Differential recovery of device-derived physiologic parameters after heart-failure hospitalization: insights from 12,000 cardiac device events

Background Continuous diagnostics from cardiac implantable electronic devices (CIEDs) provide quantitative insights into physiologic recovery following heart failure (HF) hospitalization. Post-discharge trajectories of device-derived metrics may help identify patients at risk for recurrent decompensation. Purpose To characterize 30-day post-discharge changes in five device-derived parameters—activity, intrathoracic impedance, daytime heart rate (DHR), nighttime heart rate (NHR), and heart-rate variability (HRV)—and compare recovery profiles between patients with and without 60-day HF readmission. Methods We analyzed 12,369 HF hospitalization events from patients with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators, using data from the Medtronic CareLink™ database (2007–2021) linked to the Optum® de-identified Electronic Health Record dataset. Daily averages for each parameter were evaluated over 30 days post-discharge. For each patient, mean values and changes from the first post-discharge week to days 8–30 were compared between those readmitted within 60 days and those not readmitted. Results All five parameters showed significantly different recovery trajectories between readmitted and non-readmitted groups (p<0.001 for each). Patients who were not readmitted exhibited faster normalization of physiologic metrics, including higher average daily activity (85.1 vs. 74.5 min/day, p<0.05) and a more rapid increase in intrathoracic impedance (65.4 vs. 64.1, p<0.05), suggesting improved pulmonary fluid status. Conversely, patients readmitted within 60 days had persistently elevated daytime (78.1 vs. 76.6 bpm, p<0.05) and nighttime heart rates (75.0 vs. 73.0 bpm, p<0.05), as well as reduced heart-rate variability (39.1 vs. 41.5 ms, p<0.05). Figure 1 panels A–D illustrates daily changes in activity, NHR, and HRV following discharge. These patients demonstrated slower and less coordinated recovery across all parameters, indicating persistent autonomic imbalance and hemodynamic congestion during early convalescence. Conclusion Distinct physiologic recovery signatures captured by implanted device diagnostics can differentiate patients at risk for early HF readmission. High-risk trajectories are characterized by slower rises in impedance, reduced activity, elevated heart rates, and attenuated HRV. Continuous CIED-based surveillance may enable early identification of subclinical deterioration during post-discharge recovery.