Hemodynamic Changes in the Left Atrium due to Atrial Fibrillation

2011 ◽  
Author(s):  
Kenichi Funamoto ◽  
Ryo Koizumi ◽  
Toshiyuki Hayase ◽  
Muneichi Shibata ◽  
Tomoyuki Yambe
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
High Frequency ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Pulmonary Veins ◽  
Hemodynamic Changes ◽  
Structure Interaction ◽  
Interaction Simulation

The left atrium (LA), which connects four pulmonary veins (PVs) to the left ventricle (LV), has a characteristic shape called the left atrial appendage (LAA) under the left PV. Atrial fibrillation (AF) is a heart disease, by which irregular electrical signals with high-frequency contraction (> 400 bpm) occur in the LA. Although AF itself is not fatal, it may cause thrombus formation, resulting to cerebral infarction. In this study, hemodynamics in the LA with/without AF was investigated by means of fluid-structure interaction simulation.

scholarly journals Fluid–structure interaction in a fully coupled three-dimensional mitral–atrium–pulmonary model

2021 ◽  
Author(s):  
Liuyang Feng ◽  
Hao Gao ◽  
Nan Qi ◽  
Mark Danton ◽  
Nicholas A. Hill ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Pulmonary Veins ◽  
Three Dimensional ◽  
Left Heart ◽  
Structure Interaction ◽  
Acute Mitral Regurgitation ◽  
Reversal Flow

AbstractThis paper aims to investigate detailed mechanical interactions between the pulmonary haemodynamics and left heart function in pathophysiological situations (e.g. atrial fibrillation and acute mitral regurgitation). This is achieved by developing a complex computational framework for a coupled pulmonary circulation, left atrium and mitral valve model. The left atrium and mitral valve are modelled with physiologically realistic three-dimensional geometries, fibre-reinforced hyperelastic materials and fluid–structure interaction, and the pulmonary vessels are modelled as one-dimensional network ended with structured trees, with specified vessel geometries and wall material properties. This new coupled model reveals some interesting results which could be of diagnostic values. For example, the wave propagation through the pulmonary vasculature can lead to different arrival times for the second systolic flow wave (S2 wave) among the pulmonary veins, forming vortex rings inside the left atrium. In the case of acute mitral regurgitation, the left atrium experiences an increased energy dissipation and pressure elevation. The pulmonary veins can experience increased wave intensities, reversal flow during systole and increased early-diastolic flow wave (D wave), which in turn causes an additional flow wave across the mitral valve (L wave), as well as a reversal flow at the left atrial appendage orifice. In the case of atrial fibrillation, we show that the loss of active contraction is associated with a slower flow inside the left atrial appendage and disappearances of the late-diastole atrial reversal wave (AR wave) and the first systolic wave (S1 wave) in pulmonary veins. The haemodynamic changes along the pulmonary vessel trees on different scales from microscopic vessels to the main pulmonary artery can all be captured in this model. The work promises a potential in quantifying disease progression and medical treatments of various pulmonary diseases such as the pulmonary hypertension due to a left heart dysfunction.

scholarly journals Effect of the Alterations in Contractility and Morphology Produced by Atrial Fibrillation on the Thrombosis Potential of the Left Atrial Appendage

2021 ◽  
Vol 9 ◽  
Author(s):  
Danila Vella ◽  
Alessandra Monteleone ◽  
Giulio Musotto ◽  
Giorgia Maria Bosi ◽  
Gaetano Burriesci
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Fluid Dynamic ◽  
Atrial Appendage ◽  
Primary Role ◽  
Shear Strain Rate ◽  
Increased Risk

Atrial fibrillation (AF) is a common arrhythmia mainly affecting the elderly population, which can lead to serious complications such as stroke, ischaemic attack and vascular dementia. These problems are caused by thrombi which mostly originate in the left atrial appendage (LAA), a small muscular sac protruding from left atrium. The abnormal heart rhythm associated with AF results in alterations in the heart muscle contractions and in some reshaping of the cardiac chambers. This study aims to verify if and how these physiological changes can establish hemodynamic conditions in the LAA promoting thrombus formation, by means of computational fluid dynamic (CFD) analyses. In particular, sinus and fibrillation contractility was replicated by applying wall velocity/motion to models based on healthy and dilated idealized shapes of the left atrium with a common LAA morphology. The models were analyzed and compared in terms of shear strain rate (SSR) and vorticity, which are hemodynamic parameters directly associated with thrombogenicity. The study clearly indicates that the alterations in contractility and morphology associated with AF pathologies play a primary role in establishing hemodynamic conditions which promote higher incidence of ischaemic events, consistently with the clinical evidence. In particular, in the analyzed models, the impairment in contractility determined a decrease in SSR of about 50%, whilst the chamber pathological dilatation contributed to a 30% reduction, indicating increased risk of clot formation. The equivalent rigid wall model was characterized by SSR values about one order of magnitude smaller than in the contractile models, and substantially different vortical behavior, suggesting that analyses based on rigid chambers, although common in the literature, are inadequate to provide realistic results on the LAA hemodynamics.

