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Bystander cardiopulmonary resuscitation and cardiac rhythm change over time in patients with out-of-hospital cardiac arrest
  1. Keita Shibahashi,
  2. Taichi Kato,
  3. Mayu Hikone,
  4. Kazuhiro Sugiyama
  1. Tertiary Emergency Medical Center, Metropolitan Bokutoh Hospital, Sumida-ku, Japan
  1. Correspondence to Dr Keita Shibahashi, Tertiary Emergy Medical Center, Metropolitan Bokutoh Hospital, Sumida-ku, 130-8575, Japan; kshibahashi{at}


Background Whether and how bystander cardiopulmonary resuscitation (CPR) modifies the cardiac rhythm after out-of-hospital cardiac arrest (OHCA) over time remains unclear. We investigated the association between bystander CPR and the likelihood of ventricular fibrillation (VF) or ventricular tachycardia (VT) as the first documented cardiac rhythm.

Methods We identified individuals with witnessed OHCA of cardiac origin from a nationwide population-based OHCA registry in Japan between 1 January 2005 and 31 December 2019. The first documented cardiac rhythm was compared between patients who received bystander CPR and those who did not, using a 1:2 propensity score-matched analysis.

Results Of 309 900 patients with witnessed OHCA of cardiac origin, 71 887 (23.2%) received bystander CPR. Propensity score matching paired 71 882 patients who received bystander CPR with 143 764 who did not. The likelihood of detecting a VF/VT rhythm was significantly higher among patients who received bystander CPR than among those who did not (OR 1.66; 95% CI 1.63 to 1.69; p<0.001). Comparing the two groups at each time point, the difference in the proportions of patients with VF/VT rhythms peaked at 15–20 min but was insignificant at 30 min postcollapse (15 min after collapse; 20.9% vs 13.9%; p<0.001). The likelihood of a pulseless electrical activity rhythm was significantly lower in patients who received bystander CPR during the first 25 min postcollapse (15 min after collapse; 26.2% vs 31.5%; p<0.001). The two groups had no significant difference in the likelihood of asystole (15 min after collapse; 51.0% vs 53.3%; p=0.078).

Conclusion Bystander CPR was associated with a higher VF/VT likelihood and a lower likelihood of pulseless electrical activity at first documented rhythm analysis. Our results support early CPR for OHCA and highlight the need for further research to understand whether and how CPR modifies the cardiac rhythm after arrest.

  • chain of survival
  • first responders
  • resuscitation

Data availability statement

No data are available. Not applicable.

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  • Handling editor Edward Carlton

  • Contributors KSh: conceptualisation, methodology, formal analysis, writing—original draft preparation, guarantor. TK, MH and KSu: methodology, writing—reviewing and editing.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.