785-2 Clinical Feasibility of Echocardiographic Automated Boundary Detection in Monitoring Left Ventricular Response to Acute Changes of Preload in Normal Subjects

Abstract

Automated Boundary Detection (ABD), recently incorporated into standard echocardiographic system, provides an on-line instantaneous measurement of left ventricular (LV) volume and its derivative as a function of time (dV/dt). The aim of our study was to test the clinical feasibility of ABD in monitoring acute LV changes. We evaluated the LV response to acute changes in preload in 15 normal males (mean age 32 ± 6 years), examined 5 times: in the supine position (A). with legs elevated 45° to 60° (B), back in the supine position (C), 5’ after the simultaneous inflation of blood pressure cuffs at the root of the 4 limbs (D) (pressure of the cuffs set at 10 mmHg below the basal diastolic pressure of each subject) and back in the supine position (E). Real time LV volumes by ABD were obtained in the 4 chamber view, with gains optimized to detect the most continuous ABD. We evaluated: systolic (SBP) and diastolic blood pressure (DB PI, heart rate (HR), LV end-diastolic (EDV) and end-systolic volume (ESV). ejection fraction (EF). normalized peak filling rate (PFR), defined as maximal positive dVldt, and normalized peak ejection rate (PER), defined as maximal negative dVldt, both standardized for EDV. A B C D E SBP (mmHg) 119 ± 12 122 ± 11 120 ± 10 117 ± 10 121 ± 11 DBPlmmHg) 77 ± 6 79 ± 6 76 ± 8 77 ± 5 78 ± 5 HR (bimini 66 ± 4 68 ± 6 65 ± 5 66 ± 5 67 ± 6 EDV(ml) 91 ± 22 102 ± 30 * 89 ± 20 75 ± 21 ** 87 ± 19 ESV(mll) 33 ± 10 43 ± 11 * 35 ± 13 26 ± 11 * 32 ± 9 EF % 61 ± 10 57 ± 9 60 ± 8 64 ± 10 59 ± 7 PFR (mllsec) 448 ± 0.7 4.49 ± 06 4.45 ± 0.7 5.03 ± 0.7 * 451 ± 08 PER (mllsec) 4.20 ± 0.5 4.00 ± 04 4 0.14 ± 0.5 4.77 ± 0.5 ** 4.23 ± 06 * p < 0.005; ** P < 0.001 Bvs A, D vs C Measurements in A, C and Ewere practically identical, thus demonstrating a good reproducibility of the ABD technique. Our results demonstrate that ABO can be used in clinical practice when acute changes in LV volume and its rate of change are to be monitored.