Are Pressure-Volume Relations at End-Systole a Reflection of Left Ventricular Myocardial Contractility?

Abstract

The pressure-volume relation at end-systole is reportedly altered by changes in contractility. To explore the potential of this ratio in man 185 subjects including 23 normals (Group I) were studied. In 35 patients of Group II (16 with mitral stenosis, 7 with atrial septal defect, and 12 with cor pulmonale) ESP/ESV like an index of contractility measuring force-velocity-length rela tionship (Cy Ix) was insignificantly different from Group I (ESP/ESV and Cy Ix in I = 1.73 ± .31 mmHg/sec, 1.46 ± .09 cm/sec/cm vs 1.44 ± .10, 1.31 ± .05 in II respectively.) With significantly reduced Cy Ix (1.03 ± .04, P<0.00001) ESP/ ESV was likewise reduced (1.16 ± .07, P<0.007) in 108 patients with compen sated LV disease (34 with alcoholic cardiomyopathy, 16 coronary artery dis ease, 30 aortic valve disease, 8 hypertension and 16 with other heart muscle disease.) Like the Cy Ix (0.70 ± .05, P<0.001) ESP/ESV was even lower (0.84 ± .13, P<0.05) in 14 patients with decompensated LV (Group IV). It was insensitive to changes in pressure (angiotensin and volume (dextran). However unlike the Cy Ix it did not vary with acute changes in inotropy (exercise and pacing).

The correlations between ESP/ESV and ejection fraction and contractility index in the entire series though weak, were significant (r = .50 and .20 respectively, each P<0.006). Exclusion of patients with aortic valve disease and hypertension in the analysis tended to improve the relationship between the contractility and end-systolic pressure-volume parameters. In the latter two subgroups neither the ESV nor the ESP/ESV ratio related to the contractil ity index, both parameters however did correlate significantly with the ejection fraction. These results indicate that end-systolic pressure-volume relations provide useful measures of LV performance in man, though not expressing the contractility either in all patients or under all situations.

Get full access to this article

View all access options for this article.

References

Siegel JH , Sonnenblick EH : Isometric time-tension relationships as an index of myocardial contractility . Circ Res 12:597-610, 1963.

Frank MJ , Levinson GE : An index of the contractile state of the myocardium in man. J Clin Invest 47:1615-1626, 1968.

Falsetti HL , Mates RD , Green DG , Bunnell IL : Vmax as an index of contractile state in man. Circ 43:467-479, 1971.

Karliner JS , Peterson KL , Ross J. Jr: Myocardial mechanics: Assessment of isovolumic and ejection phase indices of left ventricular performance. In: Cardiac Catheterization and Angiocardiography, ed. by Grossman W , Philadelphia, Lea and Febiger, 1974 , pp. 188-206.

Vanden Bos GC , Elzinga G. , Westerhoff N. , Nobel MI : Problems in the use of indices of myocardial contractility. Cardiovascular Research 7:834-848, 1973.

Pollack GH : Maximum velocity as an index of contractility in cardiac muscle. Circ Res 26:111-117, 1970.

Suga H. , Sagawa K. : Instantaneous pressure-volume relationships and their ratio in the excised, supported canine left ventricle. Circ Res 35:117-126, 1974.

Sagawa K. , Suga H. , Shoukas AA , Kakalar KM : End-systolic pressure-volume ratio: A new index of ventricular contractility . Am J Cardiol 40:748-753, 1977.

Grossman W. , Braunwald E. , Mann T. , et al: Contractile state of the left ventricle in man as evaluated from end-systolic pressure-volume relations. Circ 56:845-852, 1978.

10.

Nivatpumin T. Katz S. , Scheuer J. : Peak left ventricular systolic pressure-end-systolic volume ratio: A sensitive detector of left ventricular disease. Am J Cardiol 43:969-974, 1979.

11.

Mitchell JH , Wildenthal K. , Mullins CB : Geometrical studies of the left ventricle utilizing biplane cinefluorography. Federation Proceedings 28:1334-1343, 1969.

