Early afterdepolarizations and cardiac arrhythmias
نویسندگان
چکیده
منابع مشابه
QTU prolongation and polymorphic ventricular tachyarrhythmias due to bradycardia-dependent early afterdepolarizations. Afterdepolarizations and ventricular arrhythmias.
Polymorphic ventricular tachyarrhythmias occurred spontaneously during bradycardia in dogs given the inotropic polypeptide anthopleurin-A (AP-A). The arrhythmia was investigated in in vitro and in vivo experiments. In in vitro experiments, AP-A (50 micrograms/l) produced bradycardia-dependent prolongation of action potential duration that was more pronounced in Purkinje than in muscle fibers. O...
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Clinical studies have shown that sudden death is initiated by an illtimed propagated ectopic beat that leads to fibrillation. –4 However, the mechanism underlying these focal excitations is not completely understood. Experimental studies have demonstrated that abnormal calcium (Ca2+) cycling is a critical factor in the development of focal excitations. 9 These excitations can be caused by spont...
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Excitable cells can exhibit complex patterns of oscillations, such as spiking and bursting. In cardiac cells, pathological voltage oscillations, called early afterdepolarizations (EADs), have been widely observed under disease conditions, yet their dynamical mechanisms remain unknown. Here, we show that EADs are caused by Hopf and homoclinic bifurcations. During period pacing, chaos always occu...
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Early afterdepolarizations (EADs) are secondary voltage depolarizations during the repolarizing phase of the action potential, which can cause lethal cardiac arrhythmias. The occurrence of EADs requires a reduction in outward current and/or an increase in inward current, a condition called reduced repolarization reserve. However, this generalized condition is not sufficient for EAD genesis and ...
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Unlike the brief action potentials (APs) in skeletal myo cytes or neurons, the human cardiac AP takes 100s of milliseconds to repolarize the cell. This slow repolar ization is essential for proper excitation–contraction coupling in cardiac muscle, and precise control of AP duration contributes to electrical stability. Under vari ous pathological conditions, often when the AP dura tion is pr...
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ژورنال
عنوان ژورنال: Heart Rhythm
سال: 2010
ISSN: 1547-5271
DOI: 10.1016/j.hrthm.2010.09.017