peak emptying and filling velocities in patients with SR and AF.The incidence of spontaneous echo contrast (SEC) and thrombus significantly increased in the MR group after operation.Thrombus was only seen in patients with AF at the postoperative period.Conclusions — Mitral valve replacement disturbs LAA flow velocities and increases the risk of thrombus formation in patients with MR.This risk was more obvious in cases with AF. Impaired left atrial appendage flow velocities increase the risk of thrombus formation.We recommend close follow-up for the increased possibility of thrombus formation in patients who had MR preoperatively and AF postoperatively.

Transthoracic Doppler echocardiography for the assessment of left atrial appendage size and blood flow velocity. A multicentre study

The aim of this study was to evaluate the reliability of transthoracic Doppler echocardiography (TTE) in the assessment of left atrial appendage (LAA) size and function. We considered 86 consecutive patients [56 male, 30 female; mean age 64 +/- 13 years, sinus rhythm 36 patients (42%); atrial flutter/fibrillation 50 patients (58%)] referred for transoesophageal echocardiography (TEE) and TTE. Maximum LAA transverse diameters and LAA peak flow velocities were calculated by two-dimensional and pulsed-wave Doppler analysis at TEE and TTE. LAA systolic transverse diameters were detectable in 78 patients (91%) by TTE and showed a significant correlation with TEE (r = 0.77, P < 0.0001). LAA peak flow velocities were measurable by TTE in 72 patients (84%) and were comparable with TEE (50.4 +/- 23 vs 47.3 +/- 23.2 cm/s, r = 0.67, P < 0.0001). A peak blood flow velocity of <25 cm/s at TTE was the best indicator of very low (<20 cm/s) LAA flow velocity as detected by TEE (sensitivity 93%, specificity 87%, area under the curve 0.94, P < 0.0001). Conversely, a peak blood flow velocity of >56 cm/s at TTE indicated a very high (> 40 cm/s) LAA flow velocity as detected by TEE (sensitivity 50%, specificity 96%, area under the curve 0.87; P < 0.0001). Reliable LAA size and blood flow velocities can be obtained by TTE in consecutive, unselected patients. TTE identifies patients with low and high blood flow velocities in the LAA, providing helpful information for the definition of individual embolic risk.

Relation of left atrial blood stasis to clinical risk factors in atrial fibrillation

Background The present study was conducted to investigate whether an accumulation of clinical risk factors for thromboembolism would correlate with severity of blood stasis in the left atrium (LA) and aortic atherosclerosis in patients with nonvalvular atrial fibrillation (NVAF). Methods Risk levels of thromboembolism were assessed in 515 (mean age 67.5 years) NVAF patients using CHADS 2 score (an acronym for Congestive heart failure, Hypertension, Age ≥ 75, Diabetes mellitus, and prior Stroke or transient ischemic attack) to estimate the thromboembolic risk. Spontaneous echocardiographic contrast in the LA (LASEC), left atrial appendage (LAA) peak flow velocity, and severity of atherosclerosis in the descending aorta were determined with transesophageal echocardiography. Results LASEC was significantly increased, and LAA flow velocity significantly decreased in correlation with an increase in the risk levels, as evaluated by CHADS 2 score ( p < 0.001). Severity of aortic atherosclerosis also increased in correlation with an increase in the risk levels ( p < 0.001). Even at the comparable risk level, patients with chronic atrial fibrillation (AF) ( n = 268) had higher LASEC ( p < 0.001) and lower LAA flow velocity ( p < 0.001) than those with paroxysmal AF ( n = 52) who were in AF rhythm at the time of echocardiographic investigation. Conclusion Severity of blood stasis in the LA and aortic atherosclerosis correlates with an accumulation of clinical risk factors for thromboembolism in NVAF patients. Additionally, the severity of blood stasis in the LA was greater in chronic AF patients than in paroxysmal AF patients at the comparable risk level.

