Atrial Appendage In Patients Research Articles

Evaluation of the volume and function of left atrial appendage and left atrium in patients with atrial fibrillation by three-dimensional transesophageal echocardiography and transthoracic echocardiography

To evaluate the volume and function of left atrium and left atrial appendage in patients with atrial fibrillation by three-dimensional transesophageal echocardiography and transthoracic echocardiography. Methods: A total of 112 patients with atrial fibrillation were divided into two groups: a paroxysmal atrial fibrillation (ParAF) group (n=80) and a persistent atrial fibrillation (PerAF) group (n=32). Control group was people without atrial fibrillation (n=40). Clinical data of the participants were collected. Left atrial dimension (LAD), left atrial volume (LAV), left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) were measured by transthoracic echocardiography, while left atrial appendage peak emptying flow velocity (LAAeV), left atrial appendage peak filling flow velocity (LAAfV), left atrial appendage maximum volume (LAAVmax) and left atrial appendage minimum volume (LAAVmin) were measured by three-dimensional transesophageal echocardiography. Left atrial volume index (LAVI), left ventricular ejection fraction (LVEF) and left atrial appendage ejection fraction (LAAEF) were calculated. Results: Compared with the control group, LAAEF, LAAeV and LAAfV in the ParAF group were decreased obviously, while LAD, LAV, LAVI, LAAVmax and LAAVmin in the ParAF group were increased obviously (P<0.05). Compared with the ParAF group, LAAEF, LAAeV and LAAfV in the PerAF group were also decreased obviously, and LAD, LAV, LAVI, LAAVmax and LAAVmin in the ParAF group were also increased obviously (P<0.05). There was no statistically significant difference in LVEDV, LVESV, LVEF between the ParAF group and the PerAF group (P<0.05). Conclusion: Left atrium and left atrial appendage were enlarged and the function of left atrial appendage was declined in patients with AF, and the changes were more obvious in patients with PerAF compared with patients with ParAF by three-dimensional transesophageal echocardiography and transthoracic echocardiography.

A1742 Expression of Rho Kinase and its mechanism in the left atrial appendage in patients with atrial fibrillation

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The cessation of oral anticoagulation following left atrial appendage surgery.

Atrial fibrillation is associated with a significantly increased risk of stroke, and oral anticoagulation is the mainstay of preventative treatment. Scenarios arise where the risks of treatment with oral anticoagulation may outweigh the benefits, most commonly when there is an elevated risk of bleeding. Studies of percutaneous closure of the left atrial appendage have strongly implicated this structure in the etiology of stroke in atrial fibrillation, and provide some rationale for the discontinuation of oral anticoagulation following percutaneous closure device implantation. A common clinical concern is the safety of cessation of oral anticoagulation after surgical closure of the left atrial appendage in patients with a history of atrial fibrillation. Here, we review the evidence guiding this management decision and draw comparison with data on percutaneous closure.

P3843Closure of left atrial appendage in patients with atrial fibrillation undergoing first-time coronary bypass graft surgery is associated with lower risk of stroke

P3843Closure of left atrial appendage in patients with atrial fibrillation undergoing first-time coronary bypass graft surgery is associated with lower risk of stroke

Хирургическая изоляция ушка левого предсердия у пациентов с фибрилляцией предсердий: анализ проблемы

Хирургическая изоляция ушка левого предсердия у пациентов с фибрилляцией предсердий: анализ проблемы

Inhibition of renin-angiotensin axis reduces the risk of thrombus formation in the left atrial appendage in patients with hypertension complicated by atrial fibrillation.

Aims:We examined whether the use of a renin-angiotensin-aldosterone system (RAS) inhibitor plays a role in protecting against left atrial appendage thrombus (LAAT) in patients with hypertension complicated by atrial fibrillation (AF).Methods:Two observational studies were conducted on patients with diagnoses of hypertension and AF, who were categorized into RAS inhibitor user or nonuser groups. Demographic characteristics, clinical characteristics, echocardiographic parameters and hemostatic markers were examined and the occurrence of LAAT during follow-up were recorded.Results:In the first study (n = 131), LA peak systolic strain and LAA emptying flow velocity (LAA eV) were significantly increased in patients on RAS inhibitors compared with the nonuser group (p < 0.05). Lower D-dimer and fibrinogen levels were observed in patients on RAS inhibitors (p < 0.05). In the second study (n = 99), 25.9% (n = 11) of patients on RAS inhibitors developed LAAT, compared with 46.7% (n = 21) in the nonuser group (p < 0.05). After controlling for risk factors related to LAAT, use of RAS inhibitors remained associated with a significantly lower risk of developing LAAT (HR, 0.406; 95% CI, 0.191–0.862; p = 0.019).Conclusions:RAS inhibitors use was associated with a significant reduction in the risk of LAAT in patients with hypertension and AF.

