Transient Rotor Activity During Prolonged3-Dimensional PhaseMapping in Human Persistent AtrialFibrillation.

Abstract

This study sought to validate a 3-dimensional (3D) phase mapping system and determine the distribution of dominant propagation patterns in persistent atrial fibrillation (AF). Currently available systems display phase as simplified 2-dimensional maps. We developed a novel 3Dphase mapping system that uses the 3D location of basket catheter electrodes and the patient's 3D left atrial surfacegeometry to interpolate phase and create a 3D representation of phase progression. Six-min AF recordings from the left atrium were obtained in 14 patients using the Constellation basket catheter and analyzed offline. Exported signals underwent both phase and traditional activation analysis and were thenvisualized using a novel 3D mapping system. Analysis involved: 1) validation of phase analysis by comparing beat-to-beat AF cycle length calculated using phase inversion with that determined from activation timing in the same 20-s segment; 2) validation of 3D phase by comparing propagation patterns observed using 3D phase with 3D activationin the same 1-min segment; and 3) determining the distribution of dominant propagation patterns in 6-min recordings using 3D phase. There was strong agreement of beat-to-beat AF cycle length between activation analysis and phase inversion (R2= 0.91). There was no significant difference between 3D activation and 3D phase in mean percentage of propagation patterns classified as single wavefronts (p= 0.99), focal activations (p= 0.26), disorganized activity (p= 0.76), or multiple wavefronts (p= 0.70). During prolonged 3D phase, single wavefronts were the most common propagation pattern (50.2%). Atotal of 34 rotors were seen in 9 of 14 patients. All rotors were transient with mean duration of1.0±0.6 s. Rotors were onlyobserved in areas of high electrode density where the interelectrode distance was significantly shorter than nonrotor sites (7.4 [interquartile range: 6.3 to 14.6] vs. 15.3 mm [interquartile range: 10.1 to 22.2]; p< 0.001). During prolonged 3D phase mapping, transient rotors were observed in 64% of patients and reformed at the same anatomic location in 44% of patients. The electrode density of the basket catheter may limit the detectionofrotors.