Cardiac arrest & resuscitation
Association between preexisting electrocardiographic abnormalities and shockable initial rhythm in out-of-hospital cardiac arrest
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 with a first out-of-hospital cardiac arrest (OHCA) 2016–2021, Danish Cardiac Arrest Registry11,167 bystander-witnessed
- Participants
- 22,516 individuals
- Exposure
- Electrocardiographic (ECG) abnormalities vs normal ECG 30-365 days before OHCA
- Outcome
- Shockable initial rhythm
Methodological detailsnationwide registry, adjusted logistic regression, stratified by witness status
- Nationwide registry
- Adjusted logistic regression
- Stratified by witness status
Main finding
As reported in the abstract
Shockable initial rhythm, bystander-witnessed arrests
Each group vs normal ECGOdds ratio (95% CI)
≥1 abnormality
1.44(1.10–1.90)
No prior ECG
1.65(1.28–2.16)
Observational data: associations, not effects.
Further findings
| Outcome | Values |
|---|---|
| Shockable initial rhythm by specific ECG abnormality vs normal ECG, bystander-witnessed | Pathological Q-waves 31.5% · OR 1.40 (95% CI 1.16-1.69) · Left ventricular hypertrophy 27.0% · OR 1.47 (95% CI 1.14-1.89) · AF 33.9% · OR 1.70 (95% CI 1.38-2.10) · Intraventricular conduction delay 42.8% · OR 1.85 (95% CI 1.38-2.46) · Left bundle branch block 39.7% · OR 2.03 (95% CI 1.49-2.77) |
Shockable initial rhythm, unwitnessed arrests
- Lower prevalence of shockable initial rhythm and less consistent associations
Original publication
Association between preexisting electrocardiographic abnormalities and shockable initial rhythm in out-of-hospital cardiac arrest. Resuscitation. Published 27 July 2026. doi:10.
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