Spatial characteristics of atrial fibrillation using the surface ECG

The present study investigates spatial properties of atrial fibrillation (AF) by analyzing VCG loops synthesized from 12-lead ECGs. The atrial signal is extracted using spatiotemporal QRST cancellation, and spatial properties are characterized through joint analysis of successive fixed-length signal segments. The significance of spatial (loop morphology) parameters is studied in relation to AF frequency, hypothesizing that more organized AF, being expressed by lower frequency, is associated with decreased variability in loop morphology. The results showed that loop orientation can be determined from global analysis (i.e., the entire 60-s segment is used) or the mean of segment-based analysis, both types of analysis leading to similar results. The hypothesis that more organized AF is associated with decreased variability in loop morphology was to some extent confirmed for the parameters planarity and planar geometry; for 1-s segments, the correlation to AF frequency was 0.608 (ples0.001) and 0.543 (ples0.005).