scholarly journals Anatomical Characteristics of the Left Atrium and Left Atrial Appendage in Relation to the Risk of Stroke in Patients with Versus without Atrial Fibrillation

2021 ◽  
Author(s):  
Jeff M. Smit ◽  
Judit Simon ◽  
Mohammed El Mahdiui ◽  
Lili Száraz ◽  
Philippe J. van Rosendael ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Suspected Coronary Artery Disease ◽  
Atrial Appendage ◽  
Volumetric Assessment ◽  
Study Population ◽  
Prior Stroke

Background - The left atrial appendage (LAA) has been regarded as an important source of cardiac thrombus formation and appears important in the contribution to thrombo-embolism in patients with atrial fibrillation (AF). Our aim was to evaluate the relationship between LAA morphology and previous stroke and/or transient ischemic attack (TIA) in two large and distinct patient cohorts with and without known AF. Methods - The study population consisted of patients with and without drug-refractory AF who underwent computed tomography (CT) prior to transcatheter AF ablation, or clinically indicated for suspected coronary artery disease (CAD). The CT data were used for volumetric assessment of the left atrium (LA) and LAA and to determine LAA morphology. The LAA was classified by 3 readers in consensus as chicken wing, swan, cauliflower or windsock, based on predefined morphology classification criteria. Results - In total, 1813 patients (mean age 59 ± 11 years, 42% female) who underwent CT were included in this analysis (908 patients with AF and 905 patients without known AF). Swan LAA morphology was independently associated with prior stroke/TIA in the overall study population (OR 3.40, P <0.001), and in patients with (OR 2.88, P = 0.012) and without known AF (OR 3.96, P = 0.011). Conclusions - Swan morphology of the LAA is independently associated with prior stroke and/or TIA in patients with known AF, as well as in patients not previously diagnosed with AF.

scholarly journals Short- and mid-term results of thoracoscopic atrial fibrillation ablation

2020 ◽  
Vol 8 (4S) ◽  
pp. 82-88
Author(s):  
E. A. Khomenko ◽  
S. E. Mamchur ◽  
K. A. Kozyrin ◽  
R. S. Tarasov ◽  
K. V. Bakovsky
Keyword(s):  
Atrial Fibrillation ◽  
Radiofrequency Ablation ◽  
Catheter Ablation ◽  
Sinus Rhythm ◽  
Left Atrium ◽  
Atrial Flutter ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Pulmonary Veins ◽  
One Year

Aim. Evaluation of short- and mid-term (up to one year) results of aт atrial fibrillation thoracoscopic radiofrequency ablation (TRFA) combined with left atrial appendage resection.Methods. 10 patients with persistent AF were included in the study. In 5 cases surgical ablation was performed as the primary intervention and in 5 cases surgery were preceded by two unsuccessful catheter procedures. Age of the patients was 54.4 (41; 63) years, duration of arrhythmic anamnesis – 5.6 (4.8; 6.8) years, anteroposterior size of the left atrium – 4.7 (45; 51 mm), LV ejection fraction – 63 (58; 68) %. TRFA included an isolation of right and left pulmonary veins, ablation lines along the roof and base of posterior wall of the left atrium, left atrial appendage resection.Results. In all cases of TRFA exit-block from the pulmonary veins was achieved. Among 10 procedures, a stable sinus rhythm was documented in 6 patients. In the remaining 4 patients AF was observed only in one case, and the other three demonstrated atypical atrial flutter, that given us a reason to repeat catheter procedures. In three cases of left atrial flutter, catheter ablation led to sinus rhythm restoration, and in case of AF and total sclerosis of left atrium a decision to refuse RF ablation was made. Complications were presented by a single case of bilateral phrenic nerve palsy, which required plication of the diaphragm, and two spontaneously resolved pulmonary atelectasis.Conclusion. The efficacy of atrial fibrillation thoracoscopic radiofrequency ablation during the follow-up period of one year was 90% regarding selective hybrid approach (thoracoscopic + catheter procedure). Procedure safety of TRFA was much lower than that of catheter ablation: the total number of small and big complications was 30%.

scholarly journals Large extracellular vesicles in the left atrial appendage in patients with atrial fibrillation—the missing link?

