September 1, 2000Journal of Cardiovascular Electrophysiology
Prediction of Defibrillation Outcome by Epicardial Activation Patterns Following Shocks Near the Defibrillation Threshold
Key result
Successful defibrillation shocks produce longer intercycle intervals and faster conduction starting at cycle 2.
- P<0.01
- n=5
Why the study?
The relationship between defibrillation outcome and postshock epicardial activation patterns for shocks near the defibrillation threshold was unclear.
Does the postshock epicardial activation pattern predict defibrillation outcome in a pig model of ventricular fibrillation?
Population
5 pigs with induced ventricular fibrillation
Comparison
Successful versus failed defibrillation episodes at approximately ED50 shock strength
Design
Preclinical study with epicardial activation mapping using a 504-electrode array
Authors
Discussion
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Overview
Postshock activation patterns may predict defibrillation outcome in this porcine model; hypothesis-generating and should not yet change clinical practice.
Structured PICO
Does the postshock epicardial activation pattern predict defibrillation outcome in a pig model of ventricular fibrillation?
P
Population
5 pigs undergoing ventricular fibrillation to evaluate epicardial activation patterns following defibrillation shocks.
I
Intervention
10 shocks of approximately ED50 strength (right ventricle-superior vena cava, biphasic, 6/4 msec) delivered after 10 seconds of ventricular fibrillation
C
Comparator
Comparison between successful and failed defibrillation episodes
O
Outcome
Epicardial activation sequences following shocks, including intercycle interval (ICI), wavefront conduction time (WCT), and overlapping indexsurrogate
Main Result
p-value: p=<0.01
An overlapping index >1 in postshock epicardial activation cycles is a marker that predicts failed defibrillation in a porcine model.
Cite This Study
Chattipakorn et al. (2000) studied Ventricular fibrillation (n=5). Defibrillation shocks near ED50 strength vs. Failed defibrillation shocks was evaluated on Intercycle interval (ICI) and wavefront conduction time (WCT) starting at cycle 2 (p=<0.01). Successful defibrillation shocks were characterized by longer intercycle intervals and shorter wavefront conduction times starting at the second postshock cycle compared to failed shocks (P<0.01).