Change in Intrathoracic Impedance Measures During Acute Decompensated Heart Failure Admission: Results From the Diagnostic Data for Discharge in Heart Failure Patients (3D-HF) Pilot Study

BackgroundDespite the high number of admissions for acute decompensated heart failure (ADHF), there are no specific criteria for discharge readiness. A number of patients have implantable devices that might provide data to assist in determining readiness for discharge.Methods and ResultsThe 3D-HF (Diagnostic Data for Discharge in Heart Failure Patients) study was a prospective observational pilot study enrolling HF patients with Optivol-capable cardiac devices within 48 hours of a hospital admission characterized by worsening HF symptoms. The primary end point was the difference in times from admission to 50% improvement in impedance and to when patient was medically ready for discharge. The nonparametric sign test was used to determine if the difference was significant. A total of 20 subjects were enrolled over a 24-month period. The median ADHF length of stay was 7 days. Of the 20 subjects, 18 achieved the intrathoracic impedance improvement threshold before discharge. The time to reach the threshold for improvement was 2.5 days (interquartile range 2.0–6.0). The difference between days to 50% impedance and days to provider’s discharge decision was 3.0 (P = .0072).ConclusionsIntrathoracic impedance changes were evident over a short duration in the majority of patients admitted for ADHF and may be a potential criterion for discharge readiness.