Do the Left Atrial Substrate Properties Correlate with the Left Atrial Mechanical Function? A Novel Insight from the Electromechanical Study in Patients with Atrial Fibrillation

The atrial substrate is the determinant of occurrence and maintenance of atrial fibrillation (AF), which can induce remodeling of atrial function and structure. This study investigated the relationship between the left atrial (LA) substrate properties and LA mechanical function. Forty-four consecutive patients (50.3 +/- 10.7 years old, 33 men) who presented with sinus rhythm during echocardiographic study before receiving catheter ablation for AF were enrolled. The LA diameter, LA volume, ratio of early and late transmitral filling flow velocities (E/A), LA appendage flow velocity, and transmitral velocity-time integral (VTI) were measured by the echocardiography. The LA empty fraction (LAEF), which was obtained via dividing the difference between maximal and minimal LA volume by maximal LA volume, was calculated as a parameter of the global LA contractile function. The LA global contact voltage mapping (NavX system) was performed before pulmonary vein isolation. Mean LA voltage and LA low voltage zone index (LVZ index, area with voltage < 0.5 mV, divided by total LA surface area) showed significant correlation with LA diameter and volume, but only the LA LVZ index showed significant correlation with A-wave velocity, transmitral A-wave VTI, and LAEF (r =-0.340, -0.411, -0.426; P = 0.024, 0.006, 0.005, respectively). We divided the LA LVZ index into three groups (< 10%, 10-20%, > 20%). The LAEF got worse and the transmitral A-wave VTI percentage (divided by transmitral VTI) decreased as LA LVZ index increased. The LA substrate properties showed close correlation with LA size, but only the LA LVZ index correlated with the LA mechanical function.

Reduced left atrial appendage flow velocity is associated with the higher fibrinogen and d-dimer levels in patients with chronic atrial fibrillation

Reduced left atrial appendage flow velocity is associated with the higher fibrinogen and d-dimer levels in patients with chronic atrial fibrillation

Relationship between left atrial spontaneous echo contrast density and left atrial appendage flow velocity in chronic atrial fibrillation

surgical or interventional procedures for RMVD were also excluded from the study. Patients were randomized into 2 groups 3 weeks before EC with adding amiodarone (group I, n = 66) or amiodarone plus ramipril (group II, n = 67) to their ordinary medication (amiodarone therapy, 600 mg/d for 7 days as initial loading dose and 200 mg/d for following days; ramipril therapy, 5 mg/d as initial dose and increased to 10 mg/d until EC if tolerated). The duration of follow-up was 1 year, and recurrence of AF was defined as the study end point. Results: The treatment groups had similar demographic and baseline characteristics (Table 1). Kaplan-Meier analysis demonstrated that the probability of remaining in sinus rhythm at 1 year was not different between the 2 groups (Figure). Conclusions: We could not find any favorable effect of ramipril, which was added to amiodarone after successful EC in patients with RMVD. The using of ACEI may not be effective on reducing the recurrence of AF in RMVD.

High risk of cardiogenic cerebral embolism for very elderly patients in sinus rhythm with left atrial appendage flow velocity below 50 cm/s

Recent clinical trials have demonstrated that patients in sinus rhythm after cardioversion are still at risk of suffering from embolic events, but the precise mechanisms underlying the occurrence of cardiogenic cerebral embolism remain to be determined. All 72 patients aged 75 or over who were consecutively referred to our department between October 2003 and March 2006 were divided into three groups; these were: group 1, 17 patients in sinus rhythm after cardioversion; group 2, 18 patients without any history of atrial fibrillation; and group 3, 37 patients with chronic atrial fibrillation. Using transesophageal echocardiography, we evaluated the left atrial appendage flow velocity, left atrial appendage dimension, spontaneous echocardiographic contrast in the left atrium, and the presence of thrombus in the left atrial appendage. Left atrial appendage flow velocity was significantly lower in group 1 compared with group 2 (38.2 ± 6.1 vs 61.4 ± 7.4 cm/s, P &lt; 0.001), but was even lower in group 3 (25.1 ± 9.8 cm/s, P &lt; 0.001 vs group 1). Spontaneous echocardiographic contrast in the left atrium, thrombus in the left atrial appendage and cardiogenic cerebral embolism showed a close relationship with left atrial appendage flow velocity, and were more frequent when left atrial appendage flow velocity was less than 50 cm/s. Very elderly patients in long‐term maintenance of sinus rhythm with an left atrial appendage flow velocity of less than 50 cm/s would have a high risk of cardiogenic cerebral embolism.

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.

