Wavelet variance differences in atrial fibrillation during anaesthetic effect

Effect of anaesthetic agents in restoration rhythm procedures during atrial fibrillation (AF) has not been fully investigated. We evaluated the effects of a widely used anaesthetic agent (propofol) in the fibrillation patterns. Intra-atrial recordings belong to 18 patients diagnosed with AF were analyzed ldquobeforerdquo (baseline) and ldquoduringrdquo anaesthetic infusion. The goal of this study is to characterize the variation in atrial properties along the atria in both states. The wavelet variance decomposes the variance of a time series on a scale by scale basis and hence has considerable appeal when physical phenomena are analyzed in terms of variations operating over a range of different scales. Moreover, the variance estimates are more accurately determined with a maximal-overlap version of the wavelet transform (MODWT). As mother wavelet was used the Haar wavelet where the signal was partitioned over seven scales. Wavelet analysis highlights a significant lower changes during the anaesthetic infusion respect to the basal conditions in the right atrium, with an opposite effect and non significant values in the left atrium. The proposed methodology provides an additional approach to the understanding of the role of the anaesthetic, showing a decrease in the variance inter-scales during the anaesthetic infusion in the right atrium, with the opposite effect in the left atrium.