Association between pre-arrest left ventricular ejection fraction and survival in nontraumatic out-of-hospital cardiac arrest.

Background and importance: Out-of-hospital cardiac arrest (OHCA) poses major public health issues. Pre-arrest heart function is a prognostic factor, but the specific contribution of pre-arrest echocardiographic evaluation in predicting OHCA outcome remains limited.

Objective: The primary objective was to investigate the association between left ventricular ejection fraction (LVEF) measured in echocardiography prior to OHCA and survival to hospital discharge.

Design, settings, and participants: This multicenter retrospective cohort study analyzed data from the National Taiwan University Hospital and its affiliated hospitals. We included adult nontraumatic OHCA patients who were treated by the emergency medical services (EMS) and underwent echocardiography within 6 months prior to the OHCA event from January 2016 to December 2022. Data included demographics, preexisting diseases, resuscitation events, and echocardiographic reports.

Outcomes measure and analysis: The primary outcome was the survival to hospital discharge after post-arrest care. Statistical analysis involved multivariable logistic regression to modify potential confounders, reported as adjusted odds ratio (aOR) and 95% confidence interval (CI), and evaluate the association between echocardiographic findings and survival to hospital discharge.

Main results: This study analyzed 950 patients, with 33.6% surviving to discharge. A higher pre-arrest LVEF was independently associated with increased survival. Compared to patients with LVEF < 40%, those with LVEF between 40% and 60% had significantly higher odds of survival (aOR = 3.68, 95% CI = 2.14-6.35, P < 0.001), and those with LVEF > 60% had even greater odds of survival (aOR = 5.46, 95% CI = 3.09-9.66, P < 0.001). There was also an association between lower tricuspid regurgitation pressure gradient and survival (aOR = 0.98, 95% CI = 0.97-1.00, P = 0.015). Younger age, male gender, dyslipidemia, stroke, cancer, witnessed arrest, initial shockable rhythm, and shorter low-flow time are other significant predictors of survival.

Conclusion: In adult, nontraumatic, EMS-treated OHCA patients, a higher LVEF 6 months prior to OHCA was associated with improved survival at hospital discharge.