Histologic and biochemical correlates of left ventricular chamber dynamics in man

To investigate the relation between left ventricular chamber dynamics in humans and the quantitative analysis of the histologic and biochemical characteristics of left ventricular endomyocardial biopsy material, 15 patients with a wide range of ventricular function were studied. The pressure-volume relation was determined using simultaneous gated radionuclide angiography, echocardiography and micromanometer pressure. The derived chamber dynamics were then compared with quantitative histologic data (percent fibrosis and cell diameter) and adenosine triphosphate content measurements obtained from the left ventricular biopsy specimen obtained at the time of the pressure-volume studies. The measures of systolic function correlated linearly with high energy phosphate content. The adenosine triphosphate/protein ratio (nanomoles) was shown to parallel ejection fraction (r = 0.81), peak ejection rate (r = −0.73) and peak positive maximal rate of rise in left ventricular pressure (dP/dt) (r = 0.79). No correlation was observed between these variables and the percent fibrosis or cell diameter. Variable results were found in comparing the diastolic properties of the left ventricle with the biopsy data. In general, the high energy phosphate content correlated with measures of active relaxation, but not with the passive filling characteristics of the left ventricle. The adenosine triphosphate/protein ratio was linearly related to peak negative dP/dt (r = −0.74) and the peak filling rate (r = 0.76) but correlated less well with other measures of active and passive diastolic filling. No correlation was found between any diastolic variable and the percent fibrosis or cell diameter. Thus, this study suggests that a fundamental relation can be observed in humans between the high energy phosphate content of the left ventricular endomyocardial biopsy specimen and certain systolic and early diastolic chamber dynamics.