Heart Rate as a Predictor of Mortality in Heart Failure Patients at the Time of Discharge from the Intensive Care Unit

ObjectiveHeart rate serves as a critical prognostic factor in heart failure patients. We hypothesize that elevated heart rate in critically ill heart failure patients upon discharge from the intensive care unit (ICU) could be linked to adverse outcomes. DesignWe implemented a retrospective cohort study using data collected between 2008 and 2019 from the Medical Information Mart for Intensive Care IV (MIMIC-IV version 2.0) database. We examined the association between the last heart rate prior to ICU discharge and in-hospital mortality, total mortality, and ICU readmission. SettingICU at Beth Israel Deaconess Medical Center PatientsAdult patients admitted to the ICU diagnosed with heart failure. InterventionsNone Measurements and Main ResultsFrom the 76,943 ICU stays, we enrolled 2,365 patients in this study. We observed correlations between in-hospital mortality and ICU discharge heart rate of 83.56{+/-}15.81 bpm (survivors) vs. 93.84{+/-}17.28 bpm (nonsurvivors, p<0.001). Total mortality showed similar trends, with 83.67{+/-}15.36 bpm (survivors) vs. 85.23{+/-}17.25 bpm (nonsurvivors, p=0.027), as did ICU readmissions at 83.55{+/-}15.77 bpm (nonreadmitted) vs. 88.64{+/-}17.49 bpm (readmitted, p<0.001). Given multivariate analysis, the ICU discharge heart rate strongly predicted in-hospital mortality (OR 1.035 [95% CI 1.024-1.046], p < 0.001), total mortality (OR 1.007 [95% CI 1.001-1.014], p = 0.027) and ICU readmission (OR 1.015 [95% CI 1.007-1.023], p < 0.001). Patients with an ICU discharge heart rate >90 bpm demonstrated significantly higher in-hospital mortality (OR 2.986 [95% CI 2.066-4.315], p < 0.001), total mortality (OR 1.341 [95% CI 1.083-1.661], p = 0.007), and ICU readmission rates (OR 1.638 [95% CI 1.270-2.114], p < 0.001). ConclusionsThe findings suggest that heart failure patients with an elevated heart rate (>90 bpm) at ICU discharge are more likely to experience increased in-hospital mortality, total mortality, and ICU readmissions, indicating potential negative outcomes. Key PointsQuestion: Does an elevated heart rate at ICU discharge increase in-hospital mortality, total mortality, and ICU readmission? Findings: This retrospective cohort study using the Medical Information Mart for Intensive Care IV database showed that a higher ICU discharge heart rate >90 bpm is a strong predictor of increased in-hospital mortality (OR 2.986, p < 0.001), total mortality (OR 1.341, p = 0.007), and ICU readmission (OR 1.638, p < 0.001). Meaning: Heart failure patients with an elevated heart rate (>90bpm) at ICU discharge are more likely to face increased risks of in-hospital mortality, total mortality, and ICU readmissions.