Pulmonary Venous Flow Assessed by Doppler Echocardiography in the Management of Atrial Fibrillation

Pulmonary venous blood flow (PVF) visualized by Doppler echocardiography exhibits a pulsatile behavior, which is related to left atrial pressure and function, mitral valve function, and left ventricular compliance. In atrial fibrillation (AF), the disappearance of atrial reverse flow, a decrease in systolic flow with a greater diastolic than systolic flow, a prolonged onset of systolic flow and the appearance of an early systolic reverse flow are characteristic findings. A reduction in systolic PVF expressed by reduced peak velocity, reduced velocity-time integral of systolic flow, and reduced systolic fraction of PVF has been found to be associated with reduced left atrial appendage flow, left atrial spontaneous echo contrast formation, frequency of AF paroxysms and propensity for AF recurrence following restoration of sinus rhythm. Ablation techniques targeting pulmonary vein ostia and adjacent left atrium are promising treatment options to cure AF. Monitoring the PVF response to and adjusting of ablation procedures has been suggested to optimize outcome and prevent complications such as pulmonary vein stenosis. In conclusion, assessment of PVF variables and patterns by Doppler echocardiography seems useful in the management of AF patients. Especially the reduction in systolic PVF may be used as marker for left atrial dysfunction which favors thrombus formation and AF reinitiation. Finally, PVF monitoring has the potential to an increasing role in AF ablation procedures.

Dual‐Site Right Atrial Pacing Increases Left Atrial Appendage Flow in Patients with Sick Sinus Syndrome and Paroxysmal Atrial Fibrillation

Dual-site right atrial pacing has been proposed as a promising concept for prevention of paroxysmal atrial fibrillation (PAF). Effects of this pacing configuration on left atrial appendage (LAA) flow and transmitral flow may be of prognostic and hemodynamic relevance. This study aims to characterize acute changes in left atrial flow depending on dual-site right atrial pacing. In 12 patients (66 +/- 8.8 years, 4 women) with PAF and sinus bradycardia a pacemaker with a right atrial dual-site lead configuration (right atrial lateral and coronary sinus ostium) was implanted. Flow velocities in the left pulmonary vein (LPV), LAA, and across the mitral valve were assessed by transesophageal echocardiography and compared during sinus rhythm (SR) and dual-site (DS) pacing. Dual-site pacing resulted in higher maximum (SR: 0.57 m/s; pacing: 0.77 m/s; P < 0.02) and mean (SR: 0.33 m/s; DS: 0.47 m/s; P < 0.01) LAA emptying flow when compared with SR. The passive transmitral flow component (maximum E-wave velocity) was lower during dual-site pacing (SR: 0.53 m/s vs DS: 0.44 m/s, P < 0.02). The E/A ratio tended to be lower during dual-site pacing (SR: 1.21 vs DS: 1.01, P = 0,10). LPV flow velocities during SR and DS pacing did not differ. DS right atrial stimulation in patients with PAF increases the LAA emptying flow velocity and shifts the transmitral flow pattern towards a lower passive component when compared with sinus rhythm. The change in LAA flow may contribute to a lower incidence of thromboembolism and merits further investigation.

247 Doppler-echo evaluation of left atrial and ventricular function after circumferential RF catheter ablation of pulmonary veins due to paroxysmal and persistens atrial fibrillation. A prospective 5 m

Background: Hemodynamics of isolated atrial fibrillation (AF) has not been widely investigated, but it is belived to be associated with slight enlargement of left atrial (LA) size and minor degree of left ventricular (LV) diastolic dysfunction, that is presumed rather to be a result than a cause of so called „lone AF”. Positive impact of sinus rhythm restoration by catheter ablation on LA size and LV function remains unclear. Aims: To evaluate the possible reverse remodeling of LV and LA after successful ablation procedure of AF and its relationship with arrhythmia recurrence in prospective 5 months follow-up study with transthoracal and transesophageal echocardiographic examination (TTE and TEE). Methods and results: Sixty two patients, with refractory to antiarrhyhtmic agents and highly symptomatic episodes of paroxysmal and persistent AF underwent circumferential pulmonary vein RF catheter ablation according to Pappone technique. 3-dimensional electroanatomic CARTO system was used. In all patients TTE and TEE was performed before and 5±3 months after procedure, in order to assess LA area and left atrial appendage (LAA) area and flow as well as certain systolic/diastolic LV function parameters (mitral flow A/E ratio, E-wave deceleration time, Tei index, ejection fraction). The influence of LA and LV function parameters change on maintenance of sinus rhythm was studied and conversely, the impact of sinus rhythm restoration on LA and LV function. Seventeen patients reported symptoms of arrhythmia, whereas 45 remained AF free. There were nether clinical nor echocardiographic baseline data determining ablation success rate. We found significant difference as far as LVEF was concerned before and after ablation procedure (62±3%, 64±4%; p<0.01), with no significance but still a positive trend (p=0.06) in a subgroup presenting with no arrhythmia recurrence at follow-up. We found evident correlation between certain, but not all LV systolic/diastolic parameters at the time of follow-up and the recurrence of arrhythmia. The most significant parameter for arrhythmia recurrence in our study was Tei index, that deteriorated significantly in patients with unsuccessful ablation. Conclusions: Five months follow-up after CPVI, with echo performance shows good clinical results, with significant improvement of some but not all LV systolic/diastolic function parameters.

