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.

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.

Probe for production and measurement of acute mitral regurgitant flow in dog

1976 ◽  
Vol 40 (2) ◽  
pp. 256-259
Author(s):  
A. G. Kleber ◽  
R. Simon ◽  
W. Rutishauser
Keyword(s):  
Mitral Valve ◽  
Left Atrial ◽  
Cardiac Cycle ◽  
Left Atrial Appendage ◽  
Left Ventricular ◽  
Small Extent ◽  
Phase Lag ◽  
Regurgitant Flow ◽  
Acute Mitral Regurgitation ◽  
Flow Through

A probe for production and measurement of acute mitral regurgitation in dogs is described. It consists of a tube that is introduced into the mitral valve through the left atrial appendage. Regurgitant flow through the tube is measured by an electromagnetic device. Variation of flow and zero flow are achieved by narrowing or occluding the tube with a rubber cuff. In animals weighing 30–50 kg, the probe does not produce significant mitral stenosis and the mitral leaflets fit closely around the probe during ventricular systole. The instantaneous relationship between mitral regurgitant flow (MRF) and the gradient between left ventricular and left atrial pressure shows a marked delay of MRF at the beginning and end of regurgitation. This delay can be attributed to some extent to electrical phase lag and to the small movement of the probe relative to the mitral valve during the cardiac cycle. Measurement of regurgitant stroke volume is affected by this movement only to a small extent.

The ligament of Marshall as a parasympathetic conduit

2007 ◽  
Vol 293 (3) ◽  
pp. H1629-H1635 ◽  
Author(s):  
Joseph S. Ulphani ◽  
Rishi Arora ◽  
Jack H. Cain ◽  
Roger Villuendas ◽  
Sharon Shen ◽  
...  
Keyword(s):  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Pulmonary Veins ◽  
Stellate Ganglion ◽  
Nerve Fibers ◽  
Atrial Appendage ◽  
Cholinergic Nerves ◽  
Left Vagus

The objective of the study was to investigate the morphology, distribution, and electrophysiological profile of the autonomic fibers that innervate the ligament of Marshall (LOM). Gross anatomical dissections were performed in 10 dogs. Sections of the left vagus nerve, left stellate ganglion, and the LOM were immunostained to identify adrenergic and cholinergic nerves. Hearts were also stained for acetylcholinesterase to identify epicardial cholinergic nerves. In vivo electropyhsiological studies were performed in another 10 dogs before and after LOM ablation. The anatomical examination revealed that the LOM is innervated by a branch of the left vagus. Immunohistochemistry confirmed that these nerve bundles are predominantly cholinergic (cholinergic-to-adrenergic ratio of 12.6 ± 3.9:1). Cholinergic nerves originating in the LOM were found to innervate surrounding left atrial structures, including the pulmonary veins, left atrial appendage, coronary sinus, and posterior left atrial fat pad. Ablation of the LOM significantly attenuated effective refractory period shortening at distant sites, such as pulmonary veins and left atrial appendage, in response to vagal stimulation (vagal-induced ERP decrease in the left atrium: baseline vs. postablation = 17 vs. 4%; P = 0.0056). In conclusion, the LOM contains a predominance of cholinergic nerve fibers. Cholinergic fibers arising from the LOM innervate surrounding structures and contribute to the electrophysiological profile of the left atrium. These findings may provide a basis for the role of the LOM in the genesis and maintenance of atrial fibrillation.

scholarly journals P1312 Implications of a large atrial roof thrombus

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
P Fountoulakis ◽  
E Hamodraka ◽  
A Siama ◽  
A Tsoukas ◽  
A J Manolis
Keyword(s):  
Atrial Fibrillation ◽  
Mitral Valve ◽  
Transesophageal Echocardiography ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Posterior Wall ◽  
Mitral Valve Stenosis ◽  
Systemic Embolism ◽  
Intracardiac Thrombi

Abstract Funding Acknowledgements No funding Introduction Rheumatic heart disease is the most common cause of mitral valve stenosis. Rheumatic valve disease presents a strong predisposing factor to intracardiac thrombi formation in the left atrium, particularly when there is a background of atrial fibrillation. The predominant location for thrombus creation is the left atrial appendage, due to its morphology, and rarely the free wall or roof of the left atrium. In either case, the presence of intracardiac thrombi in the left cardiac cavities poses a severe risk factor for systemic embolism which can prove detrimental for the patient leading to increased morbidity and mortality. Transesophageal echocardiography remains the gold standard for screening of the left atrium. Case presentation We present the case of a 72 year old woman who was admitted to the Emergency Department of our Hospital because of palpitations and progressive weakness over the last month. She had a known history of rheumatic mitral valve stenosis and chronic atrial fibrillation under standard anticoagulant treatment with acenocoumarol. Methods - Results: On admission, the patient was hemodynamically stable without signs of heart failure. The electrocardiogram revealed atrial fibrillation with a ventricular rate of approximately 135 bpm. Chest X-Ray did not demonstrate any signs of pulmonary congestion. Blood tests were normal, except from a subtherapeutic INR 1.3. Transthoracic echocardiography depicted a suspicious large echogenous mass located on the posterior wall of the left atrium. Furthermore, there was severe mitral valve stenosis with calcification of the mitral annulus as well as reduced mobility of the leaflets (Mitral Valve Area ∼0.8 cm2, Mean gradient = 15 mmHg) and mild aortic valve stenosis. The left ventricle had normal dimensions and good overall systolic function. Systolic pulmonary pressure was estimated at 50 mmHg. Transesophageal echocardiography confirmed the presence of a large echogenous mass (2,6 x 2,9 cm) located on the posterior wall of the left atrium between the right and left pulmonary veins as well as another mass at the left atrial appendage. Contrast echocardiography ensued, which revealed no absorption of the contrast medium by the mass thus suggesting a lesion with no vascularity, compatible with thrombus. Furthermore there was diffuse slow flow within the left atrium (smoke) indicating blood stasis. The patient was treated with a cardioselective beta blocker and combination of aspirin and acenocoumarol with a target INR of 2,5-3 and was referred for cardiothoracic consultation. Conclusion/Discussion: We describe a rare case of moderate mitral stenosis with presence of a large thrombus with mobile parts in an unusual location. In this setting the indication for surgery (mitral valve replacement) is upgraded since there is increased risk of thrombus detachment and debilitating systemic embolism. Abstract P1312 Figure.

