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Novel methods for characterization of paroxysmal atrial fibrillation in human left atria.

Zhao J, Yao Y, Huang W, Shi R, Zhang S, Legrice IJ, Lever NA, Smaill BH - Open Biomed Eng J (2013)

Bottom Line: Unipolar electrograms were reconstructed at 2048 locations across each LA endocardial surface.The wavelet-based technique and wave-front centroid tracking approach provide a robust means of extracting spatio-temporal characteristics of PAF.The approach could facilitate accurate identification of pro-arrhythmic substrate and triggers, and therefore, to improve success rate of catheter ablation for AF.

View Article: PubMed Central - PubMed

Affiliation: Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.

ABSTRACT

Introduction: More effective methods for characterizing 3D electrical activity in human left atrium (LA) are needed to identify substrates/triggers and microreentrant circuit for paroxysmal atrial fibrillation (PAF). We describe a novel wavelet-based approach and wave-front centroid tracking that have been used to reconstruct regional activation frequency and electrical activation pathways from non-contact multi-electrode array.

Methods: Data from 13 patients acquired prior to ablation for PAF with a 64 electrode noncontact catheter positioned in the LA were analysed. Unipolar electrograms were reconstructed at 2048 locations across each LA endocardial surface. Weighted fine- and coarse-scale electrograms were constructed by wavelet decomposition and combined with peak detection to identify atrial fibrillation (AF) activation frequency and fractionated activity at each site. LA regions with upper quartile AF frequencies were identified for each patient. On the other hand, a wave-front centroid tracking approach was introduced for this first time to detect macro-reentrant circuit during PAF.

Results: The results employing wavelet-based analysis on atrial unipolar electrograms are validated by the signals recorded simultaneously via the contacted ablation catheter and visually tracking the 3D spread of activation through the interest region. Multiple connected regions of high frequency electrical activity were seen; most often in left superior pulmonary vein (10/12), septum (9/12) and atrial roof (9/12), as well as the ridge (8/12). The wave-front centroid tracking approach detects a major macro circuit involving LPVs, PLA, atrial floor, MV, septum, atrial roof and ridge. The regions with high frequency by wave-front tracking are consistent with the results using wavelet approach and our clinical observations.

Conclusions: The wavelet-based technique and wave-front centroid tracking approach provide a robust means of extracting spatio-temporal characteristics of PAF. The approach could facilitate accurate identification of pro-arrhythmic substrate and triggers, and therefore, to improve success rate of catheter ablation for AF.

No MeSH data available.


Related in: MedlinePlus

PAF in the same patient in Fig. (1 and 3) was terminated around the LSPV region at the end of catheter ablation with a stepwise linear approach based on the roof line ablation.
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Figure 8: PAF in the same patient in Fig. (1 and 3) was terminated around the LSPV region at the end of catheter ablation with a stepwise linear approach based on the roof line ablation.

Mentions: The findings reported here are broadly consistent with recent clinical studies on the ablation of PAF. In this study, we have found that high frequency region are most commonly located in the atrial roof, two left PVs, ridge (bounded by LAA, LSPV and LA roof) and two septums (Fig. 7). In contrast, high frequency activity was less common in the atrial floor. Yao and his coworkers noted that the lesions set on the ridge between the LAA and LPVs were most often involved in the termination of AF, both in paroxysmal and persistent AF. Termination of AF was achieved by linear ablation on the ridge area in 52.4% of patients. The Fig. (7) lesions (The RSPV-LSPV LA roof line plus the line along the ridge and LPVs ended at the MV) alone can achieve 77.1% (118 of 153) success rate of the PAF patients. It demonstrates that our approach could detect triggers/substrates of AF and guide catheter ablation. A typical example of the catheter ablation for the PAF patient is displayed in Fig. (8), AF was converted to sinus rhythm around the LSPV region at the end points of catheter ablation with a stepwise linear approach based on the roof line ablation. This study also showed that a linear ablation during an ongoing episode of AF can convert the majority of AFs to SR directly or at least to a more organized type of atrial tachyarrhythmia, i.e, atrial flutter. In this retrospective study, multiple, connected regions of high frequency activation were clearly observed in the same Patient LA, especially in LSPV, ridge, atrial roof (Fig. 6), which explains why Fig. (7) lesions work so effectively for this PAF patient. Our preliminary results on twelve persistent AF (PeAF) using the wavelet approach indicate high frequency regions are located in atrial roof (11/12), ridge (9/12) and the two atrial septums (10/12). The difference in high frequency regions between PAF and PeAF suggests that AF substrates have changed during the transition from PAF to PeAF, therefore, a different ablation strategy is needed for PeAF.