Thrombin induces protease-activated receptor 1 signaling and activation of human atrial fibroblasts and dabigatran prevents these effects

BackgroundData with animal cells and models suggest that thrombin activates cardiac fibroblasts (Fib) to myofibroblasts (myoFib) via protease-activated receptor 1 (PAR1) cleavage, and in this way promotes adverse atrial remodeling and, thereby, atrial fibrillation (AF). ObjectiveHere, we explored the effects of thrombin on human atrial Fib and whether they are antagonized by the clinically available direct thrombin inhibitor, dabigatran. MethodsFib isolated from atrial appendages of patients without AF undergoing elective cardiac surgery were evaluated for PAR expression and treated with thrombin with or without dabigatran. PAR1 cleavage, downstream signaling and myoFib markers were investigated by immunofluorescence and Western blot. Collagen synthesis, activity of matrix metalloprotease (MMP)-2 and proliferation were assessed by Picro-Sirius red staining, gelatinolytic zymography and BrdU incorporation, respectively. Fib function was studied as capability to contract a collagen gel and stimulate the chemotaxis of peripheral blood monocytes from healthy volunteers. ResultsPrimary human atrial Fib expressed PAR1, while levels of the other PARs were very low. Thrombin triggered PAR1 cleavage and phosphorylation of ERK1/2, p38 and Akt, elicited a switch to myoFib enriched for αSMA, fibronectin and type I collagen, and induced paracrine/autocrine transforming growth factor beta-1, cyclooxygenase-2, endothelin-1 and chemokine (C-C motif) ligand 2 (CCL2); conversely, MMP-2 activity decreased. Thrombin-primed cells displayed enhanced proliferation, formed discrete collagen-containing cellular nodules, and stimulated the contraction of a collagen gel. Furthermore, their conditioned medium caused monocytes to migrate. All these effects were prevented by dabigatran. ConclusionThese results with human cells complete the knowledge about thrombin actions on cardiac Fib and strengthen the translational potential of the emerging paradigm that pharmacological blockade of thrombin may counteract molecular and cellular events underlying AF.

OP-477 - The Relationship between Cardiovascular Risk Factors and Remodelling Pattern in Left Atrium and Atrial Appendage in Patients with Sinus Rhythm

OP-477 - The Relationship between Cardiovascular Risk Factors and Remodelling Pattern in Left Atrium and Atrial Appendage in Patients with Sinus Rhythm

Expression of Rho Kinase and Its Mechanism in the Left Atrial Appendage in Patients with Atrial Fibrillation.

To study the expression of Rho kinase (Rho associated coil forming protein kinase-1, ROCK-1) and its substrate myosin phosphatase target subunit 1 (myosin phosphatase target subunit-1, MYPT-1), connexin 40 (Cx40) and connexin 43 (Cx43) in the left atrial appendage of patients with atrial fibrillation, and explore the role of ROCK signaling pathway in patients with atrial fibrillation and its underlying mechanism.Methods: 40 patients undergoing open heart surgery were divided into two groups; atrial fibrillation group (AF group) and sinus rhythm group (SR group). About 100 mg of left atrial appendage tissue was taken during surgery and quickly frozen in liquid nitrogen. Immunohistochemistry and western blot were performed to evaluate the expression and location of ROCK-1, MYPT-1, Cx40 and Cx43 in the left atrial appendage tissue.Results: The results indicated that the expression of ROCK-1, MYPT-1, and Cx40 in the left atrial appendage in patients with atrial fibrillation was significantly upregulated (P < .01), the difference in the two groups was statistically significant, and ROCK-1, Cx40, and MYPT-1 expression in the AF group were higher than those in sinus rhythm group; there was a weakly positive expression of Cx43 protein in the AF group and sinus rhythm group, the difference was not statistically significant, and ROCK-1 and MYPT-1 expression showed a significant positive correlation (r = 0.968, P < .05), MYPT 1 and Cx40 protein expression was also positively correlated (r = 0.983, P < .05). Evidence in the left atrial appendage tissue of patients with atrial fibrillation showed that some proteins in Rho/ROCK pathway were upregulated, and MYPT-1 and Cx40 protein expression in AF group were significantly higher than that of SR group, which was also positively correlated; Cx43 showed a weak positive expression in both the SR group and AF group, which indicates that Rho kinase may induce expression of Cx40 by phosphorylation of MYPT-1; Cx43 may not be involved, suggesting that Rho kinase signaling pathway may activate and play an important role in the pathogenesis of atrial fibrillation lesions.

