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Brilliant J, Yadav R, Akhtar T, Calkins H, Trayanova N, Spragg D. Clinical and Structural Factors Affecting Ablation Outcomes in Atrial Fibrillation Patients - A Review. Curr Cardiol Rev 2023; 19:83-96. [PMID: 36999694 PMCID: PMC10518883 DOI: 10.2174/1573403x19666230331103153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/16/2023] [Accepted: 02/02/2023] [Indexed: 04/01/2023] Open
Abstract
Catheter ablation is an effective and durable treatment option for patients with atrial fibrillation (AF). Ablation outcomes vary widely, with optimal results in patients with paroxysmal AF and diminishing results in patients with persistent or long-standing persistent AF. A number of clinical factors including obesity, hypertension, diabetes, obstructive sleep apnea, and alcohol use contribute to AF recurrence following ablation, likely through modulation of the atrial electroanatomic substrate. In this article, we review the clinical risk factors and the electro-anatomic features that contribute to AF recurrence in patients undergoing ablation for AF.
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Affiliation(s)
- Justin Brilliant
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
| | - Ritu Yadav
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
| | - Tauseef Akhtar
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
| | - Hugh Calkins
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
| | - Natalia Trayanova
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
| | - David Spragg
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD 21287, United States
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Left atrial voltage mapping: defining and targeting the atrial fibrillation substrate. J Interv Card Electrophysiol 2019; 56:213-227. [PMID: 31076965 PMCID: PMC6900285 DOI: 10.1007/s10840-019-00537-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/12/2019] [Indexed: 12/23/2022]
Abstract
Low atrial endocardial bipolar voltage, measured during catheter ablation for atrial fibrillation (AF), is a commonly used surrogate marker for the presence of atrial fibrosis. Low voltage shows many useful associations with clinical outcomes, comorbidities and has links to trigger sites for AF. Several contemporary trials have shown promise in targeting low voltage areas as the substrate for AF ablation; however, the results have been mixed. In order to understand these results, a thorough understanding of voltage mapping techniques, the relationship between low voltage and the pathophysiology of AF, as well as the inherent limitations in voltage measurement are needed. Two key questions must be answered in order to optimally apply voltage mapping as the road map for ablation. First, are the inherent limitations of voltage mapping small enough as to be ignored when targeting specific tissue based on voltage? Second, can conventional criteria, using a binary threshold for voltage amplitude, truly define the extent of the atrial fibrotic substrate? Here, we review the latest clinical evidence with regard to voltage-based ablation procedures before analysing the utility and limitations of voltage mapping. Finally, we discuss omnipole mapping and dynamic voltage attenuation as two possible approaches to resolving these issues.
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Entropy Mapping Approach for Functional Reentry Detection in Atrial Fibrillation: An In-Silico Study. ENTROPY 2019; 21:e21020194. [PMID: 33266909 PMCID: PMC7514676 DOI: 10.3390/e21020194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/06/2019] [Accepted: 02/15/2019] [Indexed: 12/19/2022]
Abstract
Catheter ablation of critical electrical propagation sites is a promising tool for reducing the recurrence of atrial fibrillation (AF). The spatial identification of the arrhythmogenic mechanisms sustaining AF requires the evaluation of electrograms (EGMs) recorded over the atrial surface. This work aims to characterize functional reentries using measures of entropy to track and detect a reentry core. To this end, different AF episodes are simulated using a 2D model of atrial tissue. Modified Courtemanche human action potential and Fenton–Karma models are implemented. Action potential propagation is modeled by a fractional diffusion equation, and virtual unipolar EGM are calculated. Episodes with stable and meandering rotors, figure-of-eight reentry, and disorganized propagation with multiple reentries are generated. Shannon entropy (ShEn), approximate entropy (ApEn), and sample entropy (SampEn) are computed from the virtual EGM, and entropy maps are built. Phase singularity maps are implemented as references. The results show that ApEn and SampEn maps are able to detect and track the reentry core of rotors and figure-of-eight reentry, while the ShEn results are not satisfactory. Moreover, ApEn and SampEn consistently highlight a reentry core by high entropy values for all of the studied cases, while the ability of ShEn to characterize the reentry core depends on the propagation dynamics. Such features make the ApEn and SampEn maps attractive tools for the study of AF reentries that persist for a period of time that is similar to the length of the observation window, and reentries could be interpreted as AF-sustaining mechanisms. Further research is needed to determine and fully understand the relation of these entropy measures with fibrillation mechanisms other than reentries.
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Iso K, Watanabe I, Kogawa R, Okumura Y, Nagashima K, Takahashi K, Watanabe R, Arai M, Ohkubo K, Nakai T, Hirayama A, Nikaido M. Wavefront direction and cycle length affect left atrial electrogram amplitude. J Arrhythm 2017; 33:269-274. [PMID: 28765756 PMCID: PMC5529329 DOI: 10.1016/j.joa.2017.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/27/2016] [Accepted: 01/13/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The relationship between atrial electrogram (EGM) characteristics in atrial fibrillation (AF) and those in sinus rhythm (SR) are generally unknown. The activation rate and direction may affect EGM characteristics. We examined characteristics of left atrial (LA) EGMs obtained during pacing from different sites. METHODS The study included 10 patients undergoing pulmonary vein isolation for AF. Atrial EGMs were recorded from a 64-pole basket catheter placed in the LA, and bipolar EGM amplitudes from the distal electrode pair (1-2) and proximal electrode pair (6-7) from 8 splines were averaged. The high right atrium (HRA), proximal coronary sinus (CSp), and distal coronary sinus (CSd) were paced at 600 ms and 300 ms. RESULTS When the LA voltage at SR was ≥1.5 mV, bipolar voltages of the HRA were greater than those of the CSp, which were greater than those of the CSd, regardless of the pacing cycle length. The shorter pacing cycle length resulted in a reduction of the LA EGM voltage at sites of SR voltage ≥1.5 mV, but no significant difference was seen at sites where the SR EGM amplitude was between >0.5 and <1.5 mV. No significant differences were seen in intra-basket conduction times between pacing cycle lengths of 600 ms and 300 ms at any pacing site. CONCLUSION The rate and direction-dependent reduction of the amplitude of atrial EGMs may explain, in part, the voltage discordance during SR and AF.
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Affiliation(s)
- Kazuki Iso
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Ichiro Watanabe
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Rikitake Kogawa
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Yasuo Okumura
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Koichi Nagashima
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Keiko Takahashi
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Ryuta Watanabe
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Masaru Arai
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Kimie Ohkubo
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Toshiko Nakai
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
| | - Atsushi Hirayama
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan
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