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

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.

Author(s):  
Liuyang Feng ◽  
Hao Gao ◽  
Nan Qi ◽  
Mark Danton ◽  
Nicholas A. Hill ◽  
...  

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.


Cardiology ◽  
1996 ◽  
Vol 87 (6) ◽  
pp. 537-544 ◽  
Author(s):  
Jer-Min Lin ◽  
Kwan-Lih Hsu ◽  
Juey-Jen Hwang ◽  
Yi-Heng Li ◽  
Yung-Zu Tseng

Author(s):  
Mario Salido ◽  
Marc Soriano ◽  
Estefanía Fernaández ◽  
Dabit Arzamendi ◽  
Alba Maestro ◽  
...  

2016 ◽  
Vol 31 (1) ◽  
pp. 26-28
Author(s):  
Rampada Sarker ◽  
Manoz Kumar Sarker ◽  
AM Asif Rahim ◽  
Abdul Khaleque Beg

Background: Open mitral operation in patients with massive left atrial thrombus still with high mortality due to intra-operative embolism. To prevent this mortality due to intra-operative embolism and to prevent this danger we practiced a surgical technique which includes careful handling of heart and obliteration of left ventricular cavity by bilateral compression.Method: We used this technique in patients of severe mitral stenosis with atrial thrombus during mitral valve replacement. Our technique was to obliterate the left ventricular cavity and thus keep the mitral cusps in a coapted position by placing gauge posterior to left ventricle and a compression over right ventricle by hand of an assistant with a piece of gauze. This obliteration prevented passage of fragments of left atrial thrombus towards collapsed left ventricle.Result: Before practicing this technique, 4 out 9 patients expired due to cerebral embolism . But after implementation of this technique in 17 patients no mortality or morbidity occurred.Conclusion: This technique of removal of left atrial thrombus during mitral valve replacement may be a safe procedure for preventing peroperative embolism.Bangladesh Heart Journal 2016; 31(1) : 26-28


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lei Chen ◽  
Changjiang Xu ◽  
Wensu Chen ◽  
Chaoqun Zhang

Abstract Background Thromboembolic events are the most serious complication of atrial fibrillation (AF), and the left atrial appendage (LAA) is the most important site of thrombosis in patients with AF. During the period of COVID-19, a non-invasive left atrial appendage detection method is particularly important in order to reduce the exposure of the virus. This study used CT three-dimensional reconstruction methods to explore the relationship between LAA morphology, LAA orifice area and its mechanical function in patients with non-valvular atrial fibrillation (NVAF). Methods A total of 81 consecutive patients with NVAF (36 cases of paroxysmal atrial fibrillation and 45 cases of persistent atrial fibrillation) who were planned to undergo catheter radiofrequency ablation were enrolled. All patients were examined by transthoracic echocardiography (TTE), TEE, and computed tomography angiography (CTA) before surgery. The LAA orifice area was obtained according to the images of CTA. According to the left atrial appendage morphology, it was divided into chicken wing type and non-chicken wing type. At the same time, TEE was performed to determine left atrial appendage flow velocity (LAAFV), and the relationship between the left atrial appendage orifice area and LAAFV was analyzed. Results The LAAFV in Non-chicken wing group was lower than that in Chicken wing group (36.2 ± 15.0 cm/s vs. 49.1 ± 22.0 cm/s, p-value < 0.05). In the subgroup analysis, the LAAFV in Non-chicken wing group was lower than that in Chicken wing group in the paroxysmal AF (44.0 ± 14.3 cm/s vs. 60.2 ± 22.8 cm/s, p-value < 0.05). In the persistent AF, similar results were observed (29.7 ± 12.4 cm/s vs. 40.8 ± 17.7 cm/s, p-value < 0.05). The LAAFV in persistent AF group was lower than that in paroxysmal AF group (34.6 ± 15.8 cm/s vs. 49.9 ± 20.0 cm/s, p-value < 0.001). The LAAFV was negatively correlated with left atrial dimension (R = − 0.451, p-value < 0.001), LAA orifice area (R= − 0.438, p-value < 0.001) and left ventricular mass index (LVMI) (R= − 0.624, p-value < 0.001), while it was positively correlated with LVEF (R = 0.271, p-value = 0.014). Multiple linear regression analysis showed that LAA morphology (β = − 0.335, p-value < 0.001), LAA orifice area (β = −  0.185, p-value = 0.033), AF type (β = − 0.167, p-value = 0.043) and LVMI (β = − 0.465, p-value < 0.001) were independent factors of LAAFV. Conclusions The LAA orifice area is closely related to the mechanical function of the LAA in patients with NVAF. The larger LAA orifice area and LVMI, Non-chicken wing LAA and persistent AF are independent predictors of decreased mechanical function of LAA, and these parameters might be helpful for better management of LA thrombosis.


Author(s):  
Samuel Heuts ◽  
John Heijmans ◽  
Mark La Meir ◽  
Bart Maesen

Introduction Although left atrial appendage (LAA) obliteration is the cornerstone of stroke prevention in surgical treatment of atrial fibrillation (AF), little is known about its direct impact on hemodynamics. In the current pilot study, we evaluated the hemodynamic effect of LAA closure by clipping in patients undergoing hybrid AF ablation. Methods Seven patients with paroxysmal or persistent AF were included. Hemodynamic and intracardiac pressure measurements such as systemic, pulmonary artery (PA), central venous and LA pressure, cardiac output and indexed left ventricular stroke volume (LVSVi) were measured directly before (T0) and after (T1), and 10 minutes after (T2) LAA closure. Results Of the 7 patients (median 66 yrs), 5 were in AF at the time of incision. There were no differences between T0 and T1, T1 and T2 and T0 and T2 for LA pressure, mean PA pressure, LVSVi and other hemodynamic parameters such as central venous oxygenation and pressure, or systemic arterial pressure. Conclusion In this pilot study, the direct hemodynamic effect of LAA closure is evaluated for the first time. Clipping of the LAA is safe and does not directly affect hemodynamic and intracardiac pressures.


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