Left Atrial Appendage Flow Velocity Research Articles

Clinical and instrumental factors associated with sinus rhythm maintenance following direct current cardioversion of late persistent non-valvular atrial fibrillation at 6-months follow-up

Abstract Purpose To study the clinical and instrumental factors, associated with sinus rhythm (SR) maintenance following direct current cardioversion (DCCV) in patients with late persistent non-valvular atrial fibrillation (AF) at 6-months follow-up. Methods The cohort single-center study analyzed clinical and instrumental data from 59 late persistent AF patients (with duration of its episode ≥90 days [up to 12 months]), who underwent an elective DCCV. At 6-months follow-up, 32 (54 %%) patients succeeded to maintain SR, in contrast to 27 (46 %) patients with a failure to its maintenance. Results The univariate logistic regression analysis revealed, that the absence of heart failure (HF) stage C (i.e., the presence of its stage B), the higher left ventricular ejection fraction (LVEF) (by transthoracic echocardiography [TTE]), left atrial appendage flow velocity (LAAFV) >40 cm/s and the freedom from left atrial spontaneous echo contrast (LASEC) (by transesophageal echocardiography), ‒ all were associated with the higher chance to maintain SR at 6-months follow-up (Figure). At the same time, the higher baseline left atrial dimension (LAD) and more advanced pulmonary hypertension (PH) (by TTE) were associated with the failure of its maintenance to be more probable (Figure). At multivariate analysis, the following predictors of SR maintenance after DCCV at 6-months follow-up were identified: higher LVEF (OR 1,07 (95 % CI 1,01-1,13); р=0,021); LAAFV >40 cm/s (OR 4,33 (95 % CI 1,06-17,78); р=0,042), and less advanced PH (OR 0,24 (95% CI 0,06-0,93); р=0,038). Conclusion Better LV systolic function, LAAFV >40 cm/s and less advanced PH were the predictors of SR maintenance following DCCV in patients with late persistent (with duration of its episode ≥90 days) non-valvular AF at 6-months follow-up.

Validation of CT in comparison to TEE in routine workflow for detection of LAA thrombus in patients under oral anticoagulation presenting for left atrial ablation

Abstract Background Left atrial (LA) thrombus in patients (pts) presenting for LA ablation is an absolute contraindication to ablation. Although thrombi can still form despite the use of oral anticoagulation (OAC) in advance of the procedure. Transesophageal echocardiography (TEE) has been considered the gold standard for LAA thrombus detection. Additional cardiac computer tomography (CT) is often performed in pts with persistent atrial fibrillation (AF) or atrial tachycardia (AT). The aim of the study was in routine workflow 1) to identify the incidence of LAA thrombi in TEE and CT, 2) to search for an association in detecting LAA thrombi in the 2 methods and 3) to find out if the LAA flow velocity/ LA volume influences the thrombus detection. Methods Between 05/2018 and 10/2023 patients with AF/AT under OAC which were scheduled for a LA ablation were included. TEE and CT searching for LAA thrombus were carried out at intervals of up to 7 days. LAA flow velocity measured in the TEE. The LA volume which included LAA and excluded the pulmonary veins were obtained from the CT at the end-systole. Results Patients characteristics: 283 pts were included, mean age of 66y (+9y), 182 male, mean CHA2DS2-VASc score 3 [0-7]. All patients, mostly on NOACs (n=265), were orally anticoagulated. Mean LA volume (LA + LAA) was 158 ml (+45ml), LAA flow velocity was reduced (< 40 cm/s) in 119 pts (42%). In the majority of cases (73%), TEE and CT were performed at the same day or with an interval of 1 day. In 16 pts a LAA thrombus was detected using TEE,42 pts had SEC/Sludge but no solid thrombus. An LAA thrombus in the CT was described in 26 pts (10%), 6% couldn't definitively diagnose thrombi due to contrast recesses/flow phenomena in 16 pts. In 8 out of 34 events (23%) TEE and CT agreed on the diagnosis of a thrombus, in 6 cases during same-day examinations. 18 pts: LAA thrombus on CT, not on TEE (mean interval: 2d). 8 pts: LAA thrombus on TEE, not on CT (mean interval: 1.5d). In 71% (200 out of 283) of cases, CT and TEE agreed in ruling out a thrombus (p=0.358). LAA flow velocity and thrombus verification by TEE showed a significant correlation (p < 0.001). No correlation was found between the presence of a thrombus on CT and LA volume (p= 0.964). Discussion In 12% of the patients, all treated with OAC, a thrombus was described in at least one of the examinations or in both. Only in one out of four pts TEE and CT agreed on the diagnosis of a thrombus. It was notable that both examinations excluded thrombi in 70%. LAA flow velocity and thrombus verification in the TEE are significant correlated. LA volume and thrombus notification in CT are not related. Conclusion Routine diagnosis of LAA thrombus remains challenging, with frequent discrepancies between TEE, the gold standard, and CT. TEE results depend on the examining physician, while CT is limited by flow phenomena and scan timing.

