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Energetics of the Heart

  • Hiroyuki Suga
  • Shiho Futaki
  • Yoichi Goto

Summary

A new measure of the total mechanical energy (TME) generated by ventricular contraction was proposed to be quantified by a specific area in the pressure-volume (P-V) diagram that is bounded by the end-systolic and end-diastolic P-V relations and the systolic P-V trajectory. This area is called the systolic P-V area (PVA), interchangeably used with TME. We found in the left ventricle of the excised, cross-circulated dog heart preparation that PVA correlated linearly with myocardial O2 consumption (\( {V_{{o_2}}} \)) regardless of loading conditions in a stable contractile state. The load-independent linear \( {V_{{o_2}}} \)-PVA relation was elevated in a parallel manner by positive inotropic interventions, primarily due to an increased \( {V_{{o_2}}} \)for the augmented excitation-contraction coupling. The slope of the \( {V_{{o_2}}} \)-PVA relation can be considered to reflect inversely the efficiency of energy conversion to PVA from the excess \( {V_{{o_2}}} \)above unloaded \( {V_{{o_2}}} \). This efficiency is primarily the product of the oxidative phosphorylation efficiency from \( {V_{{o_2}}} \)to ATP and the contractile machinery efficiency from ATP to PVA. Thus, the \( {V_{{o_2}}} \)PVA relation seems a promising tool for the anlayses of cardiac energetics and mechanoenergetic coupling.

Keywords

Contractile State Total Energy Input Cardiac Mechanic Contractile Machinery Total Mechanical Energy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Gibbs CL (1978) Cardiac energetics. Physiol Rev 58: 174–254PubMedGoogle Scholar
  2. 2.
    Braunwald E, Ross J, Sonnenblick EH (1976) Mechanisms of contraction of the normal and failing heart, 2nd edn. Little Brown, Boston, pp 166–199Google Scholar
  3. 3.
    Suga H, Hayashi T, Shirahata M (1981) Ventricular systolic pressure-volume area as predictor of cardiac oxygen consumption. Am J Physiol 240: H39–H44PubMedGoogle Scholar
  4. 4.
    Suga H, Hisano R, Goto Y, Yamada O, Igarashi Y (1983) Effect of positive inotropic agents on the relation between oxygen consumption and systolic pressure-volume area in canine left ventricle. Circ Res 53: 306–318PubMedGoogle Scholar
  5. 5.
    Hisano R, Cooper G (1987) Correlation of force-length area with oxygen consumption in ferret papillary muscle. Circ Res 61: 318–328PubMedGoogle Scholar
  6. 6.
    Goto Y, Slinker BK, LeWinter MM (1988) Similar normalized Emax and O2 consumption-pressure volume area relation in rabbit and dog. Am J Physiol 255: H366–H374PubMedGoogle Scholar
  7. 7.
    Suga H (1979) Total mechanical energy of a ventricular model and cardiac oxygen consumption. Am J Physiol 236: H498–H505PubMedGoogle Scholar
  8. 8.
    Suga H (1980) Relaxing ventricle performs more external work than quickly released elastic energy. Eur Heart J 1(Suppl A): 131–137Google Scholar
  9. 9.
    Suga H, Sagawa K, Shoukas AA (1973) Load independence of the instantaneous pressure-volume ratio of the canine left ventricle and effects of epinephrine and heart rate on the ratio. Circ Res 32: 314–322PubMedGoogle Scholar
  10. 10.
    Suga H, Hayashi T, Suehiro S, Hisano R, Shirahata M, Ninomiya I (1981) Equal oxygen consumption rates of isovolumic and ejecting contractions with equal systolic pressure-volume area in canine left ventricle. Circ Res 49: 1082–1091PubMedGoogle Scholar
  11. 11.
    Suga H, Goto Y, Nozawa T, Yasumura Y, Futaki S, Tanaka N (1987) Force-time integral decreases with ejection despite constant oxygen consumption and pressure-volume area in dog left ventricle. Circ Res 60: 797–803PubMedGoogle Scholar
  12. 12.
    Suga H, Goto Y, Yamada O, Igarashi Y (1984) Independence of myocardial oxygen consumption from pressure-volume trajectory during diastole in canine left ventricle. Circ Res 55: 734–739PubMedGoogle Scholar
  13. 13.
    Yasumura Y, Nozawa T, Futaki S, Tanaka N, Suga H (1989) Time-invariant oxygen cost of mechanical energy in dog left ventricle: Consistency and inconsistency of time-varying elastance model with myocardial energetics. Circ Res 64: 764–778PubMedGoogle Scholar
  14. 14.
    Suga H, Goto Y, Yasumura Y, Nozawa T, Futaki S, Tanaka N, Uenishi M (1988) O2 consumption of dog heart under decreased coronary perfusion and propranolol. Am J Physiol 254: H292–H303PubMedGoogle Scholar
  15. 15.
    Suga H, Igarashi Y, Yamada O, Goto Y (1985) Mechanical efficiency of the left ventricle as a function of preload, afterload and contractility. Heart Vessels 1: 3–8PubMedCrossRefGoogle Scholar
  16. 16.
    Suga H, Goto Y, Igarashi Y, Yasumura Y, Nozawa T, Futaki S, Tanaka N (1988) Cardiac cooling increases Emax without affecting relation between O2 consumption and systolic pressure-volume area in dog left ventricle. Circ Res 63: 61–71PubMedGoogle Scholar
  17. 17.
    Alpert NR, Mulieri LA (1986) Determinants of energy utilization in the activated myocardium. Fed Proc 45: 2697–2600Google Scholar
  18. 18.
    Gibbs CL, Chapman JB (1985) Cardiac mechanics and energetics: chemomechanical transduction in cardiac muscle. Am J Physiol 249: H199–H206PubMedGoogle Scholar
  19. 19.
    Gibbs CL (1987) Cardiac mechanics and the Fenn effect. Basic Res Cardiol 82 (Suppl 2): 61–68PubMedGoogle Scholar
  20. 20.
    Yasumura Y, Suga H (1988) Crossbridge model compatible with the linear relation between left ventricular oxygen consumption and pressure-volume area. Jpn Heart J 29: 335–347PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Tokyo 1989

Authors and Affiliations

  • Hiroyuki Suga
  • Shiho Futaki
  • Yoichi Goto
    • 1
  1. 1.Department of Cardiovascular DynamicsNational Cardiovascular Center Research InstituteOsakaJapan

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