Effect of hypertonicity on contractility of isolated working rat left ventricle

• Published in: Cardiovascular research 1992-04, Vol.26 (4), p.379-382
• Main Authors: Ben-Haim, Shlomo A, Hayam, Gal, Edoute, Yeouda, Better, Ori S
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; cardiac mechanics; contractility; Emergency and intensive care: techniques, logistics; Hypertonic Solutions - pharmacology; Intensive care medicine; Male; Mannitol - pharmacology; Medical sciences; Myocardial Contraction - drug effects; Organ Culture Techniques; osmolality; Osmolar Concentration; Perfusion; Perfusions. Catheterizations. Hyperbaric oxygenotherapy; Rats; Rats, Inbred Strains; Ventricular Function, Left - drug effects
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1093/cvr/26.4.379

Objective: The aim was to evaluate the effect of hypertonic perfusate on isolated left ventricular mechanical and energetic characteristics. Methods: An isolated working rat heart model was perfused with a hyponatraemic Krebs-Heinseleit bicarbonate buffer (240 mOsmol·litre−1). To this buffer was added increasing amounts of mannitol to achieve 280, 320, and 360 mOsmol·litre−1 perfusates. Results: Left ventricular peak pressure, maximum time derivative of left ventricular pressure (dP/dtmax), and end systolic pressure were all increased to a maximum value at 280 or 320 mOsmol·litre−1 perfusate tonicity. A similar response was evident with cardiac output, which changed from 33.7(SEM 0.6) to 43.5(0.8) ml·min−1 following changing the perfusate tonicity from 240 to 280 mOsmol·litre−1 (p≤0.003). However, increasing perfusate tonicity further decreased cardiac output to 36.5(1.3) ml·min−1 at 360 mOsmol·litre−1. Maximal left ventricular elastance remained unchanged during perfusion with increasing perfusate tonicities. Conclusions: Changing perfusate osmolality using mannitol has a positive inotropic effect at low osmolalities and a negative inotropic effect at perfusate osmolality greater than 320 mOsm·litre−1.