The Intrinsic Autonomic Nervous System in Atrial Fibrillation: A Review

The procedure of catheter ablation for the treatment of drug resistant atrial fibrillation (AF) has evolved but still relies on lesion sets intended to isolate areas of focal firing, mainly the myocardial sleeves of the pulmonary veins (PVs), from the rest of the atria. However the success rates for this procedure have varied inversely with the type of AF. At best success rates have been 20 to 30% below that of other catheter ablation procedures for Wolff-Parkinson-White syndrome, atrioventricular junctional re-entrant tachycardia and atrial flutter. Basic and clinical evidence has emerged suggesting a critical role of the ganglionated plexi (GP) at the PV-atrial junctions in the initiation and maintenance of the focal form of AF. At present the highest success rates have been obtained with the combination of PV isolation and GP ablation both as catheter ablation or minimally invasive surgical procedures. Various lines of evidence from earlier and more recent reports provide that both neurally based and myocardially based forms of AF can separately dominate or coexist within the context of atrial remodeling. Future studies are focusing on non-pharmacological, non-ablative approaches for the prevention and treatment of AF in order to avoid the substantive complications of both these regimens.

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Imaging of pulmonary veins during catheter ablation for atrial fibrillation: the role of multi-slice computed tomography

EP Europace ◽

10.1093/europace/eun230 ◽

2008 ◽

Vol 10 (Supplement 3) ◽

pp. iii14-iii21 ◽

Cited By ~ 12

Author(s):

H. Niinuma ◽

R. T. George ◽

A. Arbab-Zadeh ◽

J. A.C. Lima ◽

C. A. Henrikson

Keyword(s):

Computed Tomography ◽

Atrial Fibrillation ◽

Catheter Ablation ◽

Pulmonary Veins

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Abstract 16896: Electrogram Morphology Recurrence to Characterize Drivers of Persistent Atrial Fibrillation: Findings at Initial versus Redo Catheter Ablation

Circulation ◽

10.1161/circ.142.suppl_3.16896 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Ghaith Zaatari ◽

Jorge Bohorquez ◽

Raul Mitrani ◽

Jason Ng ◽

Justin Ng ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Cycle Length ◽

Cross Correlation ◽

Pulmonary Veins ◽

Persistent Atrial Fibrillation ◽

Success Rates ◽

Mapping Tool ◽

Group 2 ◽

Group 1

Background: Electrogram (EGM) morphology recurrence (EMR) mapping of persistent atrial fibrillation (PeAF) quantifies consistency of activation at each site and is expected to be high and rapid near drivers of PeAF. Objective: To compare EMR in the left (LA) and right atrium (RA) in patients undergoing first- vs second-time PeAF catheter ablation (CA). Methods: Multisite bipolar EGM mapping of the LA (265±153 sites) and RA (224±148 sites) prior to CA for PeAF was performed in 40 patients (29 males, age 63±9 yrs, CHA2DS2-VASc 2.4±1.5, LVEF 48±12%) undergoing first (Group 1, n=31) or second-time (Group 2, n=9) CA. After cross-correlation of each automatically detected EGM with every other EGM in the recording, the most recurrent EGM morphology was identified and its frequency (Rec%) and cycle length of recurrence (CL R ) were computed (figure). The minimum CL R sites were identified. Results: In group 1, shortest CL R was in the LA in 26 patients (84%) and RA in 5 patients (16%). In the LA, there were 1 (n=23), 2 (n=2), or 3 (n=1) areas of shortest CL R , most commonly in the pulmonary veins (PV; n=19). In the RA, there was only 1 area of shortest CL R . Minimum CL R was 174.1±25.4 ms (LA-179.6±37.4 vs RA-207.9±34.5, p=0.0004), with Rec% 95±10%. In group 2, shortest CL R was in the LA in 5 patients and RA in 5 patients (56%)– one had both LA and RA. In the LA/RA, there were 1 (n=3/4) or 2 (n=2/1) areas of shortest CL R . The most common LA site was non-PV (6/7, 85.7%). The minimum CL R was 182.1±26.2ms (LA-190.8±36.2 vs RA-196.0±30.5, p=0.6), with Rec% 96±5%. Conclusion: In 61% of patients undergoing initial CA for PeAF, EMR identified LA drivers in the PVs which may explain why PV isolation has been reported to have 50-60% success rates in PeAF. In patients undergoing a 2 nd ablation for PeAF, EMR identified predominantly nonPV drivers with even distribution of shortest CL R between RA and LA and diminished CL R gradient between the LA and RA. EMR may be a useful mapping tool to characterize potential drivers of PeAF.