3D-computed tomography to compare the dimensions of the left atrial appendage in patients with normal sinus rhythm and those with paroxysmal atrial fibrillation.

Although paroxysmal atrial fibrillation (PAF) is an important cause of cardioembolic stroke, in contrast to chronic AF patients, the anatomical features of the left atrial appendage (LAA) in PAF patients remain unknown. Here, we investigated differences in LAA structures in patients with PAF and those with normal sinus rhythms (NSR) using 3D-computed tomography (3D-CT), which allows us to visualize complicated LAA structures at high spatial resolution. Study subjects were 30 consecutive PAF and 30 NSR patients with complete enhanced cardiac 3D-CT images available. After reconstruction of 3D LAA images, anatomical parameters of the LAA were measured and compared according to three proposed definitions of the LAA orifice plane determined by the following anatomical landmarks: DEF#1, center of warfarin ridge and centerline of proximal left circumflex artery; DEF#2, slope of warfarin ridge and mitral valve annulus; DEF#3, observers' discretion by progressive rotation using the observers' best estimate without the use of landmarks. The LAA volumes of the PAF groups were significantly greater than the NSR group according to all 3 definitions (DEF#1: 1.43 times, DEF#2: 1.44 times, and DEF#3: 1.36 times greater). The LAA orifice area was significantly larger in PAF than in NSR according to DEF#2, but was similar by DEF#1 and DEF#3. Intra-observer and inter-observer variations for any LAA measurements were very low. In conclusion, 3D-CT-based quantitative assessment of the LAA provides highly reproducible and detailed measurements, which can successfully discriminate differences of LAA volume between patients with NSR and those with PAF, suggesting significantly greater volumes in the latter.

Expression of Follistatin-Like 3 is not Altered in the Right Atrial Appendage in Patients with Myocardial Infarction

Expression of Follistatin-Like 3 is not Altered in the Right Atrial Appendage in Patients with Myocardial Infarction

71Percutaneous suture closure of the left atrial appendage in patients with a high CHA2DS2 VASC score and absolute contraindication for oral anticoagu-lant therapy – the UNITED KINGDOM experience

71Percutaneous suture closure of the left atrial appendage in patients with a high CHA2DS2 VASC score and absolute contraindication for oral anticoagu-lant therapy – the UNITED KINGDOM experience

Age-related changes in morphology of left atrial appendage in patients with atrial fibrillation.

The purpose of this study was to evaluate the relationship between age and frequency of left atrial appendage (LAA) morphology in patients with atrial fibrillation (AF) compared with sinus rhythm (SR). We enrolled 145 AF patients, and 199 SR patients for the control group without any cardiovascular disease. LAA volume index (LAAVi) and morphology were assessed by electrocardiogram-gated computed tomography angiography. LAA morphology was classified into "chicken wing" or "non-chicken wing" according to the previously described classification. There was no significant trend in frequency of non-chicken wing morphology among ages in the SR group (p = 0.36 for trend), whereas the frequency was negatively related to age in the AF group (p = 0.002 for trend). In multivariable logistic regression, age > 65 (odds ratio [OR] 0.42, p = 0.002) and duration of AF (OR 0.53, p = 0.010) and LAAVi (OR 0.62, p = 0.017) were independent factors of non-chicken wing LAA morphology in the AF group. LAA morphology is affected by age, especially in patients with AF. When we utilize non-chicken wing LAA morphology as a stroke risk factor in patients with AF, we should pay attention to their age.

In-vitro examination of the positive inotropic effect of caffeine and taurine, the two most frequent active ingredients of energy drinks

BackgroundOur study aimed to evaluate changes in the contractile behavior of human myocardium after exposure to caffeine and taurine, the main active ingredients of energy drinks (EDs), and to evaluate whether taurine exhibits any inotropic effect at all in the dosages commonly used in EDs.MethodsMyocardial tissue was removed from the right atrial appendages of patients undergoing cardiac surgery and prepared to obtain specimens measuring 4 mm in length. A total of 92 specimens were exposed to electrical impulses at a frequency of 75 bpm for at least 40 min to elicit their maximum contractile force before measuring the isometric contractile force (ICF) and duration of contraction (CD). Following this, each specimen was treated with either taurine (group 1, n = 29), or caffeine (group 2, n = 31) or both (group 3, n = 32). After exposure, ICF and CD measuring were repeated. Post-treatment values were compared with pre-treatments values and indicated as percentages.ResultsExposure to taurine did not alter the contraction behavior of the specimens. Exposure to caffeine, in contrast, led to a significant increase in ICF (118 ± 03%, p < 0.01) und a marginal decrease in CD (95 ± 1.6%, p < 0.01). Exposure to a combination of caffeine and taurine also induced a statistically significant increase in ICF (124 ± 4%, p < 0.01) and a subtle reduction in CD (92 ± 1.4%, p < 0.01). The increase in ICF achieved by administration of caffeine was similar to that achieved by a combination of both caffeine and taurine (p = 0.2).The relative ICF levels achieved by administration of caffeine and a combination of taurine and caffeine, respectively, were both significantly higher (p < 0.01) than the ICF resulting from exposure to taurine only.ConclusionWhile caffeine altered the contraction behavior of the specimen significantly in our in-vitro model, taurine did not exhibit a significant effect. Adding taurine to caffeine did not significantly enhance or reduce the effect of caffeine.