Impact of left atrial appendage flow velocity on thrombus resolution and clinical outcomes in patients with atrial fibrillation and silent left atrial thrombi: insights from the LAT study.

Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear. The LAT study was a multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal echocardiography (TEE). Among 17 436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (P < 0.001). During 1 year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], P = 0.003). Despite limited predictive power (area under the curve, 0.659; P = 0.001), LAAFV ≤ 20.0 cm/s (best cut-off) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; P = 0.015). The incidence of adverse outcomes including ischaemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank P = 0.005). Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Proteomic biomarkers for noninvasive left atrial appendage thrombus prediction in patients with atrial fibrillation

IntroductionThe CHA2DS2-VASc score, used to assess the risk of left atrial appendage thrombus (LAAT) formation in patients with atrial fibrillation (AF), has limited predictive value. Moreover, transesophageal echocardiography imaging, the gold standard diagnostic method to identify thrombi, is semi-invasive. Consequently, there is a need for alternative and noninvasive diagnostic methods for LAAT risk assessment. MethodsDeep proteomic analysis was conducted in plasma samples from 8 patients with nonvalvular AF, divided into thrombus and control groups (4 patients in each group) based on the presence or absence of LAAT. Biomarkers associated with LAAT were validated using an enzyme-linked immunosorbent assay in a cohort of 179 patients with available clinical, transthoracic, and transesophageal echocardiography data. Predictive models were developed to assess the improvement in LAAT identification. ResultsThe LAAT group had higher CHA2DS2-VASc scores, larger LA diameter, and lower LAA flow velocities. Deep proteomic analysis identified 30 differentially expressed proteins, including myosin light chain 4, prenylcysteine oxidase 1 (PCYOX1), and decorin as potential diagnostic biomarkers of LAAT. The model showed that PCYOX1 and decorin provided an area under the curve (AUC) of 0.970 for LAAT prediction compared with 0.672 in a model including the CHA2DS2-VASc score and LAA cauliflower morphology. The incremental value of proteomic biomarkers for LAAT in patients with nonvalvular AF was further confirmed with the net reclassification improvement and integrated discrimination improvement indices. ConclusionsProtein levels of PCYOX1 and decorin improve the predictive performance for LAAT in patients with nonvalvular AF.

Safety and efficacy of the second-generation cryoballoon for left atrial appendage electrical isolation in canines.

