Phase plane analysis of left ventricular hemodynamics

We sought to extract additional physiological information from the time-dep endent left ventricular (LV) pressure contour and thereby gain new insights into ventricular function. We used phase plane analysis to characterize hi gh-fidelity pressure data in selected subjects undergoing elective cardiac catheterization. The standard hemodynamic indexes of LV systolic and diasto lic function derived from the time-dependent LV pressure contour could be e asily obtained using the phase plane method. Additional novel attributes of the phase plane pressure loop, such as phase plane pressure loop area, gra phical representation of the isovolumic relaxation time constant, and quant itative measures of beat-to-beat systolic-diastolic coupling were character ized. The asymmetry between the pressures at which maximum isovolumic press ure rise and pressure fall occur, as well as their load dependence, were al so easily quantitated. These results indicate that the phase plane method p rovides a novel window for physiological discovery and has theoretical and applied advantages in quantitative ventricular function characterization.