Outcomes of hospitalizations for heart failure with reduced ejection fraction complicated by cardiac arrest, stratified by pre-existing implantable cardioverter-defibrillator status

Abstract

Background: Hospitalizations for heart failure with reduced ejection fraction complicated by cardiac arrest represent a high-risk population, and the role of a pre-existing implantable cardioverter-defibrillator in these patients remains unclear.

Methods: We conducted a retrospective observational study using the National Inpatient Sample from 2016 through 2022. Adult hospitalizations (age 18 years or older) with heart failure with reduced ejection fraction and cardiac arrest were identified using diagnosis codes. Pre-existing defibrillator status was defined by a code indicating a device present before admission. Outcomes were compared by device status using survey-weighted methods, and a multivariable logistic regression model evaluated the independent association between device status and in-hospital mortality, adjusting for demographics, comorbidities, and clinical severity.

Results: Among 11,945 weighted hospitalizations, 545 (4.6%) had a documented pre-existing defibrillator. Crude in-hospital mortality was higher among hospitalizations with a device than those without (21.1% vs 9.7%, P<0.01). After adjustment, device status was not independently associated with in-hospital mortality (adjusted odds ratio 1.34, 95% confidence interval 0.63 to 2.84). Do-not-resuscitate status (adjusted odds ratio 15.56) and cardiogenic shock (adjusted odds ratio 1.47) were strongly associated with higher mortality.

Conclusions: In this national sample, pre-existing defibrillators were uncommon. Although crude mortality was higher among patients with a device, device status was not independently associated with in-hospital mortality after adjustment, suggesting outcomes were driven primarily by baseline risk and clinical severity. Studies incorporating arrest rhythm, timing, and device interrogation are needed to clarify mechanisms and optimize post-arrest management.