Abstract 15829: Temporal Characteristics of Intra-thoracic Impedance Before and After Heart Failure Hospitalizations in a Large Real-world Population of Patients With Cardiovascular Implanted Electronic Devices

Abstract

Introduction: Intrathoracic impedance (IMP), measured in ICD/CRTD implantable devices, is a measure of intravascular blood volume and have been shown to correlate with intracardiac pressures. We investigated the temporal characteristics of IMP before and after HF events (HFE) in a large real-world cohort of patients (pts) with ICD/CRTD devices. Methods: We linked Optum© deidentified EHR dataset during the period from 2007-2017 to the Medtronic CareLink data warehouse. Pts with ICD/CRTD implants with IMP measurements were included. HFE was defined as an inpatient, ED, or observation unit stay with primary diagnosis of HF and IV diuretics administration. Temporal average of IMP measurement across all pts in the 60 days pre and post HFE were compared for HFE with and without readmission for HF within 60 days and in pts with no HFE. Results: A total of 17,886 pts with 1.8±1.2 years of follow-up met inclusion criteria. The average age was 66.6 ±12.3 years, with 72% being males, and 51% with ICD devices. A total of 1174 pts had 1425 HFE with no readmission and 282 pts had 295 HFE which were followed by readmission. A total of 17,839 pts had no HFE over 86,858 follow-up months. The average IMP during HFE, with and without readmission, and in pts with no HFE are shown in Fig. IMP decreases over a period of time prior to HFE and recovers due to treatment during HFE. The average IMP across all patients was lower on all 60 days pre and post HFE with readmission compared to HFE with no readmission (p<0.001) and both were lower compared to follow-up period with no HFE (p<0.001). The IMP recovers less often after HF events which are followed by readmission within 60 days compared to HF events with no readmission. Conclusions: In a large real-world population of pts with ICD/CRTD devices, on an average IMP reduces prior to and recovers during HFE. IMP was lower before and after HFE with readmission compared to HFE with no readmission. Readmission is more likely in pts with smaller impedance recovery after HF events.