January 1, 1996Circulation
Undetected Ventricular Fibrillation in Transvenous Implantable Cardioverter-Defibrillators
Key result
Standard bipolar sensing in transvenous ICDs was associated with significantly less ventricular fibrillation undersensing after failed shocks compared to integrated bipolar sensing (3% vs 20%, P<0.01).
Why the study?
Does standard bipolar sensing improve the redetection of ventricular fibrillation after unsuccessful shock compared to integrated bipolar sensing in patients with transvenous ICDs?
Population
361 patients with transvenous implantable cardioverter-defibrillators, including 160 with standard bipolar…
Comparison
Standard bipolar sensing in transvenous ICDs vs Integrated bipolar sensing in transvenous ICDs
Design
Cohort
Follow-up
up to 12 months
Authors
Discussion
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Implication
May support preferring standard bipolar sensing in transvenous ICDs to reduce post-shock VF undersensing; leaves open need for randomized confirmation.
Key Points
- This study analyzes how different implantable cardioverter-defibrillator (ICD) systems detect ventricular fibrillation (VF) after failed shocks.
- Prospective analysis of 160 ICDs with standard bipolar and 201 with integrated bipolar sensing.
- Delivery of intentional subthreshold shocks to assess redetection characteristics of VF at various time points.
- Electrogram analysis to understand detection failures and their association with device settings.
- Standard bipolar sensing shows 3% undersensing vs. 20% in integrated systems, P<.01.
- Redetection time is longer for the CPI system compared to Ventritex, P<.05.
- No deaths occurred in patients with VF undersensing during follow-up.
Study Design
Type
Observational (n=361)
Structured PICO
Does standard bipolar sensing improve the redetection of ventricular fibrillation after unsuccessful shock compared to integrated bipolar sensing in patients with transvenous ICDs?
P
Population
361 patients with transvenous implantable cardioverter-defibrillators followed for up to 12 months to assess ventricular fibrillation redetection after subthreshold shocks.
E
Exposure
Standard bipolar sensing in transvenous ICDs
C
Comparator
Integrated bipolar sensing in transvenous ICDs
O
Outcome
Redetection of ventricular fibrillation (VF) after unsuccessful subthreshold shocksafety
Main Result
Absolute Event Rate: 3% vs 20%
p-value: p=<.01
Standard bipolar sensing in transvenous ICDs is more effective at redetecting ventricular fibrillation after a failed shock compared to integrated bipolar sensing.
Limitations
- The clinical relevance of this phenomenon remains unknown.
Cite This Study
Natale et al. (1996) conducted an observational in Transvenous implantable cardioverter-defibrillators (n=361). Standard bipolar sensing vs. Integrated bipolar sensing was evaluated on Undersensing of ventricular fibrillation after failed shocks (p=<.01). Standard bipolar sensing in transvenous ICDs was associated with significantly less ventricular fibrillation undersensing after failed shocks compared to integrated bipolar sensing (3% vs 20%, P<0.01).