Determination of Kinetic Energy of the Heart in Man

Prec, O.; Katz, Louis N.; Sennett, Leslie; Rosenman, R. H.; Fishman, Alfred P.; Hwang, Wonjun

doi:10.1152/ajplegacy.1949.159.3.483

Cited by 48 publications

(33 citation statements)

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“…In the present study, an estimation of stroke work was obtained using noninvasively measured blood pressure with a sphygmomanometer and stethoscope, and diastolic pressure was hard to accurately determine during exercise. Interestingly, even with these limitations, the modeled KE values, expressed as percent of total external cardiac work during rest, are similar to the values obtained using in vivo pressure quantifications (31).…”

Section: Limitationssupporting

confidence: 71%

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Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements

Carlsson

Heiberg

Töger

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

123

146

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Carlsson M, Heiberg E, Toger J, Arheden H. Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements. Am J Physiol Heart Circ Physiol 302: H893-H900, 2012. First published December 16, 2011; doi:10.1152/ajpheart.00942.2011.-We aimed to quantify kinetic energy (KE) during the entire cardiac cycle of the left ventricle (LV) and right ventricle (RV) using four-dimensional phasecontrast magnetic resonance imaging (MRI). KE was quantified in healthy volunteers (n ϭ 9) using an in-house developed software. Mean KE through the cardiac cycle of the LV and the RV were highly correlated (r 2 ϭ 0.96). Mean KE was related to end-diastolic volume (r 2 ϭ 0.66 for LV and r 2 ϭ 0.74 for RV), end-systolic volume (r 2 ϭ 0.59 and 0.68), and stroke volume (r 2 ϭ 0.55 and 0.60), but not to ejection fraction (r 2 Ͻ 0.01, P ϭ not significant for both). Three KE peaks were found in both ventricles, in systole, early diastole, and late diastole. In systole, peak KE in the LV was lower (4.9 Ϯ 0.4 mJ, P ϭ 0.004) compared with the RV (7.5 Ϯ 0.8 mJ). In contrast, KE during early diastole was higher in the LV (6.0 Ϯ 0.6 mJ, P ϭ 0.004) compared with the RV (3.6 Ϯ 0.4 mJ). The late diastolic peaks were smaller than the systolic and early diastolic peaks (1.3 Ϯ 0.2 and 1.2 Ϯ 0.2 mJ). Modeling estimated the proportion of KE to total external work, which comprised ϳ0.3% of LV external work and 3% of RV energy at rest and 3 vs. 24% during peak exercise. The higher early diastolic KE in the LV indicates that LV filling is more dependent on ventricular suction compared with the RV. RV early diastolic filling, on the other hand, may be caused to a higher degree of the return of the atrioventricular plane toward the base of the heart. The difference in ventricular geometry with a longer outflow tract in the RV compared with the LV explains the higher systolic KE in the RV.four-dimensional phase-contrast magnetic resonance imaging; cardiovascular magnetic resonance; energy; cardiac function; heart failure CARDIAC PUMPING DELIVERS A pressurized blood volume to the systemic and the pulmonary circulation. The amount of external work required to deliver the volume and pressure can be divided into kinetic energy (KE) and stroke work. Total work of the heart also includes internal work not delivered to the system. Stroke work stands for the vast majority (99%) of the external energy at rest in the left ventricle (LV) (29, 31) and somewhat less in the right ventricle (RV, 94%) (31). The structure of the looped heart has been proposed to direct the momentum or KE of the inflowing blood toward the aorta (18), which may be of specific importance during exercise (17). The magnitude and significance of maintenance of KE of blood in the looped heart has recently been under debate (16, 39 -40). KE is linked to inertia, an important physiological concept (37,41). Inertia is a physical concept describing the maintenance of the forward velocity of a medium (e.g., blood) after a force has...

