Matching between feline left ventricle and arterial load: optimal external power or efficiency

Toorop, G. P.; Horn, G J van den; Elzinga, G.; Westerhof, Nico

doi:10.1152/ajpheart.1988.254.2.h279

Cited by 31 publications

(14 citation statements)

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“…Several theoretical models based on the mammalian left ventricle have suggested that the vascular and ventricular properties are matched to achieve maximal transfer of mechanical energy or maximal ventricular metabolic efficiency (Sunagawa et al, 1983;Burkhoff and Sagawa, 1986;Van den Horn et al, 1985;Toorop et al, 1988). De Tombe et al (1993) have suggested that, when confronted with variable vascular loading, these parameters are both kept nearly maximal, although not precisely optimised.…”

Section: Discussionmentioning

confidence: 99%

Effect of coronary perfusion on the basal performance, volume loading and oxygen consumption in the isolated resistance-headed heart of the troutOncorhynchus mykiss

Agnisola

Petersen²,

Mustafa³

2003

Journal of Experimental Biology

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SUMMARYBasal performance, volume loading response and oxygen consumption were determined in a resistance-headed preparation of the isolated trout heart. Two groups of hearts were used: the +CF group, in which the coronary vascular tree was perfused with a flow directly related to the pressure generated by the heart, and the -CF group, in which the coronary flow was set to zero. As a criterion for setting basal performance, the atrial input pressure was set in order to induce the ventricle to produce a cardiac output of 15 ml min-1 kg-1. Once basal conditions were obtained, the preparation was perfused for 30 min, and atrial and aortic pressure, cardiac output, heart rate, coronary pressure and coronary flow were determined at 5 min intervals. At the onset of perfusion, there was no difference in the basal performance between the two groups: the same preload was necessary to get the same cardiac output in both perfusion groups. None of the other performance parameters determined were different. However, after only 5 min of perfusion,the -CF hearts displayed significant adjustments, with increased atrial preload and ventricular preload (mean atrial pressure), and a significant decrease in cardiac output. At the end of the 30 min basal perfusion period,hearts were challenged with a stepwise increase in preload in order to obtain maximal stroke work (volume loading). The effect of coronary perfusion on the heart's response to volume loading was highly significant: the stroke work-preload relationship was significantly shifted towards higher preload values in the -CF group. Also, the maximal work produced by the heart under the experimental conditions used was lower in the -CF group. Rate of oxygen consumption of the heart increased significantly with volume loading, from a basal value of approximately 20 μl O2 min-1g-1 to approx. 40 μl O2 min-1g-1, but was not significantly affected by the absence of coronary perfusion. Mechanical efficiency under basal conditions was approximately 17%,but was not affected by either volume loading or coronary perfusion. Taken as a whole, these data represent direct evidence of the effect of coronary perfusion on the mechanical performance of the trout heart, but also show that these effects are limited by significant self-adjustments that occur in the heart.

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Section: Discussionmentioning

confidence: 99%

Effect of coronary perfusion on the basal performance, volume loading and oxygen consumption in the isolated resistance-headed heart of the troutOncorhynchus mykiss

Agnisola

Petersen²,

Mustafa³

2003

Journal of Experimental Biology

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“…Recently, several studies have provided evidence that the left ventricle and the arterial circulation interact in such a manner as to optimize cardiac energetics (28)(29)(30)(31)(32)(33)(34)(35)(36) Ee;S at any given EDV (35). In this study, the EJEfS ratio was near unity at baseline (0.91±0.53), suggesting that the ventricle and arterial properties were matched such that external stroke work was maximized; however, Ea/Ee, was not statistically different from 0.5.…”

Section: Discussionmentioning

confidence: 99%

Importance of mitral subvalvular apparatus in terms of cardiac energetics and systolic mechanics in the ejecting canine heart.

Yun

Niczyporuk²,

Sarris³

et al. 1991

J. Clin. Invest.

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“…They have shown in their experimental studies that the normal left ventricle is adapted to its arterial afterload to yield a maximum SW, when Ea/Emax equals unity. Elzinga and Westerhof [20], van den Horn et al [21], Toorop et al [22], and Piene and Sund [23] have also shown that, in excised hearts and in intact conscious animals, the normal left ventricle is adapted to its arterial afterload to yield maximum power. Our study was based on these experimental findings in previous studies.…”

Section: Influence Of Arterial-ventricular Coupling On the Sw-ved Relmentioning

confidence: 97%

Cardiodynamic conditions for the linearity of preload recruitable stroke work

et al. 1995

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Studies reported in the literature show that the stroke work (SW) versus end-diastolic volume (Ved) relationship, namely, the preload recruitable stroke work relation (PRSW), is experimentally linear in closed-chest dog hearts and its slope reflects left ventricular contractility. We considered the theoretical cardiodynamic conditions necessary for the linearity of the SW-Ved relation by utilizing ventricular end-systolic elastance, Emax (ventricular contractility), and effective arterial elastance, Ea (arterial afterload). We simulated the SW-Ved relation, using four theoretical models of the left ventricle, as follows: Ea is constant and the end-systolic pressure-volume relation (ESPVR) is linear (model 1), or nonlinear (model 2), and Ea is variable and ESPVR is linear (model 3), or nonlinear (model 4). The results show that the SW-Ved relation can be linear in both linear and nonlinear ESPVR models (models 3 and 4) only when Ea is variable. In these models, end-systolic pressure (Pes) and Ea should gradually fall, maintaining the stroke volume (SV) relatively constant with decreases in Ved until the low end of the physiological Ved range. Then, Ea should rise sharply so that Pes does not fall below the critical level. These results suggest that the autoregulation mechanisms of an intact animal operate to adapt the arterial afterload against acute changes in LV preload, maintaining cardiac output and coronary artery pressure. Such mechanisms may thus produce a linear SW-Ved relation over a wide range of conditions.

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Matching between feline left ventricle and arterial load: optimal external power or efficiency

Cited by 31 publications

References 0 publications

Effect of coronary perfusion on the basal performance, volume loading and oxygen consumption in the isolated resistance-headed heart of the troutOncorhynchus mykiss

Effect of coronary perfusion on the basal performance, volume loading and oxygen consumption in the isolated resistance-headed heart of the troutOncorhynchus mykiss

Importance of mitral subvalvular apparatus in terms of cardiac energetics and systolic mechanics in the ejecting canine heart.

Cardiodynamic conditions for the linearity of preload recruitable stroke work

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