Intracellular kinetics of the activator calcium of rat heart after ischemic arrest and cardioplegia

Quantitative comparison of right and left ventricles

J. S. Juggi, Nasrin Mesaeli, A. M. Yousof

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The effects of plain ischemia (34°C) and the protective role of hypothermia (20°C) alone or in combination with cardioplegia (St Thomas' Hospital [STH] or glucose-potassium-nifedipine [GPN]) on the intracellular kinetics of the activator calcium of cardiac muscle were quantified and compared from the interval-force behaviour (mechanical restitution) of right and left ventricles of the perfused rat heart. Plain ischemia caused a major depression in the restitution of force of contraction of both ventricles, deranged the mixed linear-exponential functions by significantly increasing the time constants of the fitted mechanical restitution curves (MRC) and altered the control right/left ventricle interval-force relationship. The right ventricle was found to be more susceptible to ischemic damage than the left ventricle, and its inotropic reserve was virtually abolished by 1 h of plain ischemia. Hypothermic preservation during ischemia improved the mechanical restitution, salvaged the inotropic reserve and optimized right/left ventricle interval-force relationship, but the time constants of the fitted MRCs were still prolonged. However, both the cardioplegic formulations were equally effective in normalizing the time constants of the fitted curves. In general, right ventricle functions were better preserved by STH cardioplegia and left ventricle functions were better preserved by GPN cardioplegia. Cardioplegic interventions did not further improve the ventricular inotropic reserve compared with hypothermic preservation. Additional beneficical effects of cardioplegic formulations were directed towards stabilizing the linear-exponential functions and hence restitution of force of contraction. Interval-force behaviour of right and left ventricles, as documented in this study, provides the funtional approach for quantification of the cellular kinetics of activator calcium in the intact heart under globally ischemic conditions.

Original languageEnglish
Pages (from-to)387-395
Number of pages9
JournalCanadian Journal of Cardiology
Volume8
Issue number4
Publication statusPublished - 1992
Externally publishedYes

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Induced Heart Arrest
Heart Ventricles
Calcium
Ischemia
Nifedipine
Potassium
Glucose
Hypothermia
Myocardium

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

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title = "Intracellular kinetics of the activator calcium of rat heart after ischemic arrest and cardioplegia: Quantitative comparison of right and left ventricles",
abstract = "The effects of plain ischemia (34°C) and the protective role of hypothermia (20°C) alone or in combination with cardioplegia (St Thomas' Hospital [STH] or glucose-potassium-nifedipine [GPN]) on the intracellular kinetics of the activator calcium of cardiac muscle were quantified and compared from the interval-force behaviour (mechanical restitution) of right and left ventricles of the perfused rat heart. Plain ischemia caused a major depression in the restitution of force of contraction of both ventricles, deranged the mixed linear-exponential functions by significantly increasing the time constants of the fitted mechanical restitution curves (MRC) and altered the control right/left ventricle interval-force relationship. The right ventricle was found to be more susceptible to ischemic damage than the left ventricle, and its inotropic reserve was virtually abolished by 1 h of plain ischemia. Hypothermic preservation during ischemia improved the mechanical restitution, salvaged the inotropic reserve and optimized right/left ventricle interval-force relationship, but the time constants of the fitted MRCs were still prolonged. However, both the cardioplegic formulations were equally effective in normalizing the time constants of the fitted curves. In general, right ventricle functions were better preserved by STH cardioplegia and left ventricle functions were better preserved by GPN cardioplegia. Cardioplegic interventions did not further improve the ventricular inotropic reserve compared with hypothermic preservation. Additional beneficical effects of cardioplegic formulations were directed towards stabilizing the linear-exponential functions and hence restitution of force of contraction. Interval-force behaviour of right and left ventricles, as documented in this study, provides the funtional approach for quantification of the cellular kinetics of activator calcium in the intact heart under globally ischemic conditions.",
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T1 - Intracellular kinetics of the activator calcium of rat heart after ischemic arrest and cardioplegia

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AU - Mesaeli, Nasrin

AU - Yousof, A. M.

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