scholarly journals Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Amr Al Abed ◽  
Tianruo Guo ◽  
Nigel H. Lovell ◽  
Socrates Dokos

A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically pacedin vitrorabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

2015 ◽  
Vol 17 (6) ◽  
pp. 282
Author(s):  
Suguru Ohira ◽  
Kiyoshi Doi ◽  
Takeshi Nakamura ◽  
Hitoshi Yaku

Sinus venosus atrial septal defect (ASD) is usually associated with partial anomalous pulmonary venous return (PAPVR) of the right pulmonary veins to the superior vena cava (SVC), or to the SVC-right atrial junction. Standard procedure for repair of this defect is a patch roofing of the sinus venosus ASD and rerouting of pulmonary veins. However, the presence of SVC stenosis is a complication of this technique, and SVC augmentation is necessary in some cases. We present a simple technique for concomitant closure of sinus venosus ASD associated with PAPVR and augmentation of the SVC with a single autologous pericardial patch.


2020 ◽  
Vol 13 (11) ◽  
pp. e238018
Author(s):  
Joana Carvalho ◽  
Mariana Maia ◽  
Ágata Mota ◽  
Teresa Martins

Here we report a case of a term newborn presenting with left palpebral ptosis, anisocoria and heterochromia as well as cleft palate and heart murmur. Congenital Horner syndrome was suspected and a thoracoabdominal CT scan was performed to rule out neuroblastoma. This revealed an anomalous drainage of right pulmonary veins to a collector that drains to the inferior vena cava, leading to the diagnosis of Scimitar syndrome. Echocardiogram showed an ostium secundum atrial septal defect, enlarged right chambers and a dilated coronary sinus due to a persistent left superior vena cava. The combination of Horner and Scimitar syndrome has never been described before. This case should encourage clinicians to use a multidisciplinary approach in order to guarantee an adequate diagnosis and management.


2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
I Marco Clement ◽  
R Eiros ◽  
R Dalmau ◽  
T Lopez ◽  
G Guzman ◽  
...  

Abstract Introduction The diagnosis of sinus venosus atrial septal defect (SVASD) is complex and requires special imaging. Surgery is the conventional treatment; however, transcatheter repair may become an attractive option. Case report A 60 year-old woman was admitted to the cardiology department with several episodes of paroxysmal atrial flutter, atrial fibrillation and atrioventricular nodal reentrant tachycardia. She reported a 10-year history of occasional palpitations which had not been studied. A transthoracic echocardiography revealed severe right ventricle dilatation and moderate dysfunction. Right volume overload appeared to be secondary to a superior SVASD with partial anomalous pulmonary venous drainage. A transesophageal echocardiography confirmed the diagnosis revealing a large SVASD of 16x12 mm (Figure A) with left-right shunt (Qp/Qs 2,2) and two right pulmonary veins draining into the right superior vena cava. Additionally, it demonstrated coronary sinus dilatation secondary to persistent left superior vena cava. CMR and cardiac CT showed right superior and middle pulmonary veins draining into the right superior vena cava 18 mm above the septal defect (Figures B and C). After discussion in clinical session, a percutaneous approach was planned to correct the septal defect and anomalous pulmonary drainage. For this purpose, anatomical data obtained from CMR and CT was needed to plan the procedure. During the intervention two stents graft were deployed in the right superior vena cava. The distal stent was flared at the septal defect level so as to occlude it while redirecting the anomalous pulmonary venous flow to the left atrium (Figure D). Control CT confirmed the complete occlusion of the SVASD without residual communication from pulmonary veins to the right superior vena cava or the right atrium (Figure E). Anomalous right superior and middle pulmonary veins drained into the left atrium below the stents. Transthoracic echocardiographies showed progressive reduction of right atrium and ventricle dilatation. The patient also underwent successful ablation of atrial flutter and intranodal tachycardia. She is currently asymptomatic, without dyspnea or arrhythmic recurrences. Conclusions In this case, multimodality imaging played a key role in every stage of the clinical process. First, it provided the diagnosis and enabled an accurate understanding of the patient’s anatomy, particularly of the anomalous pulmonary venous connections. Secondly, it allowed a transcatheter approach by supplying essential information to guide the procedure. Finally, it assessed the effectiveness of the intervention and the improvement in cardiac hemodynamics during follow-up. Abstract P649 Figure.


2013 ◽  
Vol 25 (1) ◽  
pp. 16-22 ◽  
Author(s):  
KOTARO FUKUMOTO ◽  
SEIJI TAKATSUKI ◽  
TAKEHIRO KIMURA ◽  
NOBUHIRO NISHIYAMA ◽  
KOJIRO TANIMOTO ◽  
...  

PEDIATRICS ◽  
1952 ◽  
Vol 9 (2) ◽  
pp. 152-166
Author(s):  
HARRY G. PARSONS ◽  
ANN PURDY ◽  
BRUCE JESSUP

The successful operations upon abnormalities of the outflow tracts of the heart suggest that surgical measures may also be applied to the correction of abnormal inflow tracts. Technically the anastomosis of veins to the auricle has been proved feasible in the experimental animal. Therefore, it should be possible to correct abnormally placed pulmonary veins in man. A wide variety of such anomalies occur. In 55 of 136 reported cases, all the oxygenated blood from the lungs was returned to the right heart through anomalous vessels. Thirty-five per cent of these cases of complete diversion were accompanied by other major cardiac defects. It is estimated that 50% or more of the return flow from the lungs must reach the right heart to produce clinical symptoms. Two cases are presented of persistence of the left superior vena cava which transmitted all the freshly oxygenated blood to the right auricle, by way of the left innominate and the right superior vena cava. The clinical picture was that of growth retardation, minimal cyanosis, a huge hyperactive heart, a loud left mesocardial systolic murmur, pulsating shadows in both upper pulmonary fields, and nearly identical oxygen-saturation of blood obtained from the right heart and femoral artery. One case is reported in which all the oxygenated blood from the lungs is carried to the right auricle by way of the ductus venosus. Surgical correction of the abnormality of these cases by transplantation of one or more of the veins would have been possible. However, no case known to the authors has yet been successfully corrected.