Left atrial appendage electrical isolation (LAAEI) has demonstrated a significant enhancement in the success rate of atrial fibrillation (AF) ablation. Nevertheless, concerns persist about the safety of LAAEI, particularly regarding alterations in left atrial appendage (LAA) flow velocity and the potential risks of thrombus. This study aimed to assess the efficacy and safety of LAAEI, investigating changes in LAA flow velocity in canines. The study comprised a total of 10 canines. The LAAEI procedure used by a 23 mm cryoballoon of the second generation was conducted at least 180 s. Intracardiac ultrasonography (ICE) was employed to quantify the velocity flow of the LAA both prior to and following LAAEI. Following a 3-month period, subsequent evaluations were performed to assess the LAA velocity flow and the potential reconnection. Histopathological examination was conducted. Left atrial appendage electrical isolation was effectively accomplished in all canines, resulting in a 100% acute success rate (10/10). The flow velocity in the LAA showed a notable reduction during LAAEI as compared with the values before the ablation procedure (53.12 ± 5.89 vs. 42.01 ± 9.22 cm/s, P = 0.007). After the follow-up, reconnection was observed in four canines, leading to a success rate of LAAEI of 60% (6/10). The flow velocity in the LAA was consistently lower (53.12 ± 5.89 vs. 44.33 ± 10.49 cm/s, P = 0.006), and no blood clot development was observed. The histopathological study indicated that there was consistent and complete injury to the LAA, affecting all layers of its wall. The injured tissue was subsequently replaced by fibrous tissue. The feasibility of using cryoballoon ablation for LAAEI was confirmed in canines, leading to a significant reduction of LAA flow velocity after ablation. Some restoration of LAA flow velocity after ablation may be linked to the passive movement of the LAA and potential reconnecting. However, this conclusion is limited to animal study; more clinical data are needed to further illustrate the safety and accessibility of LAAEI in humans.

Association of Left Atrial Appendage Morphology and Function With Stroke and Transient Ischemic Attack in Atrial Fibrillation Patients

We aimed to correlate left atrial appendage (LAA) structure and function with the history of stroke/transient ischemic attack (TIA) in patients with atrial fibrillation (AF). We analyzed data of 649 patients with AF who were scheduled for catheter ablation. Patients underwent cardiac CT and transesophageal echocardiography prior to ablation. LAA morphologies depicted by cardiac CT were categorized into four groups: cauliflower, chicken wing, swan and windsock shapes. Mean age was 61.3±10.5 years, 33.9% were female. Prevalence of stroke/TIA was 7.1%. After adjustment for the main risk factors, LAA flow velocity ≤35.3 cm/sec (OR=2.18; 95%CI=1.09-4.61; p=0.033) and swan LAA shape (OR=2.69; 95%CI=0.96-6.86; p=0.047) independently associated with higher risk of stroke/TIA, while windsock LAA morphology proved to be protective (OR=0.32; 95%CI=0.12-0.77; p=0.017) as compared to cauliflower LAA shape. When comparing the differences between LAA morphology groups, we measured significantly smaller LAA orifice area (389.3±137.7 mm2 in windsock vs 428.3±158.9 ml in cauliflower, p=0.021) and LAA volume (7.4±3.0 mm2 in windsock vs 8.5±4.8 mm2 in cauliflower, p=0.012) in patients with windsock LAA morphology, while LAA flow velocity did not differ significantly. Reduced LAA function and swan LAA morphology were independently associated with higher prevalence of stroke/TIA, while windsock LAA shape proved to be protective. When comparing the differences between the various LAA morphology types, significantly lower LAA volume and LAA orifice area were measured in windsock LAA shape as compared to cauliflower LAA shape.

Associations of the left atrial epicardial fat thickness with the thrombosis prevalence and left atrial appendage flow velocity in patients with persistent non-valvular atrial fibrillation

Aim. To study the associations of the left atrial epicardial fat (LAEF) thickness with the thrombosis prevalence and left atrial appendage (LAA) flow velocity in patients with persistent non-valvular atrial fibrillation (AF).Material and methods. Transesophageal echocardiography in 475 patients with persistent non-valvular AF (men 58,9%, age 64,0 (58,3-70,0) years) assessed LAA flow velocity, interatrial septum and left lateral ridge thickness. Their average thickness was used to estimate the LAEF volume.Results. LAA thrombus was detected in 42 (8,8%) patients. LAA flow velocity without thrombus was 32,0 (26,0-39,0) cm/s, with thrombus — 20,0 (14,0-25,8) cm/s (p&lt;0,0001). Depending on the LAEF thickness, patients were divided into 3 tertile groups: group 1 (n=168) — 5,6-7,4 mm, group 2 (n=154) — 7,45-8,2 mm, group 3 (n=153) — 8,25-10,9 mm. In group 1, no thrombus was detected, in group 2, thrombus was detected in 2 (1,3%) patients, in group 3 — in 40 (26,0%) patients (p&lt;0,0001). In the absence of LAA thrombus, flow velocity in the selected groups did not differ (32,0 (26,0-39,0) cm/s, 31,0 (26,0-7,8) cm/s and 31,5 (25,0-40,0) cm/s, (p=0,9514)).Conclusion. EFL thickness, calculated as the average of interatrial septum and left lateral ridge thickness, can be used to study the relationship between epicardial obesity and LAA thrombosis in patients with AF. In patients with persistent non-valvular AF with a LAEF thickness &gt;8,2 mm, LAA thrombosis occurs more than 40 times more often than in patients with a lower LAEF thickness. The influence of LAEF thickness on LAA flow velocity was not revealed in the pre­sent study.