Evaluation of Atrial Thrombus Formation and Atrial Appendage Function in Patients with Pacemaker by Transesophageal Echocardiography

Physiologic pacing is claimed to be superior to ventricular pacing in as much as it entails lower risk of atrial fibrillation, stroke, and atrial remodeling. There are few data on the relation between atrioventricular (AV) synchrony and atrial clot formation. Utilizing transesophageal echocardiography (TEE), this study sought to evaluate the effect of AV synchrony loss on left atrial physiology, atrial stasis, and clot formation. We conducted a cross-sectional study on patients with both AV and ventricular pacing with left ventricular ejection fraction (LVEF) >30%. TEE enabled us to explore atrial and pacing leads thrombi and measure left atrial appendage (LAA) flow velocity. A total 72 patients (mean age, 65 +/- 11.7) were enrolled in the study. The pacing mode was VVI in 53% and AV sequential in 47% of patients. LVEF (mean +/- SD; %) was 53.3 +/- 6.2% in ventricular pacing mode and 52.2 +/- 6.6 in physiologic pacing mode. Thrombus formation on pacing lead (<10 mm in 97% of patients) was observed in 32% of all the patients (23% in patients with AV sequential pacing mode and 39% with VVI mode). Left atrial appendage flow velocity (LAA-FV) was significantly higher among the patients with AV sequential pacing mode (49.44 +/- 18 cm/s vs 40.94 +/- 19.4 cm/s, P value = 0.02). LAA-FV >40 cm/s was detected in 60% of the patients, 60% of whom were in physiologic mode. Left atrial size was significantly larger among the patients with VVI pacing mode (42.3 +/- 2.3 mm vs 37.79 +/- 4.5 mm, P = 0.001). Multivariate analysis showed no relation between LAA-FV and age, hypertension, diabetes mellitus, left atrial size, and left ventricular function. Only one patient had right atrial clot. There was no thrombus in the ventricles and atrial appendage. Long-term loss of AV synchrony induced by VVI pacing is associated with the impairment of LAA contraction. Thrombus formation in the LAA is not increased by VVI pacing in patients with relatively good left ventricular (LV) function and sinus rhythm.

Left Atrial Appendage Function in Patients with Systemic Embolism in Spite of in Sinus Rhythm

We sought to investigate whether left atrial (LA) appendage (LAA) function was impaired in patients with systemic embolism in sinus rhythm. Transesophageal echocardiography was performed in 7 patients within 5 days after embolism (early group) and in 32 patients, more than 5 days after embolism (late group). We searched intracardiac thrombus and determined LAA area and LAA flow velocity, and the grade of spontaneous echocontrast. LA thrombus could be detected in 2 of the 39 patients only in early group (P = .028). The patients of early group, as compared with late group, had lower LAA flow velocity (28 +/- 16 vs 60 +/- 26 cm/s, P = .007) and higher grade of spontaneous echocontrast score (1.14 +/- 1.46 vs 0.25 +/- 0.62, P = .013). LA dimension and LAA area were not statistically different. LAA function may be impaired early after embolism even in sinus rhythm.

