Effect of fiber orientation on propagation: electrical mapping of genetically altered mouse hearts

Punske, Bonnie B.; Taccardi, Bruno; Steadman, B.W.; Ershler, Philip R.; England, Alice H.; Valencik, Maria L.; McDonald, John A.; Litwin, Sheldon E.

doi:10.1016/j.jelectrocard.2005.06.097

Cited by 34 publications

(25 citation statements)

References 16 publications

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“…The basal posterior wall is the last region to be activated, which occurs during the down-slope of the R-wave (36). The timing and sequence of electrical excitation in the ventricles is influenced by the impulse propagating through the His-Purkinje system and the anistropic nature of myocardium where propagation velocities are faster along rather than across the fibers (35,37). Higher velocities along the fiber direction are partially attributed to a high density of gap junctions (connection sites allowing the passage of ions from cell to cell) concentrated at the intercalated disks in the longitudinal direction (as compared to cross-fiber gap junction densities) (38).…”

Section: Electrical Sequence Depolarizationmentioning

confidence: 99%

“…Higher velocities along the fiber direction are partially attributed to a high density of gap junctions (connection sites allowing the passage of ions from cell to cell) concentrated at the intercalated disks in the longitudinal direction (as compared to cross-fiber gap junction densities) (38). As a consequence, the electrical wavefront travels from the endocardium towards the epicardium in a clockwise rotation, along the orientation of the myofibers within the LV wall (37).…”

Section: Electrical Sequence Depolarizationmentioning

confidence: 99%

See 1 more Smart Citation

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Sengupta

Krishnamoorthy

Kořínek

et al. 2007

Journal of the American Society of Echocardiography

283

196

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Tissue Doppler imaging (TDI) and TDI-derived strain imaging are robust physiologic tools used for the noninvasive assessment of regional myocardial function. Due to high temporal and spatial resolution, regional function can be assessed for each phase of the cardiac cycle and within the transmural layers of the myocardial wall. Newer techniques that measure myocardial motion by speckle tracking in grayscale images have overcome the angle dependence of TDI strain, allowing for measurement of 2-dimensional strain and cardiac rotation. TDI, TDI strain, and speckle tracking may provide unique information that deciphers the deformation sequence of complexly oriented myofibers in the left ventricular wall. The data are, however, limited. This review examines the structure and function of the left ventricle relative to the potential clinical application of TDI and speckle tracking in assessing the global mechanical sequence of the left ventricle in vivo.The spiral arrangement of muscle fibers in the heart is reminiscent of spiral and vortex patterns in nature, ranging from small organelles and whirlpools to hurricanes and rotational patterns of the galaxies (1-5). Vortex patterns link two fundamental forms of motion that work in close balance: an inner, rapidly descending swirl and an outer, less rapid, ascending rotation (4) ( Fig. 1 A-C). These counterdirectional movements of a vortex produce suction and expulsion forces that have been exploited for designing energy efficient propellers and turbines (6). Likewise, experimental and mathematical modeling of the clockwise and counterclockwise spiral loops of myofibers in the left ventricle (LV) has shown that counterdirectional geometry provides an efficient distribution of regional stresses and strains (7). Conversely, altered ventricular geometry resulting from cardiac remodeling, regional myocardial dysfunction, or asynchronous conduction distort the efficiency of the loading and expulsion dynamics (8,9). In this review, we associate the LV myofiber architecture to the spatiotemporal sequence of regional deformations occurring during normal cardiac contraction and relaxation. We further elucidate experimental observations, which explore the application of tissue Doppler imaging (TDI) and 2-dimensional ultrasound speckle tracking for delineation of the synchronous mechanical shortening and lengthening sequences of the human LV.Address reprint requests to Marek Belohlavek, Division of Cardiovascular Diseases, Mayo Clinic, 13400 East Shea Boulevard Scottsdale, AZ 85259, E-mail address for author named in reprint line: Belohlavek.marek@mayo.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect th...

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Section: Electrical Sequence Depolarizationmentioning

confidence: 99%

Section: Electrical Sequence Depolarizationmentioning

confidence: 99%

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Sengupta

Krishnamoorthy

Kořínek

et al. 2007

Journal of the American Society of Echocardiography

283

196

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“…Taccardi et al [66] studied potential distribution maps of excitation and recovery obtained by extensive multi-electrode recordings in dogs at 1 ms intervals and showed that the electrical wave fronts followed the complex intramural pathways of myocardial fibers in a coil-like manner wound around a series of toroidal cores. More recent studies in the mouse heart have revealed a similar helical twisting of the potential wave front and shown profound alteration of activation patterns in transgenic mice with reduced expression of connexin 43 of gap junctions or a mutation of a5 integrin [67]. The helical pathway of the electrical activation is not the direct evidence for the above-mentioned coil pattern of myocardial fibers but it raises a challenging question.…”

mentioning

confidence: 98%

Leonardo da Vinci's flights of the mind must continue: cardiac architecture and the fundamental relation of form and function revisited