Novel methods for characterization of paroxysmal atrial fibrillation in human left atria.

Zhao J, Yao Y, Huang W, Shi R, Zhang S, Legrice IJ, Lever NA, Smaill BH - Open Biomed Eng J (2013)

PAF in the same patient in Fig. (1 and 3) was terminated around the LSPV region at the end of catheter ablation with a stepwise linear approach based on the roof line ablation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3722539&req=5

Figure 8: PAF in the same patient in Fig. (1 and 3) was terminated around the LSPV region at the end of catheter ablation with a stepwise linear approach based on the roof line ablation.
Mentions: The findings reported here are broadly consistent with recent clinical studies on the ablation of PAF. In this study, we have found that high frequency region are most commonly located in the atrial roof, two left PVs, ridge (bounded by LAA, LSPV and LA roof) and two septums (Fig. 7). In contrast, high frequency activity was less common in the atrial floor. Yao and his coworkers noted that the lesions set on the ridge between the LAA and LPVs were most often involved in the termination of AF, both in paroxysmal and persistent AF. Termination of AF was achieved by linear ablation on the ridge area in 52.4% of patients. The Fig. (7) lesions (The RSPV-LSPV LA roof line plus the line along the ridge and LPVs ended at the MV) alone can achieve 77.1% (118 of 153) success rate of the PAF patients. It demonstrates that our approach could detect triggers/substrates of AF and guide catheter ablation. A typical example of the catheter ablation for the PAF patient is displayed in Fig. (8), AF was converted to sinus rhythm around the LSPV region at the end points of catheter ablation with a stepwise linear approach based on the roof line ablation. This study also showed that a linear ablation during an ongoing episode of AF can convert the majority of AFs to SR directly or at least to a more organized type of atrial tachyarrhythmia, i.e, atrial flutter. In this retrospective study, multiple, connected regions of high frequency activation were clearly observed in the same Patient LA, especially in LSPV, ridge, atrial roof (Fig. 6), which explains why Fig. (7) lesions work so effectively for this PAF patient. Our preliminary results on twelve persistent AF (PeAF) using the wavelet approach indicate high frequency regions are located in atrial roof (11/12), ridge (9/12) and the two atrial septums (10/12). The difference in high frequency regions between PAF and PeAF suggests that AF substrates have changed during the transition from PAF to PeAF, therefore, a different ablation strategy is needed for PeAF.

Bottom Line: Unipolar electrograms were reconstructed at 2048 locations across each LA endocardial surface.The wavelet-based technique and wave-front centroid tracking approach provide a robust means of extracting spatio-temporal characteristics of PAF.The approach could facilitate accurate identification of pro-arrhythmic substrate and triggers, and therefore, to improve success rate of catheter ablation for AF.

View Article: PubMed Central - PubMed

Affiliation: Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.

ABSTRACT

Introduction: More effective methods for characterizing 3D electrical activity in human left atrium (LA) are needed to identify substrates/triggers and microreentrant circuit for paroxysmal atrial fibrillation (PAF). We describe a novel wavelet-based approach and wave-front centroid tracking that have been used to reconstruct regional activation frequency and electrical activation pathways from non-contact multi-electrode array.

Methods: Data from 13 patients acquired prior to ablation for PAF with a 64 electrode noncontact catheter positioned in the LA were analysed. Unipolar electrograms were reconstructed at 2048 locations across each LA endocardial surface. Weighted fine- and coarse-scale electrograms were constructed by wavelet decomposition and combined with peak detection to identify atrial fibrillation (AF) activation frequency and fractionated activity at each site. LA regions with upper quartile AF frequencies were identified for each patient. On the other hand, a wave-front centroid tracking approach was introduced for this first time to detect macro-reentrant circuit during PAF.

Results: The results employing wavelet-based analysis on atrial unipolar electrograms are validated by the signals recorded simultaneously via the contacted ablation catheter and visually tracking the 3D spread of activation through the interest region. Multiple connected regions of high frequency electrical activity were seen; most often in left superior pulmonary vein (10/12), septum (9/12) and atrial roof (9/12), as well as the ridge (8/12). The wave-front centroid tracking approach detects a major macro circuit involving LPVs, PLA, atrial floor, MV, septum, atrial roof and ridge. The regions with high frequency by wave-front tracking are consistent with the results using wavelet approach and our clinical observations.

Conclusions: The wavelet-based technique and wave-front centroid tracking approach provide a robust means of extracting spatio-temporal characteristics of PAF. The approach could facilitate accurate identification of pro-arrhythmic substrate and triggers, and therefore, to improve success rate of catheter ablation for AF.

No MeSH data available.


Related in: MedlinePlus