Assessment of Left Atrial Appendage Flow Velocity and its Relation to Spontaneous Echocardiographic Contrast in 89 Cats with Myocardial Disease

The hypotheses of this prospective study were that (1) left atrial appendage (LAA) blood flow velocities can be recorded in cats with myocardial disease by transthoracic Doppler echocardiography, (2) LA enlargement, LA mechanical dysfunction, and left ventricular (LV) diastolic abnormalities are associated with decreased LAA flow velocities, and (3) low LAA flow velocities predict the appearance of spontaneous echocardiographic contrast in cats with cardiomyopathy. Transthoracic 2-dimensional, M-mode, and Doppler echocardiographic studies were performed in 89 cats with hypertrophic, restrictive, dilated, or unclassified cardiomyopathy or with hyperthyroid heart disease. Maximal LAA flow velocity (LAAmax) was decreased (P < .001) in cats with cardiomyopathy (median, 0.28 m/s; range, 0.08-1.35) compared to normal cats. Associated with decreased LAA flow velocities were increased LA size, decreased LA function, increased severity of LV diastolic dysfunction, and the presence of congestive heart failure. Multivariate logistic regression analysis detected an LAAmax <0.20 m/s as the only independent variable to predict LA spontaneous echocardiographic contrast (odds ratio, 30.1; 95% confidence interval [CI], 4.1 222.3; P < .001). Receiver operating characteristic analysis performed to predict spontaneous echocardiographic contrast indicated an area under the curve of 0.88 (95% CI, 0.80-0.95; P < .001) with sensitivities of 100 and 74% and specificities of 69 and 83% for LAAmax <0.25 and <0.20 m/s, respectively. Thus, low LAA flow velocities identified a subgroup of patients at increased risk of spontaneous echocardiographic contrast and possible thromboembolism. These findings may have important clinical implications for anticoagulation therapy and prognostication in cats with cardiomyopathy.

Assessment of Left Atrial Appendage Flow Velocity and its Relation to Spontaneous Echocardiographic Contrast in 89 Cats with Myocardial Disease

The hypotheses of this prospective study were that (1) left atrial appendage (LAA) blood flow velocities can be recorded in cats with myocardial disease by transthoracic Doppler echocardiography, (2) LA enlargement, LA mechanical dysfunction, and left ventricular (LV) diastolic abnormalities are associated with decreased LAA flow velocities, and (3) low LAA flow velocities predict the appearance of spontaneous echocardiographic contrast in cats with cardiomyopathy. Transthoracic 2‐dimensional, M‐mode, and Doppler echocardiographic studies were performed in 89 cats with hypertrophic, restrictive, dilated, or unclassified cardiomyopathy or with hyperthyroid heart disease. Maximal LAA flow velocity (LAAmax) was decreased (P&lt; .001) in cats with cardiomyopathy (median, 0.28 m/s; range, 0.08‐1.35) compared to normal cats. Associated with decreased LAA flow velocities were increased LA size, decreased LA function, increased severity of LV diastolic dysfunction, and the presence of congestive heart failure. Multivariate logistic regression analysis detected an LAAmax&lt;0.20 m/s as the only independent variable to predict LA spontaneous echocardiographic contrast (odds ratio, 30.1; 95% confidence interval [CI], 4.1–222.3;P&lt; .001). Receiver operating characteristic analysis performed to predict spontaneous echocardiographic contrast indicated an area under the curve of 0.88 (95% CI, 0.80‐0.95;P&lt; .001) with sensitivities of 100 and 74% and specificities of 69 and 83% for LAAmax&lt;0.25 and &lt;0.20 m/s, respectively. Thus, low LAA flow velocities identified a subgroup of patients at increased risk of spontaneous echocardiographic contrast and possible thromboembolism. These findings may have important clinical implications for anticoagulation therapy and prognostication in cats with cardiomyopathy.

Higher Levels of Serum Fibrin-Monomer Reflect Hypercoagulable State and Thrombus Formation in the Left Atrial Appendage in Patients With Acute Ischemic Stroke

