Spatial concentration and distribution of phase singularities in human atrial fibrillation: Insights for the AF mechanism

Abstract

Background Atrial fibrillation (AF) is characterized by the repetitive regeneration of unstable rotational events, the pivot of which are known as phase singularities (PSs). The spatial concentration and distribution of PSs have not been systematically investigated using quantitative statistical approaches. Objectives We utilized a geospatial statistical approach to determine the presence of local spatial concentration and global clustering of PSs in biatrial human AF recordings. Methods 64‐electrode conventional basket (~5 min, n = 18 patients, persistent AF) recordings were studied. Phase maps were produced using a Hilbert‐transform based approach. PSs were characterized spatially using the following approaches: (i) local “hotspots” of high phase singularity (PS) concentration using Getis‐Ord Gi* (Z ≥ 1.96, P ≤ .05) and (ii) global spatial clustering using Moran's I (inverse distance matrix). Results Episodes of AF were analyzed from basket catheter recordings (H: 41 epochs, 120 000 s, n = 18 patients). The Getis‐Ord Gi* statistic showed local PS hotspots in 12/41 basket recordings. As a metric of spatial clustering, Moran's I showed an overall mean of 0.033 (95% CI: 0.0003‐0.065), consistent with the notion of complete spatial randomness. Conclusion Using a systematic, quantitative geospatial statistical approach, evidence for the existence of spatial concentrations (“hotspots”) of PSs were detectable in human AF, along with evidence of spatial clustering. Geospatial statistical approaches offer a new approach to map and ablate PS clusters using substrate‐based approaches.

The inspection paradox: An important consideration in the evaluation of rotor lifetimes in cardiac fibrillation

“…The study also included data from human AF and VF. Human AF data was mapped from previously analysed basket catheter and HD-grid recordings prior to AF ablation ( Dharmaprani et al, 2019a ; Dharmaprani et al, 2019b ; Dharmaprani et al, 2021 ; Schopp et al, 2021 ) For the basket data, 64-electrode basket catheters were used [Constellation, Boston Scientific, 48 mm (4 mm spacing), 60 mm (5 mm spacing)]. Unipolar electrogram recordings were obtained from patient recordings [0.5–500 Hz, 2000 Hz sampling frequency].…”

The Inspection Paradox: An Important Consideration in the Evaluation of Rotor Lifetimes in Cardiac Fibrillation

“…The study also included data from human AF and VF. Human AF data was mapped from previously analysed basket catheter and HD-grid recordings prior to AF ablation (Dharmaprani et al, 2019a;Dharmaprani et al, 2019b;Schopp et al, 2021) For the basket data, 64-electrode basket catheters were used [Constellation, Boston Scientific, 48 mm (4 mm spacing), 60 mm (5 mm spacing)]. Unipolar electrogram recordings were obtained from patient recordings [0.5-500 Hz, 2000 Hz sampling frequency].…”