Introduction: An impairment of cardiac haemodynamics and fluid retention may occur in patients with acute heart failure (AHF) because of left ventricular (LV) dysfunction due to volume and or pressure overload. The measurement of B-type natriuretic peptide (BNP) represents the 'gold standard' of biomarker assessment for evaluating LV adaptations to AHF. More recently, Nexfin and bioelectric impedance vector analysis (BIVA) techniques have been proposed for non-invasively assessing haemodynamic and hydration status, respectively. These techniques are rapidly and easily executable and, most importantly, may be repeated over time. Aim: To validate the applicability of Nexfin and BIVA techniques, in association with BNP dosage, and changes of these parameters after treatment during hospitalization in patients with AHF referring to the emergency department (ED). Methods: We enrolled 44 patients (20 female, mean age 77 -7.7 years), referring to ED for AHF. During hospitalization (mean -SD: 4.12 -1.45 days), all patients underwent BNP measurements at admission, 24 hours, 72 hours and at discharge. At the same time intervals, Nexfin and BIVA were also performed. According to international guidelines, all patients were treated with optimal pharmacological therapy, independently of other parameters examined during hospitalization. Results: Compared with baseline (747.61 -658.54 pg mL), we observed a statistically significant reduction of BNP levels at 72 hours (357.64 -193.81 pg mL; p < 0.05) and at discharge times (248.57 -194.46 pg mL; p < 0.05). In addition, a significant reduction of hydration status, evaluated through BIVA, was observed at discharge compared with hospital admission (from 79.44 -6.47% to 76.35 -5.5%; p < 0.05). This was paralleled at Nexfin evaluation by a significant increase of cardiac index (from 2.32 -0.95 to 3.9 -1.18 L min m 2 ) and clinical improvement of New York Heart Association class at discharge compared with hospital admission. Finally, we observed a statistically significant correlation between percentage variation of cardiac index and hydration status from admission to discharge (p < 0.05). Conclusions: In patients with AHF, admitted to ED, simultaneous monitoring of cardiac index and of hydration status by non-invasive methods may be useful for confirming clinical diagnosis, beyond dosages of BNP. These techniques could also be useful for intra-hospital management of AHF patients. In fact, their variations, coupled with the BNP ones, during hospitalization, may be of value in order to easily and rapidly identify clinical and haemodynamic improvements of AHF, which may be of key relevance for appropriate discharges from EDs.