Quantitative Assessment of Fluid Accumulation Using Bioelectrical Impedance Analysis in Patients With Acute Decompensated Heart Failure.

Background: Acute decompensated heart failure (ADHF) is generally considered to be a problem of fluid volume overload, therefore accurately quantifying the degree of fluid accumulation is of critical importance in assessing whether adequate decongestion has been achieved. The aim of this study was to develop and validate a method to quantify the degree of fluid accumulation in patients with ADHF.

Methods and results: Using multi-frequency bioelectrical impedance analysis (BIA), we measured extracellular water (ECW) volume in 130 ADHF patients on admission and at discharge. We also predicted optimal ECW volume using original equations based on data from 60 control subjects without the signs of HF. Measured/predicted (M/P) ratio of ECW in ADHF patients was observed to decrease from 1.26±0.25 to 1.04±0.17 during hospitalization (P<0.001). The amount of ECW volume reduction was significantly correlated with reduction in body weight (r=0.766, P<0.001). On multivariate analysis, higher M/P ratio of ECW at discharge was associated with increased risk of ADHF readmission or cardiac death within 6 months after discharge.

Conclusions: Multi-frequency BIA-measured ECW was found to offer valuable information for analyzing the pathophysiology of ADHF, and may be a useful guide in the management of this disease.