Key result
Defibrillating shocks of 300 V (5.9 J) were significantly less effective when delivered after 15 seconds of ventricular fibrillation compared with 5 seconds (45% vs 82%, p<0.01).
Why the study?
Does a longer duration of ventricular fibrillation (15 seconds vs 5 seconds) reduce defibrillation efficacy in patients undergoing AICD implantation?
Population
22 patients undergoing automatic implantable cardioverter-defibrillator implantation or generator change
Comparison
Defibrillating shocks ranging from 300 to 600 V… vs Defibrillating shocks ranging from 300 to 600 V…
Design
Other
Follow-up
Immediate (postshock)
Authors
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Shorter VF-to-shock intervals may boost defibrillation success; leaves open optimal timing strategies in clinical resuscitation.
Does a longer duration of ventricular fibrillation (15 seconds vs 5 seconds) reduce defibrillation efficacy in patients undergoing AICD implantation?
Absolute Event Rate: 45% vs 82%
p-value: p=<0.01
Longer durations of ventricular fibrillation significantly reduce defibrillation efficacy at lower energies and cause greater postshock hemodynamic depression, which has implications for defibrillation threshold testing and device programming.
Winkle et al. (1990) studied Ventricular fibrillation (n=22). Defibrillating shocks after 15 seconds of ventricular fibrillation vs. Defibrillating shocks after 5 seconds of ventricular fibrillation was evaluated on Defibrillation efficacy for 300-V (5.9 J) shocks (p=<0.01). Defibrillating shocks of 300 V (5.9 J) were significantly less effective when delivered after 15 seconds of ventricular fibrillation compared with 5 seconds (45% vs 82%, p<0.01).
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