Contraction-excitation feedback in an ejecting whole heart model – dependence of action potential duration on left ventricular diastolic and systolic pressures

Study objective – Contraction-excitation feedback may play a role in arrhythmogenesis in heart failure. The aims of this study were to determine whether contraction-excitation feedback has a significant effect on action potential duration within a physiological range of pressures, and to investigate...

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Bibliographic Details
Published in:Cardiovascular research 1991-04, Vol.25 (4), p.343-352
Main Authors: Coulshed, David S, Cowan, J Campbell
Format: Article
Language:English
Subjects:
Action Potentials - physiology
Animals
arrhythmias
Arrhythmias, Cardiac - metabolism
Arrhythmias, Cardiac - physiopathology
Biological and medical sciences
Blood Pressure - physiology
Cardiac Output - physiology
Cardiology. Vascular system
Coronary Circulation
Feedback
Guinea Pigs
Heart
Heart - physiopathology
heart failure
Heart failure, cardiogenic pulmonary edema, cardiac enlargement
isolated hearts
Lactates - biosynthesis
Medical sciences
Models, Cardiovascular
Myocardial Contraction - physiology
Myocardium - metabolism
Regional Blood Flow - physiology
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Summary:Study objective – Contraction-excitation feedback may play a role in arrhythmogenesis in heart failure. The aims of this study were to determine whether contraction-excitation feedback has a significant effect on action potential duration within a physiological range of pressures, and to investigate the individual effects of left ventricular end diastolic and peak systolic pressures on action potential duration. Design – A new model was developed for studying contraction-excitation feedback in a physiologically electing isolated heart preparation. Hearts were perfused via the left atrium, electing against an aortic afterload. By varying left atrial and aortic pressures, left ventricular end diastolic pressure and left ventricular peak systolic pressure were controlled independently. Intracellular potentials were recorded from the epicardium. Experimental material – Hearts (n = 33) were obtained from guinea pigs weighing 300-350 g. Measurements and main results – Increasing left ventricular end diastolic pressure from 0.3 to 1.1 kPa (2.2 to 8.3 mm Hg), at constant left ventricular peak systolic pressure, shortened action potential duration by 11.3(SEM 1.5) ms (p
ISSN:0008-6363
1755-3245
DOI:10.1093/cvr/25.4.343