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International Journal of Cardiology Jul 2019Atrial fibrillation (AF) is a complex cardiac arrhythmia with diverse etiology that negatively affects morbidity and mortality of millions of patients. Technological and... (Review)
Review
Atrial fibrillation (AF) is a complex cardiac arrhythmia with diverse etiology that negatively affects morbidity and mortality of millions of patients. Technological and experimental advances have provided a wealth of information on the pathogenesis of AF, highlighting a multitude of mechanisms involved in arrhythmia initiation and maintenance, and disease progression. However, it remains challenging to identify the predominant mechanisms for specific subgroups of AF patients, which, together with an incomplete understanding of the pleiotropic effects of antiarrhythmic therapies, likely contributes to the suboptimal efficacy of current antiarrhythmic approaches. Computer modeling of cardiac electrophysiology has advanced in parallel to experimental research and provides an integrative framework to attempt to overcome some of these challenges. Multi-scale cardiac modeling and simulation integrate structural and functional data from experimental and clinical work with knowledge of atrial electrophysiological mechanisms and dynamics, thereby improving our understanding of AF mechanisms and therapy. In this review, we describe recent advances in our quantitative understanding of AF through mathematical models. We discuss computational modeling of AF mechanisms and therapy using detailed, mechanistic cell/tissue-level models, including approaches to incorporate variability in patient populations. We also highlight efforts using whole-atria models to improve catheter ablation therapies. Finally, we describe recent efforts and suggest future extensions to model clinical concepts of AF using patient-level models.
Topics: Anti-Arrhythmia Agents; Atrial Fibrillation; Catheter Ablation; Computer Simulation; Disease Management; Disease Progression; Heart Atria; Heart Conduction System; Humans
PubMed: 30803891
DOI: 10.1016/j.ijcard.2019.01.077 -
Herzschrittmachertherapie &... Sep 2022In contrast to typical atrial flutter, atypical atrial flutter is a heterogeneous group of right and left atrial macro- or localized reentry tachycardias whose critical...
In contrast to typical atrial flutter, atypical atrial flutter is a heterogeneous group of right and left atrial macro- or localized reentry tachycardias whose critical component for maintaining tachycardia is not the cavotricuspid isthmus. Atypical atrial flutter occurs more frequently after previous catheter ablation and after cardiac surgery. The intraprocedural success rate during ablation is high, although the recurrence rate depends on structural changes in the atria as well as the underlying mechanism. This article provides an overview of the mechanisms as well as mapping and ablation strategies of the most common forms of right and left atrial atypical atrial flutter. This article is part of the "EP Basics" series for targeted continuing education in invasive electrophysiology. Basics, clinic and therapy of atypical atrial flutter are presented with focus on clinically relevant aspects. Procedures and findings of invasive electrophysiological diagnostics and ablation treatment are the focus of this article.
Topics: Atrial Fibrillation; Atrial Flutter; Catheter Ablation; Heart Atria; Humans; Tachycardia
PubMed: 35986095
DOI: 10.1007/s00399-022-00887-3 -
Cardiology Journal 2020Catheter ablation (CA) is a well-known treatment option for patients with symptomatic drug-resistant atrial fibrillation (AF). Multiple factors have been identified to... (Review)
Review
BACKGROUND
Catheter ablation (CA) is a well-known treatment option for patients with symptomatic drug-resistant atrial fibrillation (AF). Multiple factors have been identified to determine AF recurrence after CA, however their predictive value is rather small. Identification of novel predictors of CA outcome is therefore of primary importance to reduce health costs and improve long-term results of intervention. The recurrence of AF following CA is related to severity of left ventricular (LV) dysfunction, extent of atrial dilatation and fibrosis. The aim of this paper was to present and discuss the latest studies on the utility of echocardiographic parameters in terms of CA effectiveness in patients with paroxysmal and persistent AF.
METHODS
PubMed, Google Scholar, EBSCO databases were searched for studies reporting echocardiographic preprocedural predictors of AF recurrence after CA. LV systolic and diastolic function, as well as atrial size, strain and dyssynchrony were taken into consideration.
RESULTS
Twenty one full-text articles were analyzed, including three meta-analyses. Several echocardiographic parameters have been reported to determine a risk of AF recurrence after CA. There are conventional methods that measure left atrial size and volume, LV ejection fraction, parameters assessing LV diastolic dysfunction, and methods using more innovative technologies based on speckle tracking echocardiography to determine left atrial synchrony and strain. Each of these parameters has its own predictive value.