Impact of left atrial appendage thrombus location on diagnostic accuracy of cardiac CT: a single-centre case-control study

ObjectiveCardiac CT (CCT) is an emerging non-invasive modality for assessing left atrial appendage (LAA) thrombus, but the results were conflicting. Our study aims to evaluate the accuracy of CCT for...

Efficacy of Low-Dose Isoproterenol Infusion for the Exclusion of a Left Atrial Appendage Thrombus in Patients With Dense Spontaneous Echo Contrast Caused by Atrial Fibrillation.

In patients with atrial fibrillation (AF) and severe blood stasis in the left atrial appendage (LAA), dense spontaneous echo contrast (SEC) disturbs the distinct visualization of the LAA interior, thus making thrombus diagnosis inconclusive. We aimed to prospectively assess the efficacy and safety of a protocol for a low-dose isoproterenol (ISP) infusion to reduce SEC to exclude an LAA thrombus.Methods and Results: We enrolled 17 patients with AF and dense SEC (Grade 4 or sludge). ISP was infused with gradually increasing doses of 0.01, 0.02, and 0.03 μg/kg/min at 3-min intervals. After increasing the dose to 0.03 μg/kg/min for 3 min, or when the LAA interior was visible, the infusion was terminated. We reassessed the SEC grade, presence of an LAA thrombus, LAA function, and left ventricular ejection fraction (LVEF) within 1 min of ISP termination. Compared with baseline, ISP significantly increased LAA flow velocity, the LAA emptying fraction, LAA wall velocities, and LVEF (all P<0.01). ISP administration significantly reduced the SEC grade (median) from 4 to 1 (P<0.001). The SEC grade decreased to ≤2 in 15 (88%) patients, and the LAA thrombus was excluded. There were no adverse events. Low-dose ISP infusion may be effective and safe to reduce SEC and exclude an LAA thrombus by improving LAA function and LVEF.

Effect of epigenetic regulation on left atrial function and recurrence after catheter ablation in patients with atrial fibrillation

Abstract Background Genetic variation and modifiable risk factors play a significant role in the pathogenesis of atrial fibrillation (AF). However, the influence of epigenetic modification on AF remains to be elucidated. Methods Epigenetic evaluation was performed in 115 AF patients who underwent radiofrequency catheter ablation (RFCA) in a single institution. We measured methylation at approximately 850,000 bp cytosine-phosphate-guanine (CpG) sites in the 115 samples. Results The degree of methylation was compared across seven classification criteria: type of AF, late recurrence, impaired left atrium (LA) function, late gadolinium enhancement, LA diameter, LA volume, and flow velocity of the LA appendage. The four most significantly methylated genes in our cohort were DEFB104B, C3, TANC1, and TMEM9B. The DEFB104B gene (cg20223677 in the transcription start site), which encodes β-defensin 104B, was hypomethylated in three groups: those with late recurrence, impaired LA function, and impaired LAA flow velocity. Enriched functional annotation of the differentially methylated datasets revealed that five out of the seven AF groups in this cohort were associated with genes involved in the cell movement of endothelial cell lines, sprouting angiogenesis by endothelial cell lines, or migration of endothelial cell lines. Conclusion In this study, epigenetic profiling revealed that epigenetic modification might affect crucial traits of AF, such as the degree of atrial myopathy and treatment effects after RFCA, suggesting the hypothesis that the pathogenesis of AF might be affected by not only genetic variation or modifiable factors but also by epigenetic modulation. The identified methylation-susceptible loci can be used in targeting for epigenetic-based therapeutic agents.

