Optical mapping of ventricular defibrillation in isolated swine right ventricles: demonstration of a postshock isoelectric window after near-threshold defibrillation shocks
Summary
This summary is machine-generated.Optical mapping reveals an isoelectric window after near-threshold defibrillation shocks in swine ventricles. This quiescent period allows ventricular fibrillation to reinitiate, explaining defibrillation failure mechanisms.
Area Of Science
- Cardiovascular Physiology
- Electrophysiology
- Medical Imaging Techniques
Background
- Discrepancy between optical and electrode mapping in observing defibrillation events.
- Importance of understanding defibrillation mechanisms and the isoelectric window.
Purpose Of The Study
- To demonstrate an optical equivalent of the isoelectric window after near-threshold defibrillation shocks.
- To investigate the role of the isoelectric window in defibrillation failure.
Main Methods
- Studied 10 isolated, perfused swine right ventricles using optical mapping.
- Determined upper limit of vulnerability and defibrillation threshold (DFT50).
- Applied near-threshold defibrillation shocks and observed subsequent cardiac electrical activity.
Main Results
- Observed synchronized activation followed by organized repolarization after near-threshold shocks.
- Identified a quiescent period (isoelectric window) of 18+/-24 ms.
- Activation recurred after this window, reinitiating ventricular fibrillation.
Conclusions
- An optical equivalent of the isoelectric window exists after near-threshold defibrillation shocks in swine ventricles.
- Near-threshold shocks terminate wavefronts but fail to prevent defibrillation failure due to reinitiation after the window.
View abstract on PubMed