2021 ◽  
pp. 28-31
Author(s):  
Inkar Sagatov ◽  
Nurzhan Dosmailov

The article describes the types of correction of the supracardial form of abnormal drainage of the pulmonary veins. One of the methods of correcting this defect is the Warden operation, which includes: after sternotomy, connection of artificial circulation, cardioplegia, the superior vena cava is cut off, the proximal end is sutured. Next, a right atriotomy is performed, an anastomosis is formed using an autopericardial patch between the abnormal drainage and the left atrium through the ASD. Then an anastomosis is formed between the auricle of the right atrium and the distal end of the superior vena cava. As a result, blood from the abnormal pulmonary veins begins to drain into the left atrium through the ASD.


2014 ◽  
Vol 55 (6) ◽  
pp. 732-736 ◽  
Author(s):  
Jorge E Lopera ◽  
Murray Shapiro ◽  
Darlene Sanchez ◽  
Carolina Maya ◽  
Ghazwan Kroma ◽  
...  

1985 ◽  
Vol 248 (1) ◽  
pp. H61-H68 ◽  
Author(s):  
W. C. Randall ◽  
J. L. Ardell

From right thoracotomy (T4-T5), the canine heart was suspended in its pericardium to expose its major venous inputs. Vagal and sympathetic trunks were prepared for electrical stimulation (10-20 Hz, 5.0 ms, 3-5 V) before and after each separate denervation procedure. Vagal stimulation was instituted with and without concurrent atrial pacing. The following surgical interventions were performed. 1) The superior vena cava was cleared of connective and nervous tissues from the pericardial reflection caudally to the level of the right pulmonary artery. 2) The azygos vein was cleared, tied, and sectioned. 3) The right pulmonary veins were isolated and cleared intrapericardially. 4) The dorsal surface of the atria was dissected between the right and left pulmonary veins and painted with phenol. Each step in the procedure elicited successive stepwise deletion of parasympathetic influences on sinoatrial tissues of the canine heart with only minor ablation of sympathetic inputs. 5) Dissection of the triangular fat pad at the junction of the inferior vena cava and inferior left atrium eliminated the remaining parasympathetic efferent input to the heart with dramatic deletion of atrioventricular block during either left or right vagal stimulation, again with preservation of most of the sympathetic innervation. These experiments clearly demonstrate differential and selective inputs of parasympathetic pathways to sinoatrial (SAN) and atrioventricular (AVN) regions of the dog heart but relatively little interference with sympathetic distributions.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
Geran Kostecki ◽  
Yu Shi ◽  
Christopher Chen ◽  
Daniel H. Reich ◽  
Emilia Entcheva ◽  
...  

AbstractInteractions between cardiac myofibroblasts and myocytes may slow conduction after cardiac injury, increasing the chance of life-threatening arrhythmia. While co-culture studies have shown that myofibroblasts can affect cardiomyocyte electrophysiology in vitro, the mechanism(s) remain debatable. In this study, primary neonatal rat cardiac myofibroblasts were transduced with the light-activated ion channel Channelrhodopsin-2, which allowed acute and selective modulation of myofibroblast currents in co-cultures with cardiomyocytes. Optical mapping revealed that myofibroblast-specific optogenetically induced inward currents decreased conduction velocity in the co-cultures by 27±6% (baseline = 17.7±5.3 cm/s), and shortened the cardiac action potential duration by 14±7% (baseline = 161±11 ms) when 0.017 mW/mm2 light was applied. When light irradiance was increased to 0.057 mW/mm2, the myofibroblast currents led to spontaneous beating in 6/7 co-cultures. Experiments showed that optogenetic perturbation did not lead to changes in myofibroblast strain and force generation, suggesting purely electrical effects in this model. In silico modeling of optogenetically modified myofibroblast-cardiomyocyte co-cultures largely reproduced these results and enabled a comprehensive study of relevant parameters. These results clearly demonstrate that myofibroblasts are sufficiently electrically connected to cardiomyocytes to effectively alter macroscopic electrophysiological properties in this model of cardiac tissue.


Author(s):  
Lou Capecci ◽  
Richard D. Mainwaring ◽  
Inger Olson ◽  
Frank L. Hanley

Cor triatriatum may be associated with abnormalities of pulmonary venous anatomy. This case report describes a unique form of partial anomalous pulmonary venous connection. The patient presented at 5 weeks of age with symptoms of tachypnea and poor feeding. Echocardiography demonstrated cor triatriatum and partial anomalous pulmonary venous drainage of the right upper lung. The patient underwent urgent repair of cor triatriatum. It was elected to not address the partial anomalous pulmonary venous connection at that time. The patient returned at age 19 months for elective repair of the anomalous pulmonary venous connection. There was also a large vein connecting the right lower pulmonary veins to the superior vena cava. This was repaired by dividing the superior vena cava along a vertical axis to redirect the flow of the anomalous pulmonary veins through the connecting vein to the left atrium. This report describes the anatomy and surgical approach to a unique form of anomalous pulmonary venous connection.


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