Cardiac cooling increases Emax without affecting relation between O2 consumption and systolic pressure-volume area in dog left ventricle. 1988

H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
Department of Cardiovascular Dynamics, National Cardiovascular Center, Osaka, Japan.

We studied the effects of cardiac cooling by 7 +/- 2 degrees C (SD) from 36 degrees C on both contractility index (Emax) and the relation between O2 consumption per beat (VO2) and systolic pressure-volume area (PVA) of the left ventricle in the excised cross-circulated dog heart preparation. PVA represents the total mechanical energy generated by a contraction. The VO2-PVA relation divides measured VO2 into unloaded VO2 and excess VO2. The slope of the VO2-PVA relation represents inversely the efficiency of the contractile machinery to convert chemical energy from the excess VO2 to total mechanical energy. Cooling is known to decrease myosin ATPase activity (Q10 of 2-3), which in turn is expected to increase the chemomechanical efficiency of cross bridges. Therefore, we expected an increase in the efficiency and hence a decreased slope of the VO2-PVA relation with cooling. The cooling increased Emax by 46 +/- 13% and the time to Emax by 45 +/- 27%. Pacing rate was constant or had to be slightly decreased to avoid arrhythmias with cooling. We found that neither the slope of the VO2-PVA relation nor unloaded VO2 significantly (p greater than 0.05) changed with the cooling. This result contradicts the expected increase in the efficiency with cooling. We conclude that cardiac cooling by 7 degrees C from 36 degrees C does not increase the efficiency of the contractile machinery in excised cross-circulated dog left ventricle.

UI MeSH Term Description Entries
D009200 Myocardial Contraction Contractile activity of the MYOCARDIUM. Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
D010101 Oxygen Consumption The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346) Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D002306 Cardiac Volume The volume of the HEART, usually relating to the volume of BLOOD contained within it at various periods of the cardiac cycle. The amount of blood ejected from a ventricle at each beat is STROKE VOLUME. Heart Volume,Cardiac Volumes,Heart Volumes,Volume, Cardiac,Volume, Heart,Volumes, Cardiac,Volumes, Heart
D003080 Cold Temperature An absence of warmth or heat or a temperature notably below an accustomed norm. Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D006321 Heart The hollow, muscular organ that maintains the circulation of the blood. Hearts
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013599 Systole Period of contraction of the HEART, especially of the HEART VENTRICLES. Systolic Time Interval,Interval, Systolic Time,Intervals, Systolic Time,Systoles,Systolic Time Intervals,Time Interval, Systolic,Time Intervals, Systolic
D013696 Temperature The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms. Temperatures
D016276 Ventricular Function The hemodynamic and electrophysiological action of the HEART VENTRICLES. Function, Ventricular,Functions, Ventricular,Ventricular Functions

Related Publications

H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
August 1988, The American journal of physiology,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
June 1998, The Japanese journal of physiology,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
January 1989, Heart and vessels,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
November 1989, Circulation research,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
November 1979, The American journal of physiology,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
February 1994, Circulation,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
January 1981, The American journal of physiology,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
August 1988, Circulation research,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
January 1988, Advances in experimental medicine and biology,
H Suga, and Y Goto, and Y Igarashi, and Y Yasumura, and T Nozawa, and S Futaki, and N Tanaka
January 1976, Archives internationales de physiologie et de biochimie,
Copied contents to your clipboard!