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DIVERGENT CHANGES IN THE RATE OF DEVELOPMENT OF PRESSURE IN THE LEFT VENTRICLE AND IN THE PERFORMANCE OF THE HEART AS A PUMP
Author(s) -
Kane Kathleen A.,
Ungar A.
Publication year - 1976
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1976.sp002332
Subject(s) - preload , ventricle , cardiology , medicine , inotrope , heart rate , stroke volume , afterload , ventricular pressure , aortic pressure , blood pressure , hemodynamics , anesthesia
Dog hearts were prepared in situ so that heart rate (HR), left ventricular end diastolic pressure (LVEDP) and mean aortic pressure (MAP) could be controlled separately during computation of left ventricular d P /dt max and external stroke work (sw). Progressive increases in HR consistently raised d P /dt max over a wide range, and consistently lowered sw except at low rates. Progressive increases in LVEDP or MAP consistently raised both d P /dt max and sw. Infusion of noradrenaline consistently raised both d P /dt max and sw, except at very high HR when only d P /dt max was consistently raised. Our results lead us to question the validity of equating changes in pre‐ejection measurements with changes in performance of the heart as a pump under abnormal conditions and in the assessment of inotropic agents.