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Mizuno J, Matsubara H, Mohri S, Shimizu J, Suzuki S, Mikane T, Araki J, Hanaoka K, Akins R, Morita S. Half-logistic time constant: a more reliable lusitropic index than monoexponential time constant regardless of temperature in canine left ventricle. Can J Physiol Pharmacol 2008; 86:78-87. [DOI: 10.1139/y08-001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Temperature changes influence cardiac diastolic function. The monoexponential time constant (tauE), which is a conventional lusitropic index of the rate of left ventricular (LV) pressure fall, increases with cooling and decreases with warming. We have proposed that a half-logistic time constant (tauL) is a better lusitropic index than tauE at normothermia. In the present study, we investigated whether tauL can remain a superior measure as temperature varies. The isovolumic relaxation LV pressure curves from the minimum of the first time derivative of LV pressure (dP/dtmin) to the LV end-diastolic pressure were analyzed at 30, 33, 36, 38, and 40 °C in excised, cross-circulated canine hearts. tauL and tauE were evaluated by curve-fitting using the least squares method and applying the half-logistic equation, P(t) = PA/[1 + exp(t/tauL)] + PB, and the monoexponential equation, P(t) = P0exp(–t/tauE) + P∞. Both tauL and tauE increased significantly with decreasing temperature and decreased with increasing temperature. The half-logistic correlation coefficient (r) values were significantly higher than the monoexponential r values at the 5 above-mentioned temperatures. This implies that the superiority of the goodness of the half-logistic fit is not temperature dependent. The half-logistic model characterizes the amplitude and time course of LV pressure fall more reliably than the monoexponential model. Hence, we concluded that tauL is a more useful lusitropic index regardless of temperature.
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Affiliation(s)
- Ju Mizuno
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Hiromi Matsubara
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Satoshi Mohri
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Juichiro Shimizu
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Shunsuke Suzuki
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Takeshi Mikane
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Junichi Araki
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Kazuo Hanaoka
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Robert Akins
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
| | - Shigeho Morita
- Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
- Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
- Molecular Cardiology Laboratory, Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
- Department of Anesthesiology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
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