2021 ◽  
Author(s):  
Andreas Zietzer ◽  
Baravan Al-Kassou ◽  
Paul Jamme ◽  
Verena Rolfes ◽  
Eva Steffen ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Extracellular Vesicles ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Flow Cytometric Analysis ◽  
Heart Rhythm ◽  
Atrial Appendage ◽  
Peripheral Embolization

AbstractAtrial fibrillation (AF) is the most frequent arrhythmic disease in humans, which leads to thrombus formation in the left atrial appendage and stroke through peripheral embolization. Depending on their origin, large extracellular vesicles (lEVs) can exert pro-coagulant functions. In the present study, we investigated how different types of AF influence the levels of large EV subtypes in three distinct atrial localizations. Blood samples were collected from the right and left atrium and the left atrial appendage of 58 patients. 49% of the patients had permanent AF, 34% had non-permanent AF, and 17% had no history of AF. Flow cytometric analysis of the origin of the lEVs showed that the proportion of platelet-derived lEVs in the left atrial appendage was significantly higher in permanent AF patients compared to non-permanent AF. When we grouped patients according to their current heart rhythm, we also detected significantly higher levels of platelet-derived lEVs in the left atrial appendage (LAA) in patients with atrial fibrillation. In vitro studies revealed, that platelet activation with lipopolysaccharide (LPS) leads to higher levels of miR-222-3p and miR-223-3p in platelet-derived lEVs. Treatment with lEVs from LPS- or thrombin-activated platelets reduces the migration of endothelial cells in vitro. These results suggest that permanent atrial fibrillation is associated with increased levels of platelet-derived lEVs in the LAA, which are potentially involved in LAA thrombus formation.

P4731Procedure-related acute thrombosis after surgical left atrial appendage occlusion for atrial fibrillation

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Inoue ◽  
T Shimizu ◽  
A Yoshimoto ◽  
Y Suematsu
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Cardiac Ct ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Atrial Appendage ◽  
Full Cohort ◽  
Exact Test ◽  
Acute Thrombosis ◽  
Laa Closure

Abstract Background/Introduction Left atrial appendage (LAA) occlusion is an effective strategy for thromboembolism prevention in patients with atrial fibrillation (AF), and the novel methods of occlusion is various. The acute thrombosis after percutaneous LAA occlusion devices has been recently reported, but thrombus formation after surgical LAA occlusion is still unclear. Purpose This study aimed to analyse the incidence and prognosis of thrombus formation on closure stump line in patients with AF who underwent surgical LAA occlusion. Methods This study retrospectively analised the data from patients treated with two methods of surgical LAA closure, resection or clipping, from January 2014 to November 2018. Results A total of 187 consecutive patients with AF underwent surgical LAA closure (31 clipping and 156 stapler resection). 170 patients (91%) underwent cardiac CT for LAA imaging on postoperative day 2. The incidence of acute procedure-related thrombus formation in full cohort was 19% (35 cases). The incidence of acute thrombus in patients with clipping and resection was 19% and 16%, respectively (Fisher's exact test, p=0.8). All of 35 patients who had thrombus on LAA closure stump line underwent cardiac CT again 3 months after the primary CT. In all patients with secondary cardiac CT, thrombus on LAA closure stump line disappeared. No symptomatic thromboembolism occurred during the follow-up from operation to secondary CT scan. Conclusion(s) Thrombus formation on stump after surgical LAA closure may often occur on acute phase. The optimal LAA imaging and anti-coagulation therapy after surgical LAA occlusion will prevent patients with acute thrombus from thromboembolism.

