Echocardiographic automated border detection (ABD) provides an instantaneous measurement of left ventricular (LV) volume and its rate of change. We tested the clinical feasibility of ABD in monitoring on-line LV response to acute changes in preload. We examined 20 healthy males in the supine position, with legs elevated, back in the supine position, 5 min after the inflation of blood pressure cuffs at the root of the four limbs, 5 min after the deflation of cuffs. End-diastolic and end-systolic LV volumes significantly increased with elevated legs and decreased during cuff inflation; ejection fraction remained unchanged. Peak filling and peak emptying rates did not change with elevated legs and increased significantly during cuff inflation. The values of LV parameters were stable in the three resting conditions, demonstrating a good reproducibility of the ABD technique. Our results demonstrate that ABD may be useful in clinical practice for monitoring on-line small acute changes in LV volume and function.