CONCLUSIONS
Regarding CA effectiveness, every patient has to be evaluated individually to estimate the risk of AF recurrence, optimally using a combination of several echocardiographic parameters.
Topics: Atrial Fibrillation; Catheter Ablation; Echocardiography; Heart Atria; Humans; Predictive Value of Tests; Recurrence; Treatment Outcome
PubMed: 29924375
DOI: 10.5603/CJ.a2018.0067 -
International Heart Journal 2022Ablation index (AI)-guided linear ablation is reported to be feasible.We assessed the feasibility of AI-guided left atrial (LA) posterior wall isolations (PWIs) using...
Ablation index (AI)-guided linear ablation is reported to be feasible.We assessed the feasibility of AI-guided left atrial (LA) posterior wall isolations (PWIs) using different target AI values.Seventy-one persistent atrial fibrillation patients who underwent AI-guided PWIs following pulmonary vein isolation were included. LA linear lesions were created with strict contiguity (inter-lesion distance < 4 mm) and different predetermined AI target values (Group-1: 430, Group-2: 450). The data was analyzed retrospectively.The total radiofrequency application time of the roof and bottom-line ablation was a median of 2.8 (2.0, 3.8) and 3.6 (2.8, 4.3) minutes. The first-pass PWI success rate (26/35 [74.3%] versus 16/36 [44.4%], P = 0.011) and a first-pass roof line block (28/35 [80.0%] versus 21/36 [58.3%], P = 0.048) were significantly higher in Group-2 than Group-1, but that for the first-pass bottom line block was similar between Group-1 and Group-2 (29/36 [80.6%] versus 29/35 [82.9%], P = 0.80). Successful PWIs were achieved by additional applications in all. The significant parameter associated with a successful first-pass LA roof line block was a greater RF power, and that for the LA bottom were a higher radiofrequency power and shorter inter-lesion distance. Conduction gaps were mostly located at the middle of both lines. Among 22 roof line gaps, 12 were closed on the line whereas 10 (45.4%) required ablation inside the posterior wall for PWIs. On the contrary, all 11 gaps on bottom lines were closed on the line.Successful first-pass PWIs were obtained in 74% of patients using a target AI value of 450 and strict criteria for the lesion contiguity.
Topics: Atrial Fibrillation; Catheter Ablation; Heart Atria; Humans; Pulmonary Veins; Recurrence; Retrospective Studies; Treatment Outcome
PubMed: 35908854
DOI: 10.1536/ihj.22-091 -
Journal of the American College of... Jul 2020Atrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with...
BACKGROUND
Atrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with sustained AFL.
OBJECTIVES
This study aimed to define the atrial remodeling caused by sustained atrial flutter (AFL) and/or atrial fibrillation (AF).
METHODS
Intercaval radiofrequency lesions created a substrate for sustained isthmus-dependent AFL, confirmed by endocavity mapping. Four groups (6 dogs per group) were followed for 3 weeks: sustained AFL; sustained AF (600 beats/min atrial tachypacing); AF superimposed on an AFL substrate (AF+AFLs); sinus rhythm (SR) with an AFL substrate (SR+AFLs; control group). All dogs had atrioventricular-node ablation and ventricular pacemakers at 80 beats/min to control ventricular rate.
RESULTS
Monitoring confirmed spontaneous AFL maintenance >99% of the time in dogs with AFL. At terminal open-chest study, left-atrial (LA) effective refractory period was reduced similarly with AFL, AF+AFLs and AF, while AF vulnerability to extrastimuli increased in parallel. Induced AF duration increased significantly in AF+AFLs and AF, but not AFL. Dogs with AF+AFLs had shorter cycle lengths and substantial irregularity versus dogs with AFL. LA volume increased in AF+AFLs and AF, but not dogs with AFL, versus SR+AFLs. Optical mapping showed significant conduction slowing in AF+AFLs and AF but not AFL, paralleling atrial fibrosis and collagen-gene upregulation. Left-ventricular function did not change in any group. Transcriptomic analysis revealed substantial dysregulation of inflammatory and extracellular matrix-signaling pathways with AF and AF+ALs but not AFL.