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Section: Limitationssupporting

confidence: 71%

“…To estimate mean pulmonary pressure, we assumed that this was onesixth of the mean arterial pressure on the left ventricular side (31).…”

Section: Energy and Power During Rest And Exercisementioning

confidence: 99%

Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements

Carlsson

Heiberg

Töger

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

123

146

View full text Add to dashboard Cite

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“…8 ' 12 In the present experiments, such calculations would underestimate the pressure power in the pulCtrcuUtum Rtsurcb, Vol. XIX, Stpumin 1966 monary artery by 10%, on the average, with individual variations ranging from -21 to +10%.…”

Section: Scontrasting

confidence: 52%

Hydraulic Power Associated with Pulmonary Blood Flow and its Relation to Heart Rate

Milnor

Bergel

Bargainer

1966

Circulation Research

184

133

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Pulmonary vascular input impedance and hydraulic power were measured at various heart rates in 29 anesthetized and 5 unanesthetized dogs. Hydraulic power at the pulmonary veno-atrial junction was measured in 5 dogs. The pulmonary vascular impedance spectrum in the unanesthetized dogs did not differ significantly from that in the anesthetized dogs. Average pulmonary arterial power in the anesthetized dogs was 157 milliwatts (mw), of which 108 mw was associated with mean pressure and flow, and 49 mw with the pulsations around these means. Seventy-eight per cent of this input power was dissipated in passage through the pulmonary bed. Kinetic energy accounted for 1% of the total input power.Because of a steep fall in impedance between zero and 3 cycles/sec, and a rate-dependent change in the harmonic structure of flow pulsations, there was an inverse relationship between heart rate and the input power for a given mean flow, up to 180 beats/ min. Pulmonary vascular dimensions and elasticity, which determine impedance, thus embody a mechanism whereby tachycardia can increase pulmonary blood flow by as much as 35% with an increase in pulmonary arterial input power of less than 5%, without the intervention of vasomotor activity.

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“…Reported values for the systemic bed have been given as 0.25 to 2% (5,16). The pulmonary bed is much higher, 7 to 10% (3, 4), but decreases with pulmonary hypertension (17).…”

Section: Figure 10mentioning

confidence: 99%

Fourier Analysis of Left Ventricular Performance

Abel

1971

Circulation Research

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Fourier analysis has been applied to simultaneously obtained ventricular pressure, ascending aortic pressure, and aortic flow in the closed-and openchest dog and during infusion with isoproterenol, norepinephrine, and phenylephrine. Partial measurements were also obtained from a sheep and a primate. Impedance moduli and phases were calculated from the ventricular (forcing) and aortic (input) side of the aortic valve and compared. Forcing impedance was similar in form but larger than input impedance, and the phase became positive earlier. Ventricular and aortic powers were calculated and expressed as pressure power, kinetic energy power, and reactive power, along with their harmonic distributions. Mean pressure represented 80 to 91% of total load power but only 20 to 51% of total ventricular power. Calculated efficiency varied from 35% with isoproterenol infusion to 100% with norepinephrine, phenylephrine, and open-chest states. Control efficiency was 78%. The concept of impedance matching was investigated; maximal efficiency occurred with optimal matching. Internal resistance was shown to represent an easily measurable quantity which also partially corresponds to the more complex impedance measurement.KEY WORDS ventricular impedance phenylephrine isoproterenol internal resistance ventricular power norepinephrine ventricular efficiency thoracotomy kinetic energy• Numerous reports have used Fourier series and spectral analysis to describe the complex input impedances of the systemic and pulmonary circuits and the hydraulic power consumed (1-6). The generators providing the inputs into these beds (the right and left ventricles) have largely been ignored in these descriptions, yet their characteristics would appear to be equally important in terms of their ability to match the impedance of the vascular bed supplied for maximum efficiency and power transfer, for purposes of modeling of the cardiovascular system and the design of artificial hearts, and perhaps as another way of describing ventricular performance.Abel (7) and Fronek (8) have previously described an "internal impedance" for the left ventricle using only mean flow and pressure measurements, thereby lumping all the properties that vary with frequency as a "resistance" value. It is feasible, however, to describe the forcing impedance of the ventricle and the hydraulic power produced in the same manner as that used for the input impedances and power consumption of the systemic and pulmonary beds. This report deals with such a concept and with the ability of the pump to match its associated bed in terms of impedance and power transfer at

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Determination of Kinetic Energy of the Heart in Man

Cited by 48 publications

References 0 publications

Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements

Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements

Hydraulic Power Associated with Pulmonary Blood Flow and its Relation to Heart Rate

Fourier Analysis of Left Ventricular Performance

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