Acute cardiac care & resuscitationCohort study
Association between preexisting electrocardiographic abnormalities and shockable initial rhythm in out-of-hospital cardiac arrest
- Registry-based study
- logistic regression
- stratified by witness status
Authors' conclusion
Among bystander-witnessed arrests, pathological Q-waves, left ventricular hypertrophy, atrial fibrillation, intraventricular conduction delay and left bundle branch block on the most recent hospital-recorded ECG within 30-365 days before OHCA were associated with higher odds of a shockable initial rhythm compared with individuals with normal ECGs.
Study context
- Population
- Individuals experiencing a first OHCA between 2016 and 2021, Danish Cardiac Arrest Registry, linked to the most recent hospital-recorded electrocardiographic (ECG) obtained 30–365 days prior to arrestindividuals experiencing a first OHCA, 11,167 (49.6%) bystander-witnessed, of whom 4,321 (38.7%) had a preceding ECG
- Participants
- 22,516 individuals
- Exposure
- ECG abnormalities preceding OHCA vs normal ECGs
Main finding
As reported in the abstract
Shockable initial rhythm, bystander-witnessed arrests
Each group vs normal ECGsOdds ratio (95% CI)
≥1 abnormality
1.44(1.10–1.90)
without a prior ECG
1.65(1.28–2.16)
Observational data: associations, not effects.
Further findings
| Outcome | Values | OR (95% CI) | |
|---|---|---|---|
| Shockable initial rhythm by specific abnormality, bystander-witnessed arrests — pathological Q-waves vs normal ECGs | pathological Q-waves 31.5% · left ventricular hypertrophy 27.0% · atrial fibrillation 33.9% · intraventricular conduction delay 42.8% · left bundle branch block 39.7% | 1.40 (1.16–1.69) | |
| Shockable initial rhythm by specific abnormality, bystander-witnessed arrests — left ventricular hypertrophy vs normal ECGs | 1.47 (1.14–1.89) | ||
| Shockable initial rhythm by specific abnormality, bystander-witnessed arrests — atrial fibrillation vs normal ECGs | 1.70 (1.38–2.10) | ||
| Shockable initial rhythm by specific abnormality, bystander-witnessed arrests — intraventricular conduction delay vs normal ECGs | 1.85 (1.38–2.46) | ||
| Shockable initial rhythm by specific abnormality, bystander-witnessed arrests — left bundle branch block vs normal ECGs | 2.03 (1.49–2.77) | ||
| 0.20.5125Odds ratio (log scale) |
Shockable initial rhythm, unwitnessed arrests
- Prevalence of a shockable initial rhythm was lower and associations were less consistent
Original publication
Association between preexisting electrocardiographic abnormalities and shockable initial rhythm in out-of-hospital cardiac arrest. Resuscitation. Published 27 July 2026. doi:10.1016/j.resuscitation.2026.111227
Summarised from the published abstract; every number is checked against it