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The beat-to-beat decay of cardiac contractility from highly potentiated levels is bi-exponential

Noble, Mark I. M. ; Arlock, Per LU ; Wohlfart, Björn LU and Drake-Holland, Angela J. (2006) In Journal of Biomechanics 39(14). p.2657-2664
Abstract
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... (More)
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. (c) 2005 Elsevier Ltd. All rights reserved. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
force-interval, myocardium, sarcoplasmic reticulum, handling, cardiac calcium, post-extrasystolic potentiation, voltage clamp, relationship, sodium-calcium exchange, excitation-contraction coupling
in
Journal of Biomechanics
volume
39
issue
14
pages
2657 - 2664
publisher
Elsevier
external identifiers
  • wos:000241850100013
  • scopus:33749252754
ISSN
1873-2380
DOI
10.1016/j.jbiomech.2005.08.011
language
English
LU publication?
yes
id
dcf159cc-214c-4d69-a56c-05e1cdd868b6 (old id 377016)
date added to LUP
2016-04-01 11:41:38
date last changed
2021-02-17 05:17:14
@article{dcf159cc-214c-4d69-a56c-05e1cdd868b6,
  abstract     = {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. (c) 2005 Elsevier Ltd. All rights reserved.},
  author       = {Noble, Mark I. M. and Arlock, Per and Wohlfart, Björn and Drake-Holland, Angela J.},
  issn         = {1873-2380},
  language     = {eng},
  number       = {14},
  pages        = {2657--2664},
  publisher    = {Elsevier},
  series       = {Journal of Biomechanics},
  title        = {The beat-to-beat decay of cardiac contractility from highly potentiated levels is bi-exponential},
  url          = {http://dx.doi.org/10.1016/j.jbiomech.2005.08.011},
  doi          = {10.1016/j.jbiomech.2005.08.011},
  volume       = {39},
  year         = {2006},
}