The accuracy of functional curves generated by ultrasound Automated Boundaries Detection (ABD) with reference to time-volumes (-activity) curves obtained by standard non-invasive technique is not completely studied. Therefore we performed both echocardiography with ABD and gated blood pool ventriculography (GBPV) in 22 patients (mean age 53, range 18 ± 73 yrs) suffering from dilated cardiomyopathy (8 pts), ischemic (7) and valvular (2) cardiopathy and cardiomyoplasty (4). Using apical 2 and 4 Chamber views with gains optimized to detect the most continuous ABD and maximal cavity size, EF (Simpson rule), peak empting rate (PER) and peak filling rate (PFR) were automatical displayed and tape recorded. Both end diastolic area (EDA) and volumes (EDV) were considered for PER and PFR calculation and 6 to 10 consecutive beats were averaged. GBPV images were acqUired in the LAO best septal projection, on a 64 × 64 pixels matrix. The two examinations were performed within 15 minutes. ABD EF ranged from 11 to 65%. Correlations of ABD vs GBP LV function measurement were: ABD r SEE Intercept p < 0.0001 EF 2–Ch 0.98 2.4 1.8 ” EF 4–Ch 0.97 3.1 4.9 ” PER/EDA 2-Ch 0.95 0.22 0.3 ” PER/EDV 2-Ch 0.96 0.22 0.25 ” PER/EDA 4-Ch 0.92 0.22 0.65 ” PFR/EDA 2-Ch 0.94 0.25 0.01 ” PFR/EDV 2-Ch 0.78 0.36 0.7 ” PFR/EDA 4-Ch 0.94 0.22 0.25 ” These preliminary results indicate that on-line time-areas and volume curves generated by ABD display are comparable to time-activity curves derived by GBPV. Geometric assumption can explain the best performance of ABD in PER and PFR estimation using fractional area changes. The absence of radiation exposure and the real time display of ABD are potential advantages of ultrasound systems in non-invasive assessment of LV function.