A new technique for the study of left ventricular pressure-volume relations in man.

Abstract

Study of left ventricular pressure-volume relations in man has been limited by technical problems associated with left ventricular angiography. A new approach to this problem using simultaneous recording of left ventricular pressure and left ventricular volume (determined by echocardiography) was applied in 21 patients. Pressure-volume plots, constructed from pressure and volume values sampled at 20 or 40 msec intervals, had characteristic shapes for the states studied: normal, pressure overload, volume overload, and myocardial disease. These curves closely resembled pressure-volume plots previously determined by others from quantitative angiography. The area inscribed by these plots was integrated to calculate left ventricular stroke work. Left ventricular stroke work index (gram-meters/m 2 ) was in the range previously reported for the various states; normal-41 ± 12, pressure overload-102 ± 14, volume overload-136 ± 36, myocardial disease-65 ± 19. Inspection of the pressure-volume plots allowed assessment of valvular regurgitation by the characteristic deformation of the loop during "isovolumic" contraction and relaxation. Study of diastolic filling allowed qualitative assessment of left ventricular compliance. Patients with pressure overload had stiffer ventricles, with high diastolic pressure at lower volume, than normal or volume overload patients. In summary, a new method is described for the beat-to-beat analysis of left ventricular pressure-volume relations in man.