Предиктори утримання синусового ритму в пацієнтів із пізньою персистентною фібриляцією передсердь після електричної кардіоверсії під час 6-місячного проспективного спостереження

The aim – to study the predictors of sinus rhythm (SR) maintenance in patients with persistent atrial fibrillation (AF) and duration of AF episode ≥90 days at 6-months follow-up after elective direct current (DC) cardioversion.Materials and methods. The cohort single-center study analyzed clinical and instrumental data from 59 persistent AF patients with duration of its episode ≥90 days (up to 12 months), who underwent an elective DC cardioversion. At 6-months follow-up, patients were subdivided into the groups depending on SR maintenance: 32 (54 %) patients with a maintained SR (G1), and 27 (46 %) patients with a failure to maintain SR (G2).Results. G2, as compared to G1, demonstrated more advanced heart failure (stage C occurred in 74 % and 44 %, respectively [p=0,019]). According to transthoracic echocardiography (TTE) data, G1, as opposed to G2, was characterized by better baseline structure parameters of left heart chambers, particularly the diameter of left atrium (LA), end-diastolic and end-systolic volumes left ventricular (LV) volumes, higher LV systolic function (by LV ejection fraction [EF]), and the majority of the cases without or with mild pulmonary hypertension (PH). Transesophageal echocardiography data suggested the cases of LA spontaneous (echo) contrast and LA appendage flow velocity (LAAFV) ≤ 40 cm/s to be more frequent in G2, in contrast to G1. We revealed the following predictors of SR maintenance after DC cardioversion at 6-months follow-up: higher LV EF (OR 1,07 (95 % CI 1,01–1,13); р=0,021); LAAFV &gt; 40 cm/s (OR 4,33 (95 % CI 1,06–17,78); р=0,042), and less advanced PH (OR 0,24 (95 % CI 0,06–0,93); р=0,038). TTE data from G1 at 6-months follow-up after DC cardioversion suggested the reverse remodeling of both atria (the decrease of LA diameter, LA and right atrium volumes and their indexes). Additionally, G2 demonstrated a worsening in LV systolic function (the rise of LV end-systolic volume and decrease of LV EF), as opposed to G1. Moreover, at 6-months follow-up, G2 patients presented with more advanced severity of PH, as well as mitral and tricuspid regurgitation, in contrast to G1.Conclusions. Better LV systolic function, LAAFV &gt; 40 cm/s and less advanced PH were the predictors of SR maintenance in patients with persistent AF and duration of its episode ≥ 90 days at 6-months follow-up after elective DC cardioversion. The SR maintenance at 6-months follow-up associated with the reverse remodeling of let heart chambers and right atrium. On the contrary, a failure to maintain SR associated with the decrease of LV systolic function, and more advanced PH, mitral and tricuspid regurgitation.

Assessment of left atrial appendage flow velocities to unmask atrial fibrillation in cryptogenic stroke

Abstract Funding Acknowledgements Type of funding sources: None. Background Hemostasis in the left atrial (LA) appendage (LAA) is a common cause of stroke, particularly in atrial fibrillation (AF). LAA flow have been determined to quantify LAA function. Objectives To investigate whether LAA peak flow velocities early after cryptogenic stroke have a predictive value for AF occurrence and to determine the determinants of impaired flow. Methods Consecutive cryptogenic stroke patients (139) were enrolled. LAA flow velocities during sinus rhythm were assessed early post-stroke with transesophageal echocardiography. All patients received rhythm monitoring using 7-day Holter and if negative, an implantable cardiac monitor. Results 47 Patients (34%) developed AF during a median follow-up of 554 days, median time to AF diagnosis was 93 days. Both, LAA filling (LAAfv) and emptying (LAAev) velocities were lower in stroke patients who developed AF (resp. 44.3±14.2 cm/s and 50.7±13.3 cm/s) compared with those who didn’t (resp. 59.8±14.0 cm/s and 76.8±17.3 cm/s). LAAev was the strongest predictor of AF with an AUC of 0.878 in ROC curve analysis and with optimal cut-off value of 55 cm/s. Age and mitral regurgitation were independent determinants of reduced LAAev. Conclusions Reduced LAA flow velocities can identify cryptogenic stroke patients at high risk of occult AF, and who may benefit from intensive rhythm monitoring or anticoagulation strategies.

