Abstract 1780: Sex Differences Exist in Porcine Ventricular Fibrillation Morphology
Introduction: Animal studies of VF waveform characteristics often include males and females grouped together. The criteria developed from these studies are assumed to apply to all regardless of sex.
Hypothesis: Our hypothesis was that the various measures of quantitative waveform analysis would differ by animal sex and that cutoffs in determining interventions based on these measures should be sex specific.
Methods: VF recordings at 1000 samples/second from 44 swine (25 male, 19 female) available from a previously published study were grouped according to sex. The scaling exponent (ScE) and the logarithm of the absolute correlations (LAC) which are measures of fractal dimension, and the angular velocity (AV), a frequency based measure, were calculated with MATLAB. Three time periods were analyzed: 1 to 5 minutes (electrical phase), 5 to 8 minutes (circulatory phase), and 8 to 11 minutes (metabolic phase).
Results: VF in male animals exhibited increased fractal dimension and a lower angular velocity compared to female animals (fig. 1⇓). In early VF the differences were significant for ScE (p < 0.002), LAC (p < 0.003) and AV (p < 0.006). In VF of intermediate duration differences were significant for LAC (p < 0.02) and show a trend for ScE (p < 0.09) and AV (p < 0.06). For late stage VF differences were not significant: LAC (p < 0.11), ScE (p < 0.43), AV (p < 0.39).
Conclusion: Early VF demonstrates significant differences between male and female swine with regard to both frequency and fractal dimension. VF in males appears to deteriorate more rapidly. These differences will need to be considered when utilizing these measures to determine appropriate therapies.