Abstract 16953: Noninvasive Detection of Atrial Fractionation (Fibrosis) Using Signal-Averaging of the P-Wave
INTRODUCTION: Atrial fibrosis is a common finding in patients with atrial fibrillation (AF). We hypothesized that atrial fibrosis causes disordered conduction, resulting in fractionation of the P-wave in the surface ECG.
METHODS: High-fidelity (1000 samples/sec, 0.5 uV per LSB) 12-lead ECGs were recorded for 10 min in 3 groups, all in sinus rhythm: 1) 20 pts post-AF ablation, ABL (14/6 M/F, ave age 63); 2) 19 pts with paroxysmal AF, PAF (12/7 M/F, ave age 65); and. 3) 20 normal young subjects, NRM (10/10 M/F, ave age 34). We signal-averaged P waves in each lead (100’s of clean beats) and measured fractionation with three metrics: number, magnitude and duration of deflections (DEF) between adjacent local extrema having magnitudes greater than lead-specific thresholds based on T-P interval segment noise. Significance was tested using Kolmogorov-Smirnov statistics.
RESULTS: Probability distribution functions of the number and duration of deflections are shown in the Figure. ABL and PAF pts had more, smaller, and shorter DEF than NRM (p<0.001, left), but also DEF magnitudes were significantly different between ABL and PAF patients (p<0.001), with ABL pts having a narrower range (p<0.001). DEF duration was clearly shorter in AF pts compared to NRM (right), but ABL pts had shorter DEF than PAF pts (p<0.025). DEF magnitude was much longer in NRM compared to AF (p<0.0001), with only a weak (p<0.1) difference between ABL and PAF (graph not shown).
CONCLUSIONS: These results suggest that impulse conduction across the atria in AF pts is highly fractionated, probably caused by diffuse localized conduction block induced by fibrosis and disease. Further, the results imply that the amount of disrupted conduction can be quantitated, in that ABL pts have more fractionation than PAF pts. Further studies are needed to know if this technique can be used to predict future AF.
- © 2012 by American Heart Association, Inc.