Effect of percutaneous closure on atrium and appendage functions in patients with secundum atrial septal defects.

The study aimed to assess the impact of percutaneous transcatheter atrial septal defect (ASD) closure on atrium and atrial appandage functions among patients with ostium secundum ASDs. A total of 101 patients (34,7% male, 65,3% female, 37,6 ± 12) with the diagnosis of ostium secundum type ASD underwent transthorasic (TTE) and transesophageal echocardiography (TEE) before and six months after percutaneous transcatheter ASD closure. Pulmonary venous flow and atrial appendage flow velocities were obtained from the TEE recordings. The offline evaluation of the global and segmental atrial appendage strains were evaluated with speckle tracking echocardiography (STE) via EchoPac 6,3 (GE Vingmed, Horten, Norway). Mean values of pulmonary artery pressure, right ventricular, left atrium, left ventricular end-diastolic and end-systolic diameters were significantly decreased 6 months after ASD closure. Statistically significant changes were documented in pulmonary venous and left atrial appendage flow velocities after ASD closure. Both left and right atrial appendage flow velocities and global strains of atrial appandages were improved after ASD closure. The mean left atrial appendage global strain value was - 11.45 ± 4.13% before the procedure, this value was - 16.82 ± 3.78% sixth months after the procedure (P < 0.001).The mean right atrial appendage global strain was - 13.31 ± 4.84% before the procedure and - 18.53 ± 4.69% sixth months after the procedure (P < 0.001). Left and right atrial appendage flow velocities and global strains of left and right atrial appandage can be improved after transcatheter ASD closure. Percutaneous transcatheter closure of ASDs not only improves atrial and left ventricular dimensions but also have a positive impact on left and right atrial appandage functions.

Prediction of spontaneous echocardiographic contrast within the left atrial appendage in cardiac computed tomography of patients with atrial fibrillation.

This study aimed to assess the predictors of spontaneous echocardiographic contrast (SEC) using left atrial appendage (LAA) findings in cardiac computed tomography (CT) of patients with atrial fibrillation (AF). We retrospectively analyzed cardiac CT findings of the LAA, including morphology, volume, and filling defects, of 641 patients who underwent transesophageal echocardiography (TEE) prior to pulmonary vein isolation (PVI) from January 6, 2013 through December 16, 2019 at our institution. We investigated potential associated factors that might be predictors of SEC using cardiac CT findings and computed a receiver operator characteristic, choosing a threshold value at which the likelihood of SEC could be predicted based on the LAA volume indexed for body size. SEC correlated significantly with indexed LAA volume (P < 0.001; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.17-1.48) of 7.75 cm3/m2 or greater (sensitivity, 76.0%; specificity, 57.7%), LAA early filling defect (P = 0.005; OR, 2.72; 95% CI, 1.35-5.48), a history of persistent AF (P < 0.001; OR, 3.81; 95% CI, 1.86-7.80), and LAA flow velocity (P < 0.001; OR, 0.97; 95% CI, 0.96-0.99). Findings of LAA in cardiac CT can allow for the noninvasive estimation of SEC to determine the need for additional TEE investigation and the need to obtain additional information for risk stratification and management of thromboembolic events in patients with AF.

Assessment of left atrial appendage function by echocardiography.

The left atrial appendage (LAA) is considered not only to be the most frequent site of thrombus formation, but also to play a pivotal role in maintaining normal cardiac function. Transesophageal echocardiography (TEE) is widely used to assess LAA function. TheLAA flow velocityhasbeen used as a surrogate for LAA function, and it varies with multiple interrelated factors including age, hemodynamics, type of arrhythmia, and antiarrhythmic interventions. Relatively great importance ofLAA function is involved with intraatrial thrombus formation and subsequent thromboembolism, and thus, understanding of characteristics and behaviors of the LAA under various clinical conditions may help determine strategies against atrial thrombosis. Also, techniques other than TEE-derived Doppler to assess LAA function, such as tissue Doppler imaging, have been proposed. In this review, we introduce clinical and echocardiographic correlates of LAA function, the LAA flow velocity in particular, its significance, and how to interpret functional patterns of the LAA each relevant to specific clinical settings.

