Journal article
Effect of Coronary Hyperemia on Emax and Oxygen Consumption in Blood-Perfused Rabbit Hearts: Energetic Consequences of Greggʼs Phenomenon
Circulation research, Vol.68(2), pp.482-492
02/1991
Handle:
https://hdl.handle.net/2376/106388
PMID: 1671343
Abstract
To assess the relation between increases in contractile function and oxygen consumption (Vo2) during increased coronary flow (Greggʼs phenomenon), we measured the end-systolic pressure-volume relation and the relation between Vo2 and left ventricular systolic pressure-volume area (PVA, a measure of total mechanical energy output) in blood-perfused, isovolumically contracting rabbit hearts during control and intracoronary adenosine infusion. During adenosine infusion at a constant perfusion pressure (93±11 mm Hg), coronary flow increased by 99±76% (p<0.01), and the slope of the end-systolic pressure-volume relation, Emax (ventricular contractility index), increased by 18±15% (p<0.01). When compared at the same left ventricular volume, PVA increased by 20±14% (p<0.01) and Vo2 by 19±15% (p<0.01) with adenosine. The Vo2-PVA relation was linear under each condition (both median r=0.98). With increased coronary flow, the Vo2-intercept of the Vo2-PVA relation (unloaded Vo2) increased by 22±18% (p<0.01) without a change in the slope; that is, a parallel upward shift was observed, indicating that the contractile efficiency (energy conversion efficiency of the contractile machinery) remained constant. These increases in Emax and unloaded Vo2 were not eliminated by β-adrenergic blockade with propranolol. We conclude that increased coronary flow with adenosine at a constant perfusion pressure augments both Emax and the nonmechanical energetic cost for excitation-contraction coupling and basal metabolism via nonadrenergic mechanisms, without changing contractile efficiency. (Circulation Research 1991;68:482–492)
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Details
- Title
- Effect of Coronary Hyperemia on Emax and Oxygen Consumption in Blood-Perfused Rabbit Hearts: Energetic Consequences of Greggʼs Phenomenon
- Creators
- Yoichi Goto - From the Department of Cardiovascular Dynamics, National Cardiovascular Center, Suita, Japan, and the Cardiology Unit, Department of Medicine, University of Vermont, Burlington, VtBryan SlinkerMartin LeWinter
- Publication Details
- Circulation research, Vol.68(2), pp.482-492
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Publisher
- American Heart Association, Inc
- Identifiers
- 99900547144801842
- Language
- English
- Resource Type
- Journal article