It is sometimes difficult to make a diagnosis of cardioembolic stroke in the stroke care unit, because of the splashing and vanishing of the intracardiac source of the emboli on transesophageal echocardiography. Serum fibrin-monomer (FM) is a new marker for coagulation activity that is useful for identifying older individuals at increased risk of ischemic stroke. Two hundred and four patients with acute ischemic stroke were examined for serum coagulation and fibrinolytic activity on admission, and underwent transesophageal echocardiography within 7 days of onset. Serum levels of FM was significantly higher in patients with left atrial appendage (LAA) thrombus formation (n=24) than in those with no thrombus (88+/-52 vs 14+/-9 microg/ml, p<0.0001). On multivariate logistic regression analysis, FM was an independent predictor for LAA thrombus (RR 2.975, 95% confidence interval 1.114 to 4.820, p=0.0214). In patients with LAA thrombus negative group, cases with LAA emptying flow velocity at atrial systole that was absent or smaller than at early diastole had significantly higher FM levels as compared to cases with larger velocity (42+/-12 vs 8+/-5 microg/ml, p<0.0001). Higher levels of serum FM reflect LAA flow pattern alterations and thrombus formation in patients with acute ischemic stroke.

Left Atrial Appendage-Flow Velocity Predicts Cardioversion Success in Atrial Fibrillation

Restoration of sinus rhythm by electrical cardioversion is a therapeutic option in appropriately selected patients with atrial fibrillation. It is important to determine predictors of electrical cardioversion outcome in patients with atrial fibrillation. Predictive value of clinical and conventional echocardiographic parameters for predicting cardioversion outcome is limited. The role of left atrial appendage (LAA) function, which may reflect left atrial contractile function, for prediction of cardioversion outcome remains unclear. We conducted a single center prospective study to evaluate the role of LAA function for prediction of cardioversion success in patients with atrial fibrillation. One hundred sixty three patients with atrial fibrillation underwent transthoracic and transesophageal echocardiography (TEE) before electrical cardioversion. LAA functions, including LAA peak flow velocity, LAA area and LAA ejection fraction, were examined. Cardioversion was successful in 133 patients and unsuccessful in 30 patients. Mean LAA peak emptying flow velocity was significantly higher in the patients with successful cardioversion than in those with unsuccessful cardioversion (0.34 +/- 0.14 vs 0.27 +/- 0.1 m/sec; p = 0.013). At multivariate logistic regression analysis, only LAA flow velocity (> 0.28 m/sec, odds ratio = 2.8 ; p = 0.03) proved to be an independent predictor of cardioversion success. LAA area (p = 0.18) and LAA ejection fraction (p = 0.52) were not different between successful and unsuccessful cardioversion groups. Therefore, measurement of LAA flow velocity provides valuable information for prediction of cardioversion outcome in patients with atrial fibrillation before TEE guided cardioversion.

Left Atrial Appendage Flow Velocity as a Quantitative Surrogate Parameter for Thromboembolic Risk: Determinants and Relationship to Spontaneous Echocontrast and Thrombus Formation–A Transesophageal Echocardiographic Study in 500 Patients with Cerebral Ischemia

Hemostasis in the left atrial (LA) appendage (LAA) is an important cause in the formation of thrombi. Determination of the LAA flow velocity (LAAV) could be a quantitative parameter for estimating thromboembolic risk. The objective of this study was to: (1) determine the relationship between LAAV and qualitative parameters with elevated thromboembolic risk (thrombus/spontaneous echocontrast [SEC]); and (2) define factors that influence LAAV. In all, 500 patients with stroke were examined consecutively by transesophageal echocardiography. In addition to measurement of the LAAV, the atrial appendage was examined for the presence of thrombi or SEC. LAAV differed significantly among patients with sinus rhythm (71 +/- 16 cm/s), paroxysmal atrial fibrillation (AF) and in sinus rhythm during transesophageal echocardiography (46 +/- 13 cm/s), paroxysmal AF and AF during transesophageal echocardiography (32 +/- 12 cm/s), and chronic AF (27 +/- 9 cm/s, P < .001). Independent of the rhythm, the risk of thrombus/SEC increased significantly at an LAAV less than 55 cm/s. At an LAAV 55 cm/s or more there is only a minimal risk of thrombus/SEC (negative predictive value 100% and 99%, respectively). Multivariate analysis showed that LAAV is the strongest predictor for the occurrence of thrombus/SEC (P < .0001). Further multivariate analysis showed that left ventricular ejection fraction, LA size, (paroxysmal) AF, age, and sex are independent parameters influencing LAAV. Independent of the basic rhythm, there is a close relationship between LAAV and qualitative parameters of elevated thromboembolic risk. LAAV could, therefore, be a quantitative surrogate parameter for risk stratification. It is influenced by both cardiac and extracardiac factors.