Figure 1
From: Non invasive evaluation of cardiomechanics in patients undergoing MitraClip procedure
Left ventricular end-systolic elastance was calculated by the single-beat method validated by Chen et al. [14]. The echo figures display the evaluation of ejection fraction (left panel) and pre-ejection and ejection time (right panel) using aortic Doppler waveform. Normalized ventricular elastance at arterial end-diastole (End) was measured according to the formula: E es(sb) = [P d - (E Nd(est) • P s • 0.9)]/[SV • E Nd(est)], E Nd(avg) = ∑ ai • t Nd i = 0, E Nd(est) = 0.0275 - 0.165 • EF + 0.3656 • (P d /P es ) + 0.515 • E Nd(avg) where ai are (0.35695, -7.2266, 74.249, -307.39, 684.54. -856.92, 571.95, -159.1) for i = 1 to 7, respectively. The value for tNd was determined by the ratio of pre-ejection period (R wave to flow onset) to total systolic period (R wave to end-flow), with the time of onset and termination of flow defined Doppler. Systolic (Ps) and diastolic (Pd) blood pressure were invasively obtained.