Abstract 31: The ATTICUS Randomized Controlled Trial - Subgroup Analyses

Background: ATTICUS is the third prospective randomized controlled trial that compared a direct oral anticoagulant (DOAC) vs. acetylsalicylic acid (ASA) for secondary prevention after embolic stroke of undetermined source (ESUS). Aim of ATTICUS was to determine whether apixaban, initiated within 28 days after ESUS, is superior to ASA in preventing new ischemic lesions on 12-month follow- up MRI (primary endpoint) in subjects with remote atrial fibrillation (AF) monitoring. Methods: Multicenter (14 German centers) open-label randomized (1:1) controlled trial with blinded endpoint assessment. ESUS patients with at least one risk factor for AF/cardiac thromboembolism (i.e., left atrium (LA) size &gt; 45 mm, spontaneous echo contrast in LA appendage, LA appendage flow velocity ≤ 0.2 m/s, atrial high-rate episodes, CHA2DS2-VASc ≥ 4, patent foramen ovale (PFO)) were enrolled. Study drug was initiated 3 to 28 days after minor/moderate stroke and ≥ 14 to 28 days after major stroke. ClinicalTrials.gov: NCT02427126. Funding by Bristol Meyers Squibb-Pfizer Alliance (Euro 2.2 Mio.) and Medtronic. Results: 352 patients were available for final analysis. New ischemic lesion(s) were found in 13.6% vs. 16.0% of patients in the apixaban and the ASA arm, respectively (p=0.57), intention-to-treat. AF was detected in 25.6 % of patients. No difference between study arms was found for other thromboembolism, death, SAE, major and clinically relevant bleeds. Conclusions: ATTICUS was the first trial testing the concept of DOAC vs. ASA in an enriched ESUS population. Mandatory cardiac monitoring, vessel imaging, and MRI in all ATTICUS patients will help to better understand this complex condition. We will present secondary analyses including on-treatment analysis, prevention of embolic/disabling lesions/strokes, association of stroke pattern with AF occurrence/macroangiopathic changes.

The risk factors of thrombus formation and the effect of catheter ablation on repetitive thrombus formation in patients with atrial fibrillation: a single center retrospective study in China

BackgroundAtrial fibrillation (AF) predisposes patients to the formation of atrial thrombi. The CHA2DS2-VASc score does not include all risk factors for atrial thrombosis. The present study is designed to explore the influencing factors of thrombus formation in patients with AF and to investigate the effect of catheter ablation (CA) on recurrent thrombosis in patients with a history of intracardiac thrombus.Methods(1) This study consisted of 1726 patients that underwent CA, among which 58 patients had a history of intracardiac thrombus prior to CA. The risk factors for thrombus formation were explored by comparing the baseline clinical characteristics of patients with and without atrial thrombus. (2) The left atrial appendage flow velocity (LAAFV) in patients with a history of intracardiac thrombus who were willing to undergo transesophageal echocardiography (TEE) at the latest follow-up were examined, and comparisons of the LAAFV was made before and after CA.ResultsThe median follow-up period is 13 months. Persistent AF was found to be the only independent risk factor affecting the formation of atrial thrombus among the investigated factors (OR 3.152; 95%CI 1.806–5.500; p < 0.001). Twenty-seven patients agreed to undergo TEE during follow-up, no clinical ischemic stroke events were recorded, no recurrent intracardiac thrombus formation was detected in patients, 15 patients maintained sinus rhythm (55.6%) during follow-up; successful CA significantly increased LAAFV (difference between latest evaluation prior to CA 17.46 ± 14.81 cm/s, p < 0.001).ConclusionsPersistent AF is the only independent risk factor for thrombus formation. Successful CA may improve the LAAFV and thereby decrease the risk of intracardiac thrombus formation.