Effect of increased left atrial pressure on breathing frequency in anesthetized dog

1990 ◽  
Vol 69 (6) ◽  
pp. 1973-1980 ◽  
Author(s):  
T. C. Lloyd
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Pulmonary Veins ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Left Heart ◽  
Breathing Frequency ◽  
Anesthetized Dogs ◽  
The Right

Distension or loading of the isolated canine left heart caused reflex tachypnea in prior studies. The object of the present effort was to explore the possibility that this depended primarily on atrial distension. Cardiopulmonary bypass perfusion and ligation of pulmonary veins were used to isolate the left-heart chambers of anesthetized dogs. Simultaneous distension of the beating left atrium and fibrillating ventricle stimulated breathing frequency (f), whereas isolated ventricular distension did not. At other times, intervals of atrial fibrillation were imposed under two different conditions: 1) while the right heart and lungs were bypassed and systemic perfusion was provided by the left ventricle using blood returned to the left atrium by pump and 2) while the ventricles fibrillated and systemic perfusion was supplied directly by the pump. Atrial fibrillation increased left atrial pressure and stimulated f in condition 1. In condition 2, f increased only if fibrillation was associated with a rise in left atrial pressure. Vagal cooling blocked the effect of fibrillation. I conclude that left atrial distension may initiate reflex tachypnea.

scholarly journals Left Atrial Volume Correlates with Mitral Annulus Size: An MDCT Study

2021 ◽  
Vol 11 (23) ◽  
pp. 11329
Author(s):  
Gabriel Cismaru ◽  
Iulia Valean ◽  
Mihnea Cantemir Zirbo ◽  
Alexandru Tirpe ◽  
Andrei Cismaru ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Atrium ◽  
Left Atrial ◽  
Three Dimensional ◽  
Left Atrial Volume ◽  
Persistent Atrial Fibrillation ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Atrial Volume ◽  
Minimum Age

Aim: Although the association between left ventricular dilation and mitral annulus dilation is well understood, the potential variation in the size of the mitral annulus during dilation of the left atrium is currently unknown. In order to investigate the link between the two variables, we used multidetector computed tomography (MDCT) and looked at patients who had a dilated left atrium, assessing if the mitral valve also dilates. Materials and Methods: The study included 107 patients with paroxysmal and persistent atrial fibrillation, in whom catheter ablation was performed using pulmonary vein isolation ± atrial substrate modification. Eighty patients were male (74.8%), with a mean age of 55.8 years (±9.87 with a minimum age of 26 years and a maximum age of 79 years), of which 57.1% had paroxysmal AF and the rest had persistent fibrillation. All the patients underwent multiple-detector CT (MDCT) with contrast medium before the ablation. CT images were integrated into the three-dimensional mapping system CARTO 3, after which the diameters of the mitral annulus, area, and circumference were measured. Left atrial size was evaluated by measuring the diameters, area, and volume. Results: The left atrial area was 247 ± 65.7 cm2 and the left atrial volume was 139 ± 56.3 mL. The transverse mitral annulus (MA) was 29.9 ± 5.3 mm and the longitudinal diameter was 41.9 ± 7.6 mm. The MA circumference and area were 15.0 ± 3.5 cm and 14.2 ± 4.6 cm2, respectively. The following statistically significant correlation was identified between the dimensions of the mitral annulus and the diameters of the left atrium: the transverse mitral annulus correlates with the antero-posterior (AP) LA diameter (R = 0.594, p < 0.01) and the longitudinal MA diameter correlates with the latero-lateral (LL) LA diameter (R = 0.576, p < 0.01). Furthermore, the MA area correlates with the LA volume (R = 0.639, p < 0.001). Conclusions: The volume of the left atrium correlates with the area of the mitral annulus. In patients with paroxysmal and persistent AF, an increase in left atrial dimensions is further associated with an increase in mitral valve dimensions.

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 Acute Mitral Regurgitation Secondary to Spontaneous Left Atrial Appendage Occluder Migration

2021 ◽  
Author(s):  
Mario Salido ◽  
Marc Soriano ◽  
Estefanía Fernaández ◽  
Dabit Arzamendi ◽  
Alba Maestro ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Atrial Appendage ◽  
Acute Mitral Regurgitation
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