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Long-standing Persistent Atrial Fibrillation Ablation: the Role of the Inter- and Intra-atrial Bundles

Journal of Cardiac Arrhythmias ◽

10.24207/jca.v33i2.3368 ◽

2020 ◽

Vol 33 (2) ◽

pp. 73-81

Author(s):

Russell Mitchell ◽

Cesar Augusto Bonilla Isaza

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Clinical Outcomes ◽

Pulmonary Veins ◽

Persistent Atrial Fibrillation ◽

Conduction System ◽

Atrial Fibrillation Ablation ◽

Anatomical Location

Catheter ablation has become the mainstream treatment of atrial fibrillation, but still remains a challenge in those patient with persistent and long standing persistent atrial fibrillation. In addition of isolation of the pulmonary veins, any other areas that can trigger or perpetuate atrial fibrillation need to be isolated. Current technologies may allow to effectively deliver permanently lasting lesions, and therefore improve clinical outcomes after ablation. The specialized conduction system including the Bachmann and septopulmonary bundles, are important substrate targets for the management of atrial fibrillation. The anatomical location of these fibers, and the corresponding approach for ablation are described in this case.

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The Key Role of Uric Acid in Oxidative Stress, Inflammation, Fibrosis, Apoptosis, and Immunity in the Pathogenesis of Atrial Fibrillation

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.641136 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yawen Deng ◽

Fei Liu ◽

Xiaolei Yang ◽

Yunlong Xia

Keyword(s):

Oxidative Stress ◽

Atrial Fibrillation ◽

Risk Factor ◽

Clinical Evidence ◽

Scientific Evidence ◽

Critical Role ◽

Adverse Outcomes

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to numerous adverse outcomes including stroke, heart failure, and death. Hyperuricemia is an important risk factor that contributes to atrium injury and AF, but the underlying molecular mechanism remains to be elucidated. In this review, we discussed the scientific evidence for clarifying the role of hyperuricemia in the pathogenesis of AF. Experimental and Clinical evidence endorse hyperuricemia as an independent risk factor for the incidence of AF. Various in vivo and in vitro investigations showed that hyperuricemia might play a critical role in the pathogenesis of AF at different UA concentrations through the activation of oxidative stress, inflammation, fibrosis, apoptosis, and immunity.

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Új felismerések a pitvarfibrilláció genezisében és fenntartásában: az egyénre szabott kezelés lehetőségei

Orvosi Hetilap ◽

10.1556/650.2018.31087 ◽

2018 ◽

Vol 159 (28) ◽

pp. 1135-1145

Author(s):

Szilvia Kugler ◽

Gábor Duray ◽

István Préda

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Pulmonary Veins ◽

Management Strategies ◽

Anticoagulation Therapy ◽

Progressive Increase ◽

Renal Sympathetic Denervation ◽

Atrial Remodeling ◽

Linear Lesions ◽

Obstructive Sleep

Abstract: Atrial fibrillation affects approximately three percent of the adults. Ablation strategies targeting the isolation of the pulmonary veins are the up-to-date cornerstones for atrial fibrillation ablations. However, a one-year success rate of repeated interventions is not more than 70%. Long-term efficacy of catheter ablation is presumably limited by electrical and structural remodeling of the atria, which results in a progressive increase in the duration of atrial fibrillation to become sustained. The potential pathophysiological importance of the epicardial adipose tissue, atrial fibrosis, autonomic nervous system and arrhythmogenic foci are documented by several studies. Increased volume, inflammation induced transformation to fibrosis and myocardial infiltration of atrial subepicardial fat in obese patients result in higher risk of atrial fibrillation development. Changes in atrial autonomic innervation under some conditions including regular physical exercise strongly promote arrhythmogenesis via the mechanism of enhanced triggered activity or abbreviated atrial refractoriness. Individualized management of possible trigger and substrate mechanisms are proposed to provide a novel basis for the effective treatment of atrial fibrillation. Pro-fibrotic signalling pathways can be inhibited by the suppression of renin-angiotensin-aldosterone system. Neuromodulation strategies include renal sympathetic denervation and ganglionic plexi ablation. Anticoagulation therapy has also been shown to reduce the burden of abnormal atrial remodeling. Possible novel catheter ablation techniques are used for right or left atrial linear lesions, scar homogenization and catheter ablation of complex fractionated atrial electrograms, rotors or ectopic foci. Beside these new management strategies, clinical consideration of factors of particular risks as obesity, hyperlipidaemia, hypertension, diabetes and obstructive sleep apnoe are also essential. Orv Hetil. 2018; 159(28): 1135–1145.

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Abstract 738: Role of the Pulmonary Veins in Experimental Paradigms of Remodeling- Basic Science Associated Atrial Fibrillation

Circulation ◽

10.1161/circ.116.suppl_16.ii_139-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Masao Sakabe ◽

Kristina Lemola ◽

Katsuyoshi Chiba ◽

Grigorios Katsouras ◽

Akiko Shiroshita-Takeshita ◽

...

