Prognostic value of early and late spontaneous conversion into a shockable rhythm for patients with out-of-hospital cardiac arrest

Meng-Feng Tsai; Shao-Hua Yu; Ji-Syuan Sie; Fen-Wei Huang; Hong-Mo Shih

doi:10.1016/j.ajem.2022.09.025

Prognostic value of early and late spontaneous conversion into a shockable rhythm for patients with out-of-hospital cardiac arrest

Am J Emerg Med. 2022 Nov:61:192-198. doi: 10.1016/j.ajem.2022.09.025. Epub 2022 Sep 23.

Authors

Meng-Feng Tsai¹, Shao-Hua Yu², Ji-Syuan Sie³, Fen-Wei Huang³, Hong-Mo Shih⁴

Affiliations

¹ School of Medicine, College of Medicine, China Medical University, Taiwan; Department of Emergency Medicine, China Medical University Hospital, Taichung, Taiwan.
² School of Medicine, College of Medicine, China Medical University, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.
³ School of Medicine, College of Medicine, China Medical University, Taiwan.
⁴ School of Medicine, College of Medicine, China Medical University, Taiwan; Department of Emergency Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Public Health, China Medical University, Taichung, Taiwan. Electronic address: homoe042002@hotmail.com.

PMID: 36179648
DOI: 10.1016/j.ajem.2022.09.025

Abstract

Background: The prognostic significance of conversion into a shockable rhythm in patients who experienced out-of-hospital cardiac arrest (OHCA) with an initially nonshockable rhythm is controversial, perhaps due to the timing of rhythm conversion not being considered previously. We aimed to compare the different prognoses of patients with OHCA and early and late conversion of their rhythm into a shockable rhythm.

Methods: This was a single-centre retrospective cohort study. We enrolled patients with OHCA who were sent to a medical centre in central Taiwan from 2016 to 2020. Patients <18 years old, those with cardiac arrest due to trauma or a circumstantial cause, and those for whom resuscitation was not attempted were excluded. Patients were divided into two groups in accordance with presentation with an initially shockable rhythm. Those with an initially nonshockable rhythm were divided into three subgroups: early-conversion, late-conversion, and nonconversion groups. The primary outcome was the neurological functional status upon discharge from hospital.

Results: A total of 1645 patients with OHCA were included: initially shockable rhythm group, 339; early conversion group, 68; late-conversion group, 166; and nonconversion group, 1072. After adjustment, multivariate logistic regression revealed that a favourable neurological outcome was more common in the early conversion group than the nonconversion group (odds ratio [OR] 2.4; 95% confidence interval [CI], 1.1-5.3; p = 0.035), whereas the late-conversion group did not significantly differ from the nonconversion group (OR 0.5; 95% CI, 0.1-1.5; p = 0.211). The proportions of sustained return of spontaneous circulation and survival to discharge were also higher in the early conversion group than the late-conversion group (OR 2.9 95% CI 1.6-5.5, p = 0.001 and OR 4.5, 1.8-11.0, p = 0.001, respectively).

Conclusion: In patients who experience OHCA and have an initially nonshockable rhythm, early conversion into a shockable rhythm resulted in a better prognosis, whereas late conversion was not significantly different from nonconversion.

Keywords: Favourable neurological outcome; Out-of-hospital cardiac arrest; Rhythm conversion; Shockable rhythm.

MeSH terms

Adolescent
Cardiopulmonary Resuscitation* / methods
Electric Countershock / methods
Emergency Medical Services* / methods
Humans
Out-of-Hospital Cardiac Arrest*
Prognosis
Registries
Retrospective Studies