INTEGRATION OF ABSOLUTE VENTRICULAR-FIBRILLATION VOLTAGE CORRELATES WITH SUCCESSFUL DEFIBRILLATION

Previous work has suggested that at higher absolute ventricular fibril latian voltages (AVFV), the heart is more amenable to defibrillation. This study investigated in a canine model whether voltage integration of the AVFV is associated with the defibrillation success rate. The mo ving-average filter was used to process the ventricular fibrillation ( VF) waveform recorded from Lead LI of the electrocardiogram (ECG). In seven animals, defibrillation trials were analyzed using a de shock (D CS) suc- cessful approximately 50% of the time when delivered randomly . For each of a total of 84 DCS (40% successes, 60% failures), the fib rillation waveform just prior to DCS was analyzed. The integration of the AVFV waveform was performed over various sample sizes including 1, 4, 8, 16, 64, and 128 ms, as well as the time equal to the mean VF cy cle length. The results suggest that de shocks delivered at instants o f higher values of integrated AVFV over the various window sizes are a ssociated with successful defibrillation. Window sizes less than 16 ms appeared to offer the best discrimination, The integration of AVFV ov er the entire VF cycle length was significantly higher for successful rather than unsuccessful DCS. This interesting observation is consiste nt with the clinical observation that ''coarse'' VF (high AVFV) is eas ier to defibrillate than ''fine'' VF (low AVFV). The use of voltage in tegration of AVFV may have potential implications in the improvement o f defibrillation success in implantable devices.