12.

Ahmed SS , Regan TJ , Fiore JJ , Levinson GE : The state of the left ventricular myocardium in mitral stenosis. Am Heart J 94:28-36, 1977.

13.

Frank MJ , Weisse AB , Moschos CB , Levinson GE : Left ventricular function metabolism and blood flow in cor pulmonale. Circ 47:798-806, 1973.

14.

Haider B. , Ahmed SS , Moschos CB , et al: Myocardial function and coronary blood flow response to acute ischemia in chronic canine diabetes. Circ Res 40:577-583, 1977.

15.

Knopp TJ , Rahimtoola SG , Swan Hjc : First derivative of ventricular pressure recorded by means of conventional cardiac catheters. Cardiovasc Res 4:398-404, 1970.

16.

Kinsman JM , Moore HA , Hamilton WF : Studies on the circulation I: Injection method: Physical and mathematical consideration. Am J Physiol 89:322-330, 1929.

17.

Frank MJ , Nadimi M. , Hilmi KI , Levinson GE : Measurement of mitral regurgitation in man by the upstream sampling method using continuous indicator infusion. Circ 35:100-111, 1967.

18.

Levinson GE , Frank MJ , Nadimi M. , Braunstein M. : Studies of cardiopulmonary blood volume: Measurement of left ventricular volume by dye dilution. Circ 35:1038-1048, 1967.

19.

Hugenholtz PG , Wagner HR , Sandler H. : In vivo determination of left ventricular volume: Comparison of the fiberoptic-indicator dilution and the angiocardiographic methods. Circ 37:489-508, 1968.

20.

Mullins CB , Leshin SJ , Mierzwiak DS , et al: Changes in left ventricular function produced by the injection of contrast media. Am Heart J 83:373-381, 1972.

21.

Popio KA , Ross AM , Oravec JM , Ingram JT : Identification and description of separate mechanisms for two components of renografin cardiotoxicity. Circ 58:520-528, 1978.

22.

Caulfield JB , Zir L. , Harthorne JW : Blood calcium levels in the presence of arteriographic contrast material. Circ 52:119-123, 1975.

23.

Brown AK , Epstein EJ , Coulshed N. , et al: Hemodynamic changes after angiocardiography. Brit Heart J 31:233-245, 1969,

24.

Carleton RA , Bowyer AF , Graettinger JS : Overestimation of left ventricular volume by the indicator dilution technique. Circ Res 18:248-256, 1966.

25.

Frank MJ , Cundey PE Jr, Crews TL , Lewis WJ III: Comparison of left ventricular volumes by single-plane cineangiography and by indicator dilution. J Lab Clin Med 77:580-593, 1971.

26.

Swan H. , Ganz V. , Wallace JC , Tamura K. : Left ventricular end-diastolic volume (EDV) by angiographic and thermal methods of a single diastole. Circ 38:VI-193, 1968 (abstract).

27.

Swan Hjc , Beck W. : Ventricular nonmixing as a source of error in the estimation of ventricular volume by the indicator dilution technique. Circ Res 8:989-998, 1960.

28.

Levine HJ , Brittman NA : Force-velocity relations in the intact dog heart. J Clin Invest 43:1383-1396, 1964.

29.

Quinones MA , Gasch WH , Alexander JK : Influence of acute changes in preload, afterload, contractile state and heart rate on ejection and isovolumic indices of myocardial contractility in man. Circ 53:293-301, 1976.

30.

Ross J. Jr, Braunwald E. : The study of left ventricular function in man by increasing resistance to ventricular ejection with angiotensin. Circ 29:739-749, 1964.

31.

Bowditch HP : Uber die eigenthumlichkieten der reizbarkeit, welchedie muskalfasern des herzen ziegen. Arbeit Physiol Anstalt Leipzig 6:652-689, 1871.

32.

Leighton RF , Zaron SJ , Robinson JL , Weissler AM : Effects of atrial pacing on left ventricular performance in patients with heart disease. Circ 60:615-622, 1969.