کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
874693 | 910346 | 2006 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The beat-to-beat decay of cardiac contractility from highly potentiated levels is bi-exponential
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی پزشکی
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![عکس صفحه اول مقاله: The beat-to-beat decay of cardiac contractility from highly potentiated levels is bi-exponential The beat-to-beat decay of cardiac contractility from highly potentiated levels is bi-exponential](/preview/png/874693.png)
چکیده انگلیسی
In order to determine the mode of beat-to-beat decay of contractility from very high levels, we studied the beat-by-beat decay of cardiac contractility following potentiation. Such decay curves are normally analysed using a mono-exponential decay function, which assumes that a fixed fraction of activator calcium ions is recirculated from one beat to the next. We postulated that there might be deviations from such a mono-exponential expression at high levels of contractility. In single sucrose-gap voltage clamp experiments of isolated ferret papillary muscle, we obtained very high contractility by potentiation due to prolonged depolarisations. We found a bi-exponential decay in 9 of 11 muscles studied, in which the initial decay is much faster than the subsequent slower decay, as judged by residual variance of least-squares exponential fitting and by analysis of covariance using a linear equation (force of beat versus force of previous beat), p=0.0089. In the slower decay period (physiological range), the decay was identical to that following post-extrasystolic potentiation in the same muscles studied with conventional stimulation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Biomechanics - Volume 39, Issue 14, 2006, Pages 2657-2664
Journal: Journal of Biomechanics - Volume 39, Issue 14, 2006, Pages 2657-2664
نویسندگان
Mark I.M. Noble, Per Arlock, Bjorn Wohlfart, Angela J. Drake-Holland,