title: Temperature-dependent inotropic and lusitropic indices based on half-logistic time constants for four segmental phases in isovolumic left ventricular pressure-time curve in excised, cross-circulated canine heart.
abstract: Varying temperature affects cardiac systolic and diastolic function and the left ventricular (LV) pressure-time curve (PTC) waveform that includes information about LV inotropism and lusitropism. Our proposed half-logistic (h-L) time constants obtained by fitting using h-L functions for four segmental phases (Phases I-IV) in the isovolumic LV PTC are more useful indices for estimating LV inotropism and lusitropism during contraction and relaxation periods than the mono-exponential (m-E) time constants at normal temperature. In this study, we investigated whether the superiority of the goodness of h-L fits remained even at hypothermia and hyperthermia. Phases I-IV in the isovolumic LV PTCs in eight excised, cross-circulated canine hearts at 33, 36, and 38 °C were analyzed using h-L and m-E functions and the least-squares method. The h-L and m-E time constants for Phases I-IV significantly shortened with increasing temperature. Curve fitting using h-L functions was significantly better than that using m-E functions for Phases I-IV at all temperatures. Therefore, the superiority of the goodness of h-L fit vs. m-E fit remained at all temperatures. As LV inotropic and lusitropic indices, temperature-dependent h-L time constants could be more useful than m-E time constants for Phases I-IV.
authors.affiliation: a Department of Anesthesiology and Pain Medicine, Juntendo University Faculty of Medicine, Tokyo 113-8431, Japan.|b Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8558, Japan.|c Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, Fukuoka, 812-8582, Japan.|d Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan.|e Department of Anesthesiology and Pain Relief Center, JR Tokyo General Hospital, Tokyo, 151-8528, Japan.
authors.forename: Ju
authors.initials: J
authors.lastname: Mizuno
authors.affiliation: b Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8558, Japan.|f First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mohri
authors.affiliation: c Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, Fukuoka, 812-8582, Japan.|d Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: d Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan.
authors.forename: Mikiya
authors.initials: M
authors.lastname: Otsuji
authors.affiliation: e Department of Anesthesiology and Pain Relief Center, JR Tokyo General Hospital, Tokyo, 151-8528, Japan.
authors.forename: Hideko
authors.initials: H
authors.lastname: Arita
authors.affiliation: e Department of Anesthesiology and Pain Relief Center, JR Tokyo General Hospital, Tokyo, 151-8528, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D000818:Animals; D003427:Cross Circulation; D004285:Dogs; D005334:Fever / Q000503:physiopathology*; D006321:Heart / Q000502:physiology*; D007035:Hypothermia / Q000503:physiopathology*; D016015:Logistic Models; D009200:Myocardial Contraction / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: constante de temps mono-exponentielle; hyperthermia; hyperthermie; hypothermia; hypothermie; inotropism; inotropisme; lusitropism; lusitropisme; mono-exponential time constant