Résumé
Objective: End systolic left ventricular (LV) elastance (Ees) has been previouslycalculated and validated invasively using LV pressure-volume (P-V) loop. Noninvasive studies have been proposed, but clinical application remains complex.The aim of the present study was to 1) estimate Ees according to modeling ofLV P-V curve during ejection (“Ejection PV Curve’’ method) and validate ourmethod with existing published LV P-V loop data; 2) test clinical applicability todetect non invasively a difference in Ees between normotensive and hypertensivesubjects.Design and method: Based on P-V curve and a linear relationship between LV elastanceand time during ejection, we used a non linear least square method to fi t the systolicpressure curve. We then computed slope and intercept of time varying elastance,and calculated Ees as LV elastance at the end of ejection. As a validation, 22 P-V loopsobtained from previous invasive studies were digitized and analyzed with our method.To test clinical applicability, P-V curve was obtained from 33 hypertensive and 32normotensive subjects, using carotid tonometry and real time 3D echocardiography.Results: A good univariate relationship (r2 = 0.92, p < 0.005) and a good limit ofagreement were found between previous invasive calculation of Ees and our newproposed “Ejection P-V Curve’’ method. In addition, the clinical reproductibilityof our method was similar to that of another non invasive method proposed byChen et al. In hypertensive patients, the increase in arterial elastance (Ea) wascompensated by an increase in Ees without change in Ea/Ees (see Figure).Conclusions: Ees can be estimated non invasively from modeling of P-V curve duringejection. This approach was found to be reproducible and sensitive enough to detect anexpected difference in LV contractility in hypertensive patients. Due to its non invasivenature, this methodology may have clinical implications in various disease states.