P1415Wide antral circumferential pulmonary vein isolation ablation using a novel balloon cryoablation catheter

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
A P Martin ◽  
M Fowler ◽  
N Lever
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Pulmonary Vein ◽  
Pulmonary Vein Isolation ◽  
Paroxysmal Atrial Fibrillation ◽  
Left Atrial ◽  
Pulmonary Veins ◽  
Posterior Wall ◽  
The Novel ◽  
Median Treatment

Abstract Background Pulmonary vein isolation using cryotherapy is an established treatment for the management of patients with paroxysmal atrial fibrillation. Ablation using the commercially available balloon cryocatheter has been shown to create wide antral pulmonary vein isolation. A novel balloon cryocatheter (BCC) has been designed to maintain uniform pressure and size during ablation, potentially improving contact with the antral anatomy. The extent of ablation created using the novel BCC has not previously been established. Purpose To determine the anatomical extent of pulmonary vein isolation using electroanatomical mapping when performing catheter ablation for paroxysmal atrial fibrillation using the novel BCC. Methods Nine consecutive patients underwent pre-procedure computed tomography angiography of the left atrium to quantify the chamber dimensions. An electroanatomical map was created using the cryoablation system mapping catheter and a high definition mapping system. A bipolar voltage map was obtained following ablation to determine the extent of pulmonary vein isolation ablation. A volumetric technique was used to quantify the extent of vein and posterior wall electrical isolation in addition to traditional techniques for proving entrance and exit block. Results All patients had paroxysmal atrial fibrillation, mean age 56 years, 7 (78%) male. Electrical isolation was achieved for 100% of the pulmonary veins; mean total procedure time was 109 min (+/- 26 SD), and fluoroscopy time 14.9 min (+/- 2.4 SD). The median treatment applications per vein was one (range one - four), and median treatment duration 180 sec (range 180 -240). Left atrial volume 32 mL/m2 (+/- 7 SD), and mean left atrial posterior wall area 22 cm2 (+/- 4 SD). Data was available for quantitative assessment of the extent of ablation for eight patients. No lesions (0 of 32) were ostial in nature. The antral surface area of ablation was not statistically different between the left and right sided pulmonary veins (p 0.63), which were 5.9 (1.6 SD) and 5.4 (2.1 SD) cm2 respectively. In total 50% of the posterior left atrial wall was ablated.  Conclusion Pulmonary vein isolation using a novel BCC provides a wide and antral lesion set. There is significant debulking of the posterior wall of the left atrium. Abstract Figure.

A Stunning Left Atrial Appendage Thrombus

Cardiology ◽  
2016 ◽  
Vol 134 (4) ◽  
pp. 394-397
Author(s):  
Sajid Ali ◽  
Justin Ugwu ◽  
Yousuf Kanjwal
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Atrial Flutter ◽  
Pulmonary Vein ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Atrial Appendage ◽  
Transesophageal Echocardiogram ◽  
Left Atrial Appendage Thrombus

Background: Left atrial appendage thrombus formation is a known major complication of atrial fibrillation and atrial flutter which increases the risk of embolism and stroke. This risk of thrombosis is greatly increased with a lack of anticoagulation. After conversion to a normal sinus rhythm in these arrhythmias, the risk of thrombus formation in the left atrium persists through a phenomenon termed atrial myocardial stunning. Case: We present the case of a patient who previously underwent successful pulmonary vein isolation and was found to be in typical isthmus-dependent atrial flutter with a questionable recurrence of atrial fibrillation. The decision was made to return for atrial flutter ablation and for evaluation of prior pulmonary vein isolation. Initially, a transesophageal echocardiogram showed a normal ejection fraction, biatrial enlargement and no left atrial appendage thrombus. Ablation of the cavotricuspid isthmus was successfully accomplished with documented bidirectional block. A transesophageal echocardiogram probe was still in place prior to planned transseptal puncture for the evaluation of pulmonary veins. A large thrombus was now observed filling the left atrial appendage. Conclusion and Objective: Atrial stunning is a transient atrial contractile dysfunction that occurs whether sinus rhythm is restored spontaneously, electrically, pharmacologically or by ablation. We know after conversion that there is higher propensity to increased spontaneous echogenic contrast and decreased velocities; however, we do not have documented knowledge of exactly how soon after the conversion to a sinus rhythm a thrombus may be seen. We demonstrate a case of acute left atrial appendage thrombus formation immediately following the successful ablation of isthmus-dependent atrial flutter. Our report validates the belief that strategies of not interrupting anticoagulation prior to the conversion of these arrhythmias should be implemented.

scholarly journals Atrial Fibrillation Increases Production of Superoxide by the Left Atrium and Left Atrial Appendage

Circulation ◽  
2005 ◽  
Vol 112 (9) ◽  
pp. 1266-1273 ◽  
Author(s):  
Samuel C. Dudley ◽  
Nyssa E. Hoch ◽  
Louise A. McCann ◽  
Clegg Honeycutt ◽  
Laura Diamandopoulos ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Atrial Appendage
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