CONCLUSIONS
Sustained AFL causes atrial repolarization changes like those in AF but, unlike AF or AF+AFLs, does not induce structural remodeling. These results provide novel insights into AFL-induced remodeling and suggest that early intervention may be important to prevent irreversible fibrosis when AF intervenes in a patient with AFL.
Topics: Animals; Atrial Fibrillation; Atrial Flutter; Atrial Remodeling; Catheter Ablation; Dogs; Electrocardiography; Fibrosis; Heart Atria
PubMed: 32703507
DOI: 10.1016/j.jacc.2020.05.062 -
Multimedia Manual of Cardiothoracic... Nov 2020Atrial fibrillation is becoming a disease that needs to be addressed with definitive long-term treatment as opposed to medical management options. Ablation or isolation...
Atrial fibrillation is becoming a disease that needs to be addressed with definitive long-term treatment as opposed to medical management options. Ablation or isolation of focal triggers around the pulmonary veins can eliminate arrhythmia substrates for patients with paroxysmal, lone atrial fibrillation. However, limited pulmonary vein isolation strategies do not address reentrant circuits common in persistent and longstanding persistent patients with structural heart disease and enlarged atria. The convergent procedure is a hybrid ablation treatment for atrial fibrillation. It consists of surgical ablation of the posterior left atrium through a minimally invasive closed-chest approach followed by endocardial catheter ablation. The convergent procedure was developed to treat atrial fibrillation by creating a complete and comprehensive pattern of linear lesions on the left atrial backwall under direct endoscopic visualization while avoiding chest incisions and deflation of the lungs. Endocardial ablation follows the epicardial procedure to confirm lesion integrity and supplement the epicardial procedure, which is performed in a staged fashion.
Topics: Atrial Appendage; Atrial Fibrillation; Catheter Ablation; Endocardium; Endoscopy; Heart Atria; Humans; Male; Middle Aged; Organ Size; Pulmonary Veins; Surgery, Computer-Assisted; Treatment Outcome; Xiphoid Bone
PubMed: 33263364
DOI: 10.1510/mmcts.2020.066 -
Journal of Interventional Cardiac... Oct 2022Understanding of the atrial fibrillation (AF) driven by right atrial appendage (RAA) is limited. This study aimed to understand the characteristics of the AF driven by...
PURPOSE
Understanding of the atrial fibrillation (AF) driven by right atrial appendage (RAA) is limited. This study aimed to understand the characteristics of the AF driven by RAA and explore ablation methods.
METHODS
This was a retrospective study and patients who were identified as having the AF driven by RAA were reviewed. Ablation was performed during AF. Potential maps of the left and right atrium, electrophysiological examinations, and ablation methods were studied.
RESULTS
Among the 20 identified patients (mean age 67.0 ± 11.2 years; ejection fraction 62.9 ± 6.0%; LA diameter 43.1 ± 4.9 mm; RA diameter 51.7 ± 8.3 × 42.9 ± 3.7 mm), the AF cycle length in RAA (134.0 ± 10.9 ms) was the shortest, and the fastest frequency potentials were located in the RAA in 65% of patients. For the left atrium, the AF cycle length of the roof (145.5 ± 14.9 ms) was the shortest, followed by the left atrial appendage (153.7 ± 17.1 ms) and bottom (154.8 ± 11.8 ms). High-frequency potentials of RAA could be rapidly conducted to left atrium via sagittal bundle and Bachmann's bundle, and the conduction time (55.0 ± 5.0 ms) was significantly shorter than the mean bi-atrial activation time (176.7 ± 10.3 ms, P < 0.0001). AF could be terminated after ablation at the RAA base (17 patients) or mechanical stimulation within the RAA (3 patients). To date, only two patients had recurrent atrial flutter, while the remaining patients maintained sinus rhythm.
CONCLUSION
The AF driven by RAA is characterized by high-frequency potentials in RAA, and ablation at the RAA base can achieve a satisfactory therapeutic effect.
