PMID: 42965Feb 1, 1979

Cardiac performance: optimal heart rate for maximal cardiac output

Scandinavian Journal of Clinical and Laboratory Investigation
A IlebekkF Kiil

Abstract

To determine optimal heart rate for the maximal cardiac output at various levels of inotropy and blood volume, the relationship between heart rate (HR) and stroke volume (SV) was examined in anaesthetized dogs during right atrial pacing. Myocardial inotropy was raised by intravenous infusion of isoproterenol, a stimulator of adrenergic beta-receptors, and reduced by propranolol, an inhibitor of adrenergic beta-receptors. Circulating blood volume was increased by saline infusion. Within the range of optimal heart rate, SV and HR were inversely related: SV = k (HR0-HR), where k indicates the relationship between changes in SV and HR. The intercept with the HR axis is HR0. At constant HR a rise in inotropy increased SV and a fall in inotropy reduced SV. These changes in SV were eual at every HR, and k was therefore constant. In contrast, blood volume expansion increased SV more at low than at high HR (k increased), but HR0 was not significantly changed. Calculated maximal cardiac output: k.HR02/4, and optimal heart/rate: HR0/2, agreed with observations when maximal cardiac output was raised from 1900 to 4500 ml/min by increasing blood volume and inotropy. Optimal HR was not influenced by changes in blood volume, but was increased ...Continue Reading

References

Sep 1, 1971·The American Journal of Cardiology·A W Cowley, A C Guyton
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Citations

Apr 14, 2004·American Journal of Veterinary Research·Francisco J Teixeira NetoSumit Duronghphongtorn
Nov 1, 1986·Pacing and Clinical Electrophysiology : PACE·T NappholtzT Simmons
Aug 1, 1985·Clinical Physics and Physiological Measurement : an Official Journal of the Hospital Physicists' Association, Deutsche Gesellschaft Für Medizinische Physik and the European Federation of Organisations for Medical Physics·T J van der WerffR J Douglas

Related Concepts

Adrenergic beta-Agonists
Adrenergic beta-Antagonists
Cardiac Output
Cardiac Pacing, Artificial
Canis familiaris
Pulse Rate
Novodrin
Myocardial Contraction
Rexigen
Sodium Chloride, (24)NaCl

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