Evaluation of the characteristics of rotational activation at high-dominant frequency and complex fractionated atrial electrogram sites during atrial fibrillation

Efficacy of Commonly Used 3D Mapping Systems in Acute Success Rates of Catheter Ablation Procedures

Introduction: This systematic review aims to summarize the procedural arrhythmia termination rates in catheter ablation (CA) procedures of atrial or ventricular arrhythmias using the commonly used mapping systems (CARTO, Rhythmia and EnSite/NavX). Materials and Methods: A systematic search in MEDLINE and Cochrane databases through February 2021 was performed. Results: With regard to atrial fibrillation ablation procedures, acute success rates ranged from 15.4 to 96.0% and 9.1 to 100.0% using the CARTO and EnSite/NavX mapping systems, respectively; acute atrial tachycardia (AT) termination to sinus rhythm ranged from 75 to 100% using the CARTO system. The acute success rate for different types of AT ranged from 75 to 97% using Rhythmia, while the NavX mapping system was also found to have excellent efficacy in the setting of AT, with acute arrhythmia termination rates ranging from 73 to 99%. With regard to ventricular tachycardia, in the setting of ischaemic cardiomyopathy, acute success rates ranged from 70 to 100% using CARTO and 64% using EnSite/NavX systems. The acute success rate using the Rhythmia system ranged from 61.5 to 100.0% for different clinical settings. Conclusions: Mapping systems have played a crucial role in high-density mapping and the observed high procedural success rates of atrial and ventricular CA procedures. More data are needed for the comparative efficacy of mapping systems in acute arrhythmia termination, across different clinical settings.

Spectral characterization and impact of stepwise ablation protocol including LAA electrical isolation on persistent AF

OBJECTIVES

To study how left atrial appendage electrical isolation (LAAEI) impacts atrial dominant frequency (DF) in patients with long-standing persistent atrial fibrillation (LSPAF).

BACKGROUND

LAAEI is associated with a high probability of freedom from atrial fibrillation (AF) and spectral analysis may identify high-frequency sources. How LAAEI impacts the AF dynamics and the subgroup of LSPAF patients in whom LAAEI would be most beneficial, is unclear.

METHODS

Twenty patients with LSPAF were included in the study. Fast Fourier transforms (FFT) were performed on atrial electrograms recorded from 13 sites in the LA and RA. The highest peak frequency was defined as DF.

RESULTS

There was no significant difference in DF between atrial sites except for at the superior vena cava which had the lowest DF at baseline. Stepwise ablation consisting of circumferential pulmonary vein isolation and a linear ablation set of mitral isthmus and roof significantly reduced the DF within the coronary sinus (CS) (5.93 ± 0.98 Hz vs. 5.09 ± 0.72 Hz, p < .05) and the LA posterior wall (LApos) (6.26 ± 0.92 Hz vs. 5.43 ± 0.98 Hz, p < .01). LAAEI preferentially further decreased the DF at the LApos (p < .01), but not at the CS. In cases where there was < 13.6% reduction in the DF of the LApos following the stepwise ablation, the addition of LAAEI was associated with an increased restoration of sinus rhythm (55%, p < .05).

CONCLUSION

LAAEI in addition to stepwise ablation results in further reduction of the DF in the LApos, which is associated with acute termination of AF and favorable ablation outcome.

Ultra-rapid high-density mapping system with the phase singularity technique is feasible in identifying rotors and focal sources and predicting AF termination

INTRODUCTION

Phase singularity (PS) mapping provides additional insight into the AF mechanism and is accurate in identifying rotors. The study aimed to evaluate the feasibility of PS mapping in identifying AF rotors using data obtained from an automatic ultra-rapid high-resolution mapping system with a high-density mini-basket catheter.

METHODS

Twenty-three pigs underwent rapid right atrial (RA) pacing (RAP 480 bpm) for 5 weeks before the experiment. During AF, RA endocardial automatic continuous mappings with a mini-basket catheter were generated using an automatic ultra-rapid mapping system. Both fractionation mapping and waveform similarity measurements using a PS mapping algorithm were applied on the same recording signals to localize substrates maintaining AF.

RESULTS

Seventeen (74%) pigs developed sustained AF after RAP. Three were excluded because of periprocedural ventricular arrhythmia and corrupted digital data. RA fractionation maps were acquired with 6.17 ± 4.29 minutes mean acquisition time, 13768 ± 12698 acquisition points mapped during AF from 581 ± 387 beats. Fractionation mapping identified extensively distributed (66.7%) RA complex fractionated atrial electrogram (CFAE), whereas the nonlinear analysis identified high similarity index (SI > 0.7) parts in limited areas (23.7%). There was an average of 1.67 ± 0.87 SI sites with 0.43 ± 0.76 rotor/focal source/chamber. AF termination occurred in 11/16 (68.75%) AF events in 14 pigs during ablation targeting max CFAE. There was a higher incidence of rotor/focal source at AF termination sites compared with non-AF termination sites (54.5% vs 0%, P = 0.011).

CONCLUSIONS

The data obtained from ultra-rapid high-density automatic mapping is feasible and effective in identifying AF rotors/focal sources using PS technique, and those critical substrates were closely related to AF procedural termination.