ISSN:
1435-1803
Keywords:
oxygen consumption
;
internal work
;
external work
;
source resistance
;
afterload impedance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The relationship between myocardial oxygen consumption ( $$M\dot VO_2 $$ ) and left ventricular work was examined experimentally, assuming that the left ventricle is equivalent to an electrical current source generator consisting of parallel source resistance (Ri) and constant generator current (I0). The internal and external work can be calculated as (Ri×I1 2) and (Rp×I2 2) in this model, where I1 is current of source resistance, Rp is peripheral resistance and I2 is cardiac output. The experiments were performed with a blood-perfused isolated ejecting canine heart preparation in which the hydraulic model, simulated to an aortic input impedance, was attached to the aortic root. The peripheral resistance was changed in a stepwise fashion and left ventricular pressure, cardiac output and $$M\dot VO_2 $$ were measured. The calculated total work showed a close linear correlation with the $$M\dot VO_2 $$ which suggested that the left ventricle can be regarded as a current source generator and the total work as a main mechanical factor in determining the $$M\dot VO_2 $$ .
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01908037
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