Left atrial appendage thrombus formation, potential of resolution and association with prognosis in a large real-world cohort

Comprehensive data on factors influencing left atrial appendage (LAA) thrombus formation, resolution and impact on survival are limited. In this single-center, retrospective study 7759 (2010–2015) patients with symptomatic ongoing atrial fibrillation (AF) on admission were screened for LAA thrombi. 450 patients had LAA thrombi. 481 patients without LAA thrombi were randomly selected as controls. We assessed clinical, echocardiographic, laboratory parameters and long-term survival of both groups. Patients with LAA thrombi compared to controls were older, had more strokes, higher CHA2DS2 -VASc scores, worse renal function, less controlled diabetes, advanced heart failure, lower LAA emptying velocities, higher levels of cardiac and inflammatory markers (all p < 0.001). 56.3% of followed-up patients (304) dissolved their LAA thrombi. Chances of thrombus resolution increased with rising LAA flow velocities (OR 1.061, p = 0.022), whereas advanced age (OR 0.950, p < 0.001) and presence of permanent AF (OR 0.354, p < 0.001) decreased chances of thrombus resolution. Presence of LAA thrombi was associated with a markedly reduced 10-year survival probability (31% versus 69%). LAA thrombus formation is promoted by advanced structural heart disease, inflammation, diabetes and impaired renal function. Younger age, non-permanent AF and higher LAA flow velocities were predictors of thrombus resolution. Thrombus formation was associated with poor prognosis.

Left atrial appendage morphology with the progression of atrial fibrillation.

Left atrial appendage (LAA) size is crucial for determining the indication of transcatheter LAA closure. The aim of this study was to evaluate the differences in LAA morphology according to the types of atrial fibrillation (AF). A total of 299 patients (mean age: 67 ± 13 years) who underwent transesophageal echocardiography (TEE) were included. Patients were classified into non-AF (n = 64), paroxysmal AF (n = 86), persistent AF (n = 87), or long-standing persistent AF (n = 62). LAA morphology, including LAA ostial diameter and depth, was assessed using TEE. Patients with long-standing persistent AF had larger LAA ostial diameter and depth and lower LAA flow velocity. The maximum LAA ostial diameter was 19 ± 4 mm in patients with non-AF, 21 ± 4 mm in patients with paroxysmal AF, 23 ± 5 mm in patients with persistent AF, and 26 ± 5 mm in patients with long-standing persistent AF. LAA ostial diameter was increased by 2 or 3 mm with the progression of AF. LAA ostial diameter was correlated with LA volume index (R = 0.37, P < 0.01) and the duration of continuous AF (R = 0.30, P < 0.01), but not with age or the period from the onset of AF. In conclusion, LAA size was increased with the progression of AF.

Isoproterenol loading transesophageal echocardiography in atrial fibrillation.

In patients with sludge or severe spontaneous echo contrast (SEC) in the left atrial appendage (LAA), cases with isoproterenol loading transesophageal echocardiography (ISP-TEE) have been reported to identify the presence of thrombus in the LAA. This study aimed to assess the validity and hemodynamic changes of ISP-TEE in the LAA. We prospectively enrolled patients with atrial fibrillation (AF) who underwent ISP-TEE. The degree of sludge/SEC was categorized as being either absent (grade 0), mild SEC (grade 1), moderate SEC (grade 2), severe SEC or sludge (grade 3). The hemodynamic evaluation was performed by measuring LAA flow velocity, LAA tissue Doppler imaging (LAA-TDI) velocity, and pulmonary vein systolic forward flow velocity (PVS). In total, 35 patients (mean age 71 ± 7years; 71% male) underwent ISP-TEE. Among 35 patients, 30 patients had grade 3 or 2 SEC, 5 patients had grade 1 SEC. After ISP loading, 23 patients (66% of all patients) showed improved sludge/SEC and one patient was diagnosed with thrombus in the LAA. There were 25 patients with grade 1 SEC, or no SEC (classified as Group1), 10 patients had residual sludge or grade 2 to 3 SEC (classified as Group2) after ISP administration. LAA flow, LAA-TDI, and PVS velocities were significantly higher in group 1 than in group 2 after ISP administration. There was no complication during the examination and after 24h and 3months. ISP infusion may be a potential tool to recognize LAA thrombus under the sludge/SEC during TEE in AF.