New aspects of ablation treatment for atrial fibrillation

Bencsik, Gábor
New aspects of ablation treatment for atrial fibrillation.
[Thesis] (Unpublished)

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Catheter ablation using radiofrequency energy has gained acceptance as an effective treatment for atrial fibrillation (AF). Several technical approaches have been developed that correspond to pathophysiological concepts of AF initiation and maintenance.Isolation of pulmonary veins is identified as the cornerstone of any ablation approach.The additional ablation of fragmented or complex ostial or nonostial potentials or left atrial linear ablation has been recently introduced to modify the substrate besides isolating the triggerin order to improve the success rate of AF ablation, especially in patients with persistent AF. In our non-randomized, single-center, observational study we evaluated the acute effects of complex fractionated atrial electrogram (CFAE) ablation guided by automated detection on dominant frequency (DF) and regulatory index (RI) for the fibrillatory process.The termination rate by CFAE ablation was low (12.5% in paroxysmal and 10% in persistent AF). Changes in DF and RI after CFAE ablation were not significant (<0.25 Hz and max. 0.02 increase for RI) in comparison with other ablation steps. Based on our results CFAE ablation guided by a dedicated software algorithm and performed after standard pulmonary vein isolation (PVI) without CFAE remapping does not influence the fibrillatory process significantly. By virtue of the latter CFAE mapping and ablation should be performed always after PVI. With introduction of additional extensive left atrial (LA) ablations the risk of complications have been increased. One of the most devastating complication of AF ablation is atrioesophageal fistula (AEF).Esophageal ulcerations (EU) have been proposed to be potential precursor lesions. In our large single-center study of more than 260 patients, we consistently screened patients for evidence of esophageal injury after AF ablation. In total, we found 2.2% of patients (6 of 267) presenting with EU. Parameters exposing a specific patient to risk of developing EU were persistent AF (5 of 95), additional lines performed (roofline: 6 of 114; LA isthmus: 4 of 49; coronary sinus: 5 of 66), and LA enlargement leading to sandwiching of the esophagus between the LA and thoracic spine. Multivariate analysis revealed LA-to-esophagus distance as the only significant risk factor. Not a single patient with PVI alone developed EU. With the use of a reasonable energy maximum of 25 W at the posterior LA wall using open irrigation catheters, we showed a low percentage of EU creation compared with other studies published. Identifying high-risk patients for esophageal injury 7 potentially has an impact on follow-up or treatment of these individuals by endoscopy or prophylactic treatment. In our substudy (including 31 patients) we assessed the acute effect of radiofrequency ablation (RFA) on distal esophageal acidity using leadless pH-metry capsules. We found that a significant number of patients (19.2%) undergoing RFA of AF develop pathologic acid reflux after ablation. In addition, a subgroup of patients (16.1%) has a preexisting condition of asymptomatic reflux prior to ablation. This finding may explain a potential mechanism for progression of esophageal injury to atrio-esophageal fistulas. We recommend a regular screening for EU in high-risk patients with an extensive lesion set and treatment with proton-pump inhibitor (PPI) medication if EU is discovered. Moreover prophylactic PPI treatment of all patients undergoing RFA of AF have to be considered.

Item Type: Thesis (PhD)
Creators: Bencsik, Gábor
Divisions: Doctoral School of Clinical Medicine
Discipline label: Medicine > Clinical Medicine
Defence date label: 2011. April 14.
Item ID: 742
MTMT id: 2770563
doi: https://doi.org/10.14232/phd.742
Date Deposited: 2011. Apr . 18. 10:58
Last Modified: 2019. Jul . 16. 14:44
URI: https://doktori.bibl.u-szeged.hu/id/eprint/742
Defence/Citable status: Defended.

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