Abstract
Introduction:
Electrogram morphology recurrence (EMR) analysis is a novel mapping technique which characterizes morphology patterns during atrial fibrillation (AF). Using high resolution electrical mapping, we tested the hypothesis that EMR analysis could identify areas of consistent activation directions and rotor activity in a canine rapid atrial pacing model of AF.
Methods:
Three weeks of rapid right atrial pacing (600 bpm) was performed in six dogs. A triangular plaque was used to obtain 117 simultaneous bipolar AF electrograms from two right and three left atrial locations. EMR plots for each electrogram recording were created by cross-correlation of each activation waveform with each other. The percentage of the most common morphology (REC%) and the mean cycle length (CL) of activations with the most common morphology (CLR) were computed. Activation pattern for each site was classified as either having stable rotors, passive activity, or chaotic activity. Activation vectors were computed and a vector index (VI) was used to measure vector consistency.
Results:
Figure A shows an example of an EMR plot map from recordings in the left atrium with red indicating areas of high EMR. The sites with the shortest CL had an average CL of 81±13 ms. The sites with the highest REC% had an average value of 99±2%. The sites with the shortest CLR had an average value of 91±17 ms. REC% was highly correlated with VI (Figure B). Minimum CL was only moderately shorter in rotor sites compared to chaotic and passive sites (Figure C). Maximum REC% was significantly higher in rotors sites than in chaotic sites, but not different from passive sites (Figure D). Minimum CLR in the rotor sites were significantly less than both the chaotic and passive sites (Figure E).
Conclusions:
EMR analysis is a new mapping technique that correlates well with activation vector consistency and can identify rotor activity. This is a promising method for mapping AF that may identify sources that can be targeted for ablation.