Acute cardiac care & resuscitationCohort study
Does transthoracic impedance influence termination and recurrence of ventricular fibrillation during impedance-compensated shocks for out-of-hospital cardiac arrest? A retrospective study
- retrospective observational study
- mixed-effects logistic regression models applied to shock level data with a random intercept for clustering by patient
Authors' conclusion
Despite impedance-compensated defibrillation, TTI ≥100 Ω remains associated with reduced likelihood of VF/pVT termination in OHCA. In contrast, TTI does not appear to influence the risk of recurrent VF/pVT following successful termination.
Study context
- Population
- Non-traumatic OHCA in patients aged ≥16 years with an initial shockable rhythm, January 2019 to October 2022cases, 8333 analysable shocks
- Participants
- 1,880 participants
- Exposure
- The relationship between TTI and VF/pVT termination and recurrence
Main finding
As reported in the abstract
VF/pVT termination (unadjusted)
- The unadjusted probability of VF/pVT termination declined at TTI values ≥100 Ω, whereas no clear relationship was observed at TTI <100 Ω
Observational data: associations, not effects.
Further findings
VF/pVT termination (adjusted)
| Comparison | adjusted OR per 1-Ω increase (95% CI) | P value | |
|---|---|---|---|
| TTI <100 Ω · not associated | 0.999 (0.993–1.006) | P = 0.860 | |
| TTI ≥100 Ω · lower odds of termination | 0.994 (0.988–0.999) | P = 0.016 | |
| 0.512Adjusted or per 1-ω increase (log scale) |
Recurrent VF/pVT, among shocks that resulted in VF/pVT termination
| Comparison | adjusted OR per 1-Ω increase (95% CI) | P value | |
|---|---|---|---|
| TTI · not associated | 1.003 (0.999–1.006) | P = 0.082 | |
| 0.512Adjusted or per 1-ω increase (log scale) |
Original publication
Does transthoracic impedance influence termination and recurrence of ventricular fibrillation during impedance-compensated shocks for out-of-hospital cardiac arrest? A retrospective study. Resuscitation. Published 25 May 2026. doi:10.1016/j.resuscitation.2026.111151
Summarised from the published abstract; every number is checked against it