Coghlan

Hoffman

2006

European Journal of Cardio-Thoracic Surgery

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This overview addresses the remarkable efficiency of the mammalian heart as a pump of unique capacity to quickly vary output and ejection velocity and its relation to ventricular geometry, fiber architecture, integrity of collagen scaffold and microvasculature and appropriate electrical activation. The unique functional capacity of the ventricle depends critically on the organization of cardiac muscle fibers in layers of counter-wound helices encircling the ventricular cavity in a pattern that allows a special twisting motion during systole and early diastole, essential to the mechanical efficiency of the normal ventricle to eject and suction venous return. The important contribution of advances in imaging techniques is reviewed, especially magnetic resonance with tagging and tensor analysis to define fiber orientation; these measurements are made without the use of implanted devices that can distort structure and even impair function. The impact of loss of optimal fiber orientation and geometry of the ventricle as a result of diseases that cause heart failure is analyzed, along with the possibility of improvement by carefully planned surgical restoration of ventricular geometry. The very encouraging results yielded by these therapeutic strategies are critically dependent on a clear understanding of the relation of structure and function that our analysis attempts to promote. Simultaneously, there is full acknowledgment of the unanswered questions that are inevitable but equally essential to the continuing search that scientific progress depends on.

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“…В итоге это по-давляет нормальное, направленное против часовой стрелки вращение или даже вызывает противополож-но направленное движение. Как результат, происходит снижение скручивания, которое в силу этого является не только параметром, отражающим собственно функ-цию ЛЖ, но и указывает на тяжесть внутрижелудочко-вой диссинхронии [22][23][24][25]. Это нашло подтверждение в нашем исследовании, в наличии в подгруппе с БЛНПГ и аномальным вращением более высоких по-казателей диссинхронии ЛЖ, фактора, связывающего нарушение внутрижелудочкого проведения и наруше-ния механической функции сердца.…”

Section: Discussionunclassified

Diastolic function of the left ventricle in patients with cardiomyopathy and low ejection fraction: the role of torsion in left bundle branch block

Pavlyukova

Kuzhel

Matyushin

et al. 2016

Racionalʹnaâ farmakoterapiâ v kardiologii

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1 Научно-исследовательский институт кардиологии. 634012, Томск, ул. Киевская, 111а 2 Красноярский Государственный Медицинский Университет им. проф. В.Ф. Войно-Ясенецкого 660022, Красноярск, ул. Партизана Железняка, 1 3 Красноярская краевая больница №2. 660049, Красноярск, ул. Карла Маркса, 43Влияние блокады левой ножки пучка Гиса (БЛНПГ) на диастолическую функцию и процесс скручивания левого желудочка (ЛЖ) у пациентов с кардиомиопатиями оста-ется малоизученным. Цель. Изучить взаимосвязь диастолической функции и скручивания ЛЖ у больных кардиомиопатиями на фоне БЛНПГ и нормальным внутрижелудочковым прове-дением. Материал и методы. Обследовано 74 пациента с ишемической и дилатационной кардиомиопатиями с фракцией выброса ЛЖ <40%, разделенных на две группы: с узкими QRS и БЛНПГ (средняя продолжительность QRS 153 мс). Всем больным была выполнена эхокардиография с определением показателей гемодинамики, де-формации миокарда и скручивания. Результаты. Несмотря на существенно меньшие показатели скручивания ЛЖ у больных с БЛНПГ по сравнению с больными с нормальным QRS (3,24±3,35° и 5,87±3,83°, соответственно, p=0,013914) значимые различия в показателях диастолической функции отсутствовали. Несмотря на отсутствие различий в показателях, характери-зующих ремоделирование сердца, в подгруппе с аномальным вращением наблюдались существенно меньшие показатели скручивания, а также были отмечены из-менения в потоке легочных вен, характерные для высокого конечного диастолического давления ЛЖ. В группе больных с аномальным вращением систолическая фрак-ция наполнения левого предсердия составила 32,3±8,07%, тогда как в группе с физиологическим разнонаправленным вращением -53,1±10,1% (p=0,000226). Временной интервал задержки сокращения задней стенки составил 63,3±35,1 мс в сравнение с лицами с физиологическим вращением ЛЖ -8,0±17,9 мс (p=0,015922), что отражало большую степень механической диссинхронии. Заключение. БЛНПГ оказывает комплексное негативное воздействие на процесс электрической активации и сокращения ЛЖ, результатом которого было нарушение скручивания, механическая диссинхрония и ухудшение диастолической функции. В условиях нарушений внутрижелудочковой проводимости и очаговых нарушений локальной сократимости оценка потока в легочных венах, возможно, более точно отражает состояние диастолической функции. Ключевые слова: функция левого желудочка, эхокардиография, технология «след пятна», ротация левого желудочка, скручивание левого желудочка, диастолическая дисфункция, блокада левой ножки пучка Гиса, кардиомиопатия. (n=74) and LV ejection fraction <40% were included into the study and divided in two groups with narrow QRS complex and LBBB (the mean QRS duration = 153 ms). Echocardiography was performed in all patients with hemodynamic indices detection, and myocardium strain and torsion estimation. Results. The patients with LBBB showed less twisting, than patients without LBBB (3.24±3.35° and 5.87±3.83°, respectively, p=0.013914), but significant diastolic function differences between groups were absent. Despite the lack of...

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Effect of fiber orientation on propagation: electrical mapping of genetically altered mouse hearts

Cited by 34 publications

References 16 publications

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Left Ventricular Form and Function Revisited: Applied Translational Science to Cardiovascular Ultrasound Imaging

Leonardo da Vinci's flights of the mind must continue: cardiac architecture and the fundamental relation of form and function revisited

Diastolic function of the left ventricle in patients with cardiomyopathy and low ejection fraction: the role of torsion in left bundle branch block

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