Scroll Waves in 3D Virtual Human Atria: A Computational Study

Kharche, Sanjay; Seemann, Gunnar; Leng, Joanna; Holden, Arun V.; Garratt, Clifford J.; Zhang, Henggui

doi:10.1007/978-3-540-72907-5_14

Cited by 12 publications

(11 citation statements)

References 17 publications

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“…The integrative action of these cellular and tissue properties reduces the wavelength of atrial excitation waves allowing atria to sustain high rate reentrant excitation waves. This pro-arrhythmic mechanism is similar to that of AF-induced electrical remodeling on some ion channels [3,11,14] and gain-in-function of I K1 arising from KCNJ2 gene mutation [4]. This study substantiates the link between an elevated Hcy concentration and incidence of AF in some patients.…”

Section: Conclusion and Discussionsupporting

confidence: 75%

Effects of elevated Homocysteine hormone on electrical activity in the human atrium: A simulation study

Law

Kharche

Stott

et al. 2009

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Atrial fibrillation (AF) accounts for a large proportion of healthcare expenditure world wide. Mechanisms underlying the genesis and maintenance of AF are still poorly understood. Though AF is largely thought to be caused and perpetuated by dysfunctions of cellular ion channels, disrupted intercellular gap junctional electrical coupling, and/or structural changes in the atria, it is also associated with abnormal secretion of hormones, such as a high level of Homocysteine (Hcy). It was found that a high concentration Hcy induces electrical remodeling of ion channels in human atrial cells that include the ultra rapid potassium, inward rectifier potassium and transient outward potassium currents. Such Hcy-induced ion channel remodeling in repolarising potassium currents has been hypothesized to be pro-arrhythmic. In this study, we carried out multi-scale simulations to evaluate the effects of Hcy-induced changes in potassium currents on the electrical activity of human atrium at single cell, 1D strand of tissue, and 3D anatomical models. We found that high Hcy concentration produced marked changes in atrial action potentials, including a more hyperpolarized resting potential, elevated plateau potential during early stages of repolarization and abbreviated action potential duration (APD). Losses in rate dependent accommodation of APD and effective refractory period were observed. In the tissue models, high Hcy concentration slowed down atrial excitation conduction at low rates, but facilitated it at high rates. Simulated re-entrant scroll waves in the 3D model self-terminated under Control condition, but sustained under high Hcy condition. These results collectively demonstrate the pro-arrhythmic effects of a high level Hcy in promoting and sustaining AF.

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Section: Conclusion and Discussionsupporting

confidence: 75%

Effects of elevated Homocysteine hormone on electrical activity in the human atrium: A simulation study

Law

Kharche

Stott

et al. 2009

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

View full text Add to dashboard Cite

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“…Images in Figure 5 were produced using diamond‐shaped glyphs, each of which was colour coded with a scalar value, namely the value of voltage at that location. We developed another visualization pipeline using the JAVA‐based modular software RAVE 17 and the results are given in 18. AVS and RAVE can be used as parallel visualization engines.…”

Section: Hpv Of Large Data Setsmentioning

confidence: 99%

Talking about death: Implementing peer discussion as a coping mechanism to overcome fears about dissection, death, and dying

Kotzé

Mole

2012

Anatomical Sciences Ed

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Many studies have reported on the perceptions of medical students toward dissection. It is important to understand the feelings and symptoms experienced during dissection so that they can be adequately handled. Prior to dissection, first year students are given lectures on aspects of dissection, death and dying, and death rituals in various cultures. Two separate questionnaires, one given during the first week of dissection and another given one month into the program were then completed anonymously by dissection groups. The questions were designed to be open-ended, thereby encouraging group discussion amongst students. The questionnaires were used to determine the perception of students to dissection and to discover if these perceptions change during the dissection program. The first questionnaire revealed that students do experience fears and anxiety prior to and at the beginning of dissection; however, most of these fears dissipated by the time of the second questionnaire. One month into dissection students cited talking to peers as their main coping mechanism and fewer students mentioned emotional detachment from their cadaver as a coping mechanism, as was the case in the first questionnaire. Dissection was perceived as a positive experience by our student cohort and most students cited the main advantage of dissection as the ability to visualize organs in three dimensions. The comprehensive answers received from the students indicated that thorough discussion of feelings amongst peers occurred, introducing students to an important coping mechanism at an early stage of their learning.

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“…The difference in the maximal and minimal values of the S1-S2 intervals that produced uni-directional propagation defined the VW. Re-entrant waves in 2D homogenous sheets of tissue (37 mm x 37 mm) were initiated using standard S1-S2 protocol [9]. and scroll wave re-entry in the 3D homogenous model was initiated in the largest contiguous surface of the right atrium using a cross-field protocol similar to that used in 2D idealized sheets of atrial tissue.…”

Section: Pcl (Ms)mentioning

confidence: 99%

Stability of scroll excitation waves in human atria during fibrillation: A computational study

Kharche

Garratt

Holden

et al. 2007

2007 Computers in Cardiology

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We computationally evaluated the functional roles of atrial fibrillation induced electrical remodelling (AFER)on IntroductionAtrial fibrillation (AF) affects the aged population and accounts for about 1% of the total National Health Service expenditure [1] in the UK alone and also has a large prevalence in the USA [2]. AF is the most common sustained arrhythmia leading to thromboembolism and heart failure among other debilitating cardiac complications. AF is characterized by irregular re-entrant electrical propagations in the atria. Chronic AF induced electrical remodeling (AFER) of membrane ionic channels in individual atrial cells has been recently studied in two experimental studies [3,4], and has been proposed as a major contributor underlying persistent as it shortens action potential duration (APD 90 ), reduces atrial conduction velocity (CV) leading to stability of reentrant excitation. In addition, anatomical obstacles due to the opening holes of blood vessels (e.g. superior vena cava (SVC) and pulmonary veins) may provide a secondary mechanism to sustain AF.In this paper, we studied the effects of AFER on the electrical activities in atrial cells and spatially extended atrial tissue. Dynamical behaviour of scroll waves in a 3D homogenous anatomical model were characterized. Our study has shown that AFER alone has a major effect on atrial conduction and scroll wave dynamics, which helps sustain AF. This study provides insights to understand how AF begets AF, by which paroxysmal AF transient to chronic AF due to AF-induced AFER.

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Scroll Waves in 3D Virtual Human Atria: A Computational Study

Cited by 12 publications

References 17 publications

Effects of elevated Homocysteine hormone on electrical activity in the human atrium: A simulation study

Effects of elevated Homocysteine hormone on electrical activity in the human atrium: A simulation study

Talking about death: Implementing peer discussion as a coping mechanism to overcome fears about dissection, death, and dying

Stability of scroll excitation waves in human atria during fibrillation: A computational study

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