July 25, 2008Pacing and Clinical Electrophysiology
Right Pectoral Implantable Cardioverter Defibrillators: Role of the Proximal (SVC) Coil
Key result
Activating the SVC coil in right pectoral ICDs is linked to ~35% lower impedance.
- P<0.0001
- n=42
Why the study?
Does turning the SVC coil On improve defibrillation thresholds and shock characteristics in patients with right pectoral ICDs?
Population
42 patients with right pectoral implantable cardioverter defibrillators undergoing defibrillation threshold…
Comparison
Proximal (SVC) coil On vs Proximal (SVC) coil Off
Design
Cohort
Authors
Discussion
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Implication
Activating the SVC coil may modify shock delivery in right pectoral ICDs; leaves open effects on defibrillation thresholds and warrants prospective study.
Study Design
Type
Observational (n=42)
Structured PICO
Does turning the SVC coil On improve defibrillation thresholds and shock characteristics in patients with right pectoral ICDs?
P
Population
42 patients (mean age 62, 38% female) with right pectoral implantable cardioverter defibrillators undergoing defibrillation threshold testing.
E
Exposure
Proximal (SVC) coil On
C
Comparator
Proximal (SVC) coil Off
O
Outcome
Defibrillation thresholds (DFTs) and shock characteristics (impedance, current flow, and shock waveform phase duration)surrogate
Main Result
Absolute Event Rate: 35% vs 54%
p-value: p=<0.0001
In right pectoral ICDs, activating the SVC coil reduces impedance and shortens phase duration, which can either improve or worsen defibrillation thresholds depending on the resulting pulse waveform.
Cite This Study
Varma et al. (2008) conducted an observational in Right pectoral implantable cardioverter defibrillators (n=42). SVC On (proximal coil active) vs. SVC Off was evaluated on Impedance (Ohms) (p=<0.0001). Turning the SVC coil on in right pectoral ICDs significantly reduced impedance (35 vs 54 Ohms, P<0.0001) and shortened phase duration (3.67 vs 5.45 ms, P<0.01) compared to SVC off.