Keyword(s):

Atrial Fibrillation ◽

Pulmonary Veins ◽

Rate Adaptation ◽

Ventricular Rate ◽

Atrial Remodeling ◽

List Type ◽

Ablation Therapy ◽

Before And After ◽

The Mean

Background : Pulmonary vein (PV) activity is crucial in some forms of clinical atrial fibrillation (AF), particularly paroxysmal lone AF. The precise importance of PVs in AF associated with structural heart disease is less clear. Some evidence suggests that PVs may be important for AF in experimentally-remodeled atrial substrates, e.g. atrial-tachycardia remodeling (ATR) and congestive heart failure (CHF)-induced structural remodeling, but contradictory findings also exist. This study assessed the role of PVs in canine remodeling-associated AF by evaluating the changes induced by PV-LA disconnection via encircling epicardial ablation. Methods: AF was induced before and after complete isolation of all PVs in dogs with: ATR induced by atrial tachypacing (400 bpm x 1 wk; with AV block and 80 bpm ventricular pacing to control ventricular rate, n=5); and CHF induced by ventricular tachypacing (VTP, 240 bpm x 2 wks, n=7). Electrophysiological measurements and AF mapping with 240 unipolar atrial electro-grams in both atria and all PVs were also obtained before and after PV isolation. Results ATR reduced atrial ERPs and ERP rate adaptation. The shortest AF cycle length (AFCL) in each ATR dog was recorded from PVs (mean 84±3 ms), but the mean AFCL in each of the PVs (range 97–103 ms) was not different from the mean AFCL at LA sites (98 –103 ms). PV ablation did not affect AF duration in ATR dogs (mean 284±265 pre- vs. 304±225 s post-ablation, P=NS), nor did it significantly alter RA or LA AFCL. In CHF dogs, ERPs and ERP rate adaptation were preserved. The shortest AFCL was recorded in PVs in 2 dogs (108,112 ms) and in the left side of Bachmann’s bundle in 3 (97–117 ms). PV ablation failed to alter AF duration in CHF dogs (mean 778±203 pre- vs. 644±206 s post-ablation), and increased AFCL in RA and LA slightly (10 –15%) but not significantly. Conclusions : Uncoupling of the PVs from the LA fails to significantly affect the AF substrate in 2 clinically-relevant animal paradigms of AF-promoting atrial remodeling. These findings suggest that in the presence of a favorable atrial substrate for AF the PVs are not needed for AF maintenance, and are consistent with clinical observations that complete PV isolation may not be essential for effective ablation therapy of all groups of AF patients.

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Role of transoesophageal echocardiography in evaluating the effect of catheter ablation of atrial fibrillation on anatomy and function of the pulmonary veins

EP Europace ◽

10.1093/europace/eun188 ◽

2008 ◽

Vol 10 (9) ◽

pp. 1079-1084 ◽

Cited By ~ 7

Author(s):

B. De Piccoli ◽

A. Rossillo ◽

C. Zanella ◽

A. Bonso ◽

S. Themistoclakis ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Pulmonary Veins ◽

Transoesophageal Echocardiography ◽

And Function

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Rotor Drivers in Induction and Maintenance of Atrial Fibrillation

Rational Pharmacotherapy in Cardiology ◽

10.20996/1819-6446-2021-04-16 ◽

2021 ◽

Vol 17 (2) ◽

pp. 270-277

Author(s):

A. A. Kulikov ◽

O. V. Sapelnikov ◽

T. M. Uskach ◽

D. I. Cherkashin ◽

I. R. Grishin ◽

...

Keyword(s):

Atrial Fibrillation ◽

Radiofrequency Ablation ◽

Catheter Ablation ◽

Success Rate ◽

Dominant Role ◽

Pulmonary Veins ◽

Limited Effect ◽

Increased Risk ◽

Further Development

Atrial fibrillation is the most common arrhythmia in clinical practice. It is associated with an increased risk of stroke, chronic heart failure, and sudden cardiac death. Our options of restoring and maintaining sinus rhythm have a very limited effect, both in the case of antiarrhythmic and catheter treatment. Catheter ablation has proven to be a more effective approach than antiarrhythmic therapy. The success rate of the procedure reaches 70%. However, radiofrequency ablation is associated with a risk of complications, with 4.5% of patients likely to develop major complications, including tamponade (1.31%), femoral pseudoaneurysm (0.71%), and death (0.15%). Given the generally recognized dominant role of the pulmonary veins in the induction of atrial fibrillation, their electrical isolation has become the recommended tactic of the catheter approach. In the case of patients with paroxysmal form of atrial fibrillation, the success rate of the procedure reaches 87%. Unfortunately, in the case of persistent forms of atrial fibrillation, the effectiveness of the primary procedure decreases to 28% and reaches 51% with repeated interventions. In addition to the anatomically oriented isolation of the pulmonary veins, a number of strategies have been proposed to reach the secondary zones of atrial fibrillation induction. The results of recent studies on the effectiveness of strategies for ablation of rotor regions and their role in the induction and maintenance of AF may lead to the further development of catheter ablation techniques and an individual radiofrequency ablation approach in a particular patient.

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