MiR‑132 in atrial fibrillation directly targets connective tissue growth factor.

Atrial fibrillation (AF) is the most frequently occurring, persistent cardiac arrhythmia, and the hallmark of AF‑dependent structural remodeling is atrial fibrosis. Connective tissue growth factor (CTGF) is important in the process of fibrosis. The association between miRNA and CTGF in AF‑dependent fibrosis remains to be elucidated. The present study aimed to determine if microRNA (miR)‑132 was able to regulate CTGF with an anti‑fibrotic effect in AF. A total of ten dogs or patients were assigned to control (n=4) and AF groups (n=6). The left atrium of dogs or right atrial appendage of patients was observed. Following this, cardiac fibroblasts of adult rats were treated with or without angiotensin II (Ang II). Furthermore, cardiac fibroblasts were transfected with miR‑132 mimics, inhibitor or negative control. The expression of miR‑132 and CTGF were analyzed by reverse transcription‑quantitative polymerase chain reaction or western blotting. These analyses demonstrated that miR‑132 expression was decreased and CTGF increased in the human and canine models with AF. The expression of miR‑132 and CTGF protein levels were upregulated in AngII stimulated cardiac fibroblasts of adult rats. Furthermore, when miR‑132 was introduced into cardiac fibroblasts, the expression of miR‑132 increased significantly whereas the expression of CTGF decreased. Inverse results were observed when cardiac fibroblasts were transfected with miR‑132 inhibitor. The luciferase reporter assay was then performed to confirm that miR‑132 may suppress CTGF expression by binding to its 3'‑untranslated region. In conclusion, miR‑132 may target CTGF in regulating fibrosis in Ang II‑treated cardiac fibroblasts. These findings may aid in providing potential therapeutic targets in the treatment of AF.

Percutaneous closure of the left atrial appendage in patients with diabetes mellitus.

Left atrial appendage closure is a preventive treatment of atrial fibrillation-related thrombo-embolism. Patients with diabetes mellitus have increased risk for a negative outcome in percutaneous cardiac interventions. We assessed whether percutaneous left atrial appendage closure is safe and effective in patients with diabetes mellitus. We included 78 patients (mean age of 74.4 ± 8.3 years) with indication for left atrial appendage closure in an open-label observational single-centre study. Patients with diabetes mellitus ( n = 31) were at higher thrombo-embolic and bleeding risk (CHA2DS2-VASc: 4.5 ± 0.9, HAS-BLED: 4.7 ± 0.7) compared to patients without diabetes mellitus ( n = 47, CHA2DS2-VASc: 3.5 ± 1.0, HAS-BLED: 4.1 ± 0.8; p < 0.001 for both). Pre- and periprocedural risk was elevated in patients with diabetes mellitus (Euro II-Score: 6.6 ± 3.7 vs 3.9 ± 1.9, p < 0.01; Society of Thoracic Surgeons (STS)-Score: 4.0 ± 2.5 vs 2.6 ± 1.2, p < 0.01). Procedural success was similar. Periprocedural major adverse cardiac and cerebrovascular events occurred in one patient from the control group (2.1%), whereas patients with diabetes mellitus had no events ( p = 0.672). Follow-up of 6 months revealed no bleeding complication in both groups. No stroke occurred in follow-up, and left atrial appendage flow velocity reduction (55.6 ± 38.6 vs 51.4 ± 19.1 cm/s, p = 0.474) and rate of postinterventional leakage in the left atrial appendage were comparable (0% vs 2.1%, p = 0.672). Despite patients with diabetes mellitus are high-risk patients, the outcome of percutaneous left atrial appendage closure is similar to patients without diabetes mellitus.