Topics: Aged; Atrial Appendage; Atrial Fibrillation; Atrial Flutter; Catheter Ablation; Heart Atria; Humans; Middle Aged; Retrospective Studies
PubMed: 35179671
DOI: 10.1007/s10840-021-01106-8 -
The International Journal of... Dec 2022To assess transthoracic echocardiographic (TTE) left atrial (LA) strain parameters and their association with atrial fibrillation (AF) recurrence after thoracoscopic... (Randomized Controlled Trial)
Randomized Controlled Trial
To assess transthoracic echocardiographic (TTE) left atrial (LA) strain parameters and their association with atrial fibrillation (AF) recurrence after thoracoscopic surgical ablation (SA) in patients in sinus rhythm (SR) or in AF at baseline. Patients participating in the Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery trial were included. All patients underwent thoracoscopic pulmonary vein isolation with LA appendage exclusion and were randomized to ganglion plexus (GP) or no GP ablation. In TTEs performed before surgery, LA strain and mechanical dispersion (MD) of the LA reservoir and conduit phase in all patients, and of the contraction phase in patients in SR were obtained. Recurrence of AF was defined as any documented atrial tachyarrhythmia lasting > 30 s during one year of follow-up. Two hundred and four patients (58.6 ± 7.8 years, 73% male, 57% persistent AF) were included. At baseline TTE 121 (59%) were in SR and 83 (41%) had AF. Patients with AF recurrence had lower LA strain of the reservoir phase (13.0% vs. 16.6%; p = < 0.001) and a less decrease in strain of the conduit phase (-9.0% vs. -11.8%; p = 0.006), regardless of rhythm. MD of the conduit phase was larger in patients with AF recurrence (79.4 vs. 43.5 ms; p = 0.012). Multivariate cox regression analysis demonstrated solely an association between LA strain of the reservoir phase and AF recurrence in patients in SR (HR 0.95, p = 0.046) or with AF (HR 0.90, p = 0.038). A reduction in LA strain of the reservoir phase prior to SA predicts recurrence of AF in both patients with SR or AF. Left atrial strain assessment may therefore add to a better patient selection for SA.
Topics: Humans; Male; Female; Atrial Fibrillation; Predictive Value of Tests; Atrial Appendage; Heart Atria; Pulmonary Veins
PubMed: 36445663
DOI: 10.1007/s10554-022-02645-5 -
Current Cardiology Reviews 2021Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter...
Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.
Topics: Atrial Fibrillation; Atrial Remodeling; Catheter Ablation; Comorbidity; Disease Progression; Heart Atria; Humans; Treatment Outcome
PubMed: 32693769
DOI: 10.2174/1573403X16666200721153620 -
JACC. Clinical Electrophysiology Feb 2020The goal of this study was to find effective parameters that can be used in real-time that result in chronic scar verified by left atrial (LA) late gadolinium...
OBJECTIVES
The goal of this study was to find effective parameters that can be used in real-time that result in chronic scar verified by left atrial (LA) late gadolinium enhancement cardiac magnetic resonance (LGE-CMR).
BACKGROUND
Automated annotation can be a useful tool while ablating in tagging areas that will result in scar, but the effective settings that best predict chronic scar are still unknown.
METHODS
Patients underwent pulmonary vein isolation using a CARTO3 mapping system with a VISITAG Module and 3-month post-ablation LGE-CMR. The electroanatomical map (EAM) was used to retrospectively tag ablated areas with 5 different parameters: catheter stability; stability duration; force over time; minimum contact force; and impedance drop. The ablation tags in EAM were projected to the 3-month post-ablation LGE-CMR. Tags were divided into 2 groups depending on if they correlated with CMR-based scar tags (STAGs) or nonscar tags (NTAGs); the effective parameters were estimated for the 2 groups at different power levels.
RESULTS
This study assessed 70 consecutive patients and 28,939 ablation tags. Ablation time and force time integral (FTI) were significantly larger in the STAG group. Mean contact force, change of catheter tip temperature, and impedance were not significantly different between STAGs and NTAGs. The minimum ablation time and FTI to make durable scar lesions were 17.6, 13.6, and 11.0 s and 226.1, 187.4, and 161.4 g at 25, 35, and 50 W, respectively.
CONCLUSIONS
Minimum ablation time and FTI values are critical parameters that determine durable atrial scar creation and their minimum values vary with the ablation power setting.
Topics: Aged; Atrial Fibrillation; Cardiac Imaging Techniques; Catheter Ablation; Cicatrix; Female; Heart Atria; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Pulmonary Veins; Retrospective Studies; Treatment Outcome
PubMed: 32081215
DOI: 10.1016/j.jacep.2019.10.001