1307Thorascopic ligation of the left atrial appendage in patients with atrial fibrillation who are at high risk of stroke using the atriclip ligation system

1307Thorascopic ligation of the left atrial appendage in patients with atrial fibrillation who are at high risk of stroke using the atriclip ligation system

Role of Sprouty1 (Spry1) in the pathogenesis of atrial fibrosis

Atrial fibrosis is the hallmark of atrial fibrillation (AF) dependent structure remodeling. Besides, sprouty 1 (Spry1) plays a key role in the process of fibrosis. In this study, we investigated whether Spry1 could regulate TGF-β1 in atrial fibrosis. Ten dogs or patients were assigned to control (n=4) and AF group (n=6). The left atrium of dogs or right atrial appendage of patients was taken. After that, cardiac fibroblasts were treated with or without angiotensin II (Ang II). Furthermore, cardiac fibroblasts were transfected with lentivirus of Spry1 over-expression vector, Spry1 shRNA or negative control (NC). And the protein expression of Spry1 and TGF-β1 was analyzed by western blot and immunohistochemistry. The results showed that TGF-β1 was highly expressed while Spry1 was lowly expressed in the models of human and canine with AF. Besides, the protein expression of TGF-β1 was up-regulated and Spry1 was down-regulated in Ang II stimulated cardiac fibroblasts. Furthermore, when Spry1 was knockdown in Ang II-induced cardiac fibroblasts, the cell proliferation and the TGF-β1 protein expression increased significantly, while Spry1 over-expression showed inverse results. Our results demonstrated that Spry1 may target TGF-β1 in regulating fibrosis. These findings may provide possible therapeutic targets in atrial fibrosis.

Left atrial appendage in rheumatic mitral valve disease: The main source of embolism in atrial fibrillation

To demonstrate that surgical removal of the left atrial appendage in patients with rheumatic mitral valve disease and long standing persistent atrial fibrillation decreases the possibility of stroke. This also removes the need for long-term oral anticoagulation after surgery. A descriptive, prospective, observational study was conducted on 27 adult patients with rheumatic mitral valve disease and long standing persistent atrial fibrillation, who had undergone mitral valve surgery and surgical removal of the left atrial appendage. Oral anticoagulation was stopped in the third month after surgery. The end-point was the absence of embolic stroke. An assessment was also made of postoperative embolism formation in the left atrium using transthoracic echocardiography. None of the patients showed embolic stroke after the third post-operative month. Only one patient exhibited transient ischaemic attack on warfarin therapy within the three postoperative months. Left atrial thrombi were also found in 11 (40.7%) cases during surgery. Of these, 6 (54.5%) had had embolic stroke, with no statistical significance (P=.703). This study suggests there might be signs that the left atrial appendage may be the main source of emboli in rheumatic mitral valve disease, and its resection could eliminate the risk of stroke in patients with rheumatic mitral valve disease and long-standing persistent atrial fibrillation.

Morphologic Assessment of the Left Atrial Appendage in Patients with Atrial Fibrillation by Gray Values–Inverted Volume-Rendered Imaging of Three-Dimensional Transesophageal Echocardiography: A Comparative Study with Computed Tomography

Accurate assessment of left atrial appendage (LAA) morphology is crucial in determining an LAA occlusion strategy. The aim of this study was to develop a novel echocardiographic volume-rendered imaging technique to visualize LAA morphology. This was a retrospective study. Forty patients with atrial fibrillation who underwent three-dimensional (3D) transesophageal echocardiography (TEE) and cardiac computed tomographic angiography (CCTA) before catheter ablation were enrolled. Full-volume 3D data were acquired and displayed in gray values-inverted (GVI) mode. Threshold segmentation and interactive segmentation were used to create 3D digital replicas of the LAA chambers. The morphologic classification, number of lobes, and dimensions of the LAA were analyzed and compared with the data obtained with CCTA. LAA morphology and measurements were successfully acquired via CCTA and 3D GVI TEE in all 40cases. In terms of LAA morphologic classifications, 19 cases of chicken wing, eight of windsock, nine of cauliflower, and four of cactus morphology were determined using 3D GVI TEE, and 20 cases of chicken wing, eight of windsock, eight of cauliflower, and four of cactus morphology were determined using CCTA. The κ value between these two methods was 0.963. Measurements of maximal diameter, minimal diameter, and area of the ostia and the depth of the LAAs were larger when based on the 3D GVI transesophageal echocardiographic data than when using cardiac computed tomographic angiographic data (P<.01); however, there was agreement between the results. Formed thrombi were well displayed by both computed tomography and 3DGVI TEE. Three-dimensional GVI TEE can be used to acquire LAA morphologic volume-rendered images that are similar to computed tomographic volume-rendered images, and it shows promise as a feasible and valuable modality for planning individual LAA occlusion procedures.