Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04

    • Brefeldin A The efficiency of additional strategies

    2019-07-01

    The efficiency of 2 additional strategies for eliminating the substrate for AF maintenance in addition to PVI has been described. Linear lesions are commonly made at the roof between the contralateral superior PVs (roof line), and at the isthmus between the mitral valve and the left inferior PV (mitral isthmus line) (Fig. 5). This concept was based on previous reports by Hocini et al. [15] and Jaïs et al. [16], in which the combination of both the roof line and the mitral isthmus line improved the AF-free ratio in paroxysmal AF cases from 69% to 87%; however, epicardial RF applications were required in 60% of the cases to achieve the mitral isthmus block. Meta-analysis showed that although the addition of linear lesions did not confer a significant benefit in freedom from AF over PVI alone, a significant benefit was observed for the addition of linear lesions to PVI in persistent AF cases (RR, 0.53) [11]. Adding ganglionated plexus (GP) ablation as an adjunctive approach to other targets may improve ablation success. The 4 major left atrial (LA) GPs (superior left, inferior left, anterior right, and inferior right GP) are located in epicardial fat pads at the border of the PV antrum and can be localized at the time of ablation using high frequency endocardial stimulation [17]. RF current can be applied endocardially at each site with a positive vagal response to high frequency stimulation until the vagal response to high frequency stimulation is eliminated. Although ablation of the left atrial GP has been shown to produce promising results in terms of eliminating the paroxysmal form of AF, its role in ablation of persistent AF remains unclear. Pokushalov et al. [18] demonstrated that GP ablation alone showed only limited effectiveness (38.2%) for long-term maintenance of sinus rhythm in long-standing persistent AF, while the addition of antral PVI resulted in a better success rate (59.6%) over a follow-up Brefeldin A of approximately 1.5 years.
    Sequential multifaceted ablation strategy for chronic AF Multiple strategies consisting of various procedures, including PVI, anatomy- or electrogram-guided left atrial ablation, linear ablation, and thoracic vein isolation, have been developed as discussed above. Each strategy alone has been shown to yield similar success rates (50–70%), suggesting various coexisting targets and factors as modifiers of AF substrates. The stepwise ablation approach is an integration of most of the aforementioned techniques in a bid to additively improve the success of long-standing persistent AF ablation [19]. Each region is targeted in sequence, with the effect of ablation assessed by measuring AF cycle length. The procedure endpoint is the termination of AF to sinus rhythm. According to the progression of the stepwise procedure, the AF-termination rate increased in a sigmoidal fashion (Fig. 6) [20]. Thus far, 5 studies have reported the clinical success associated with the stepwise ablation approach for persistent/long standing persistent AF [19–24]. In an original article by Haissaguerre et al. [19] the single-procedure, drug-free success rate was 62% in 11±6 months, which increased to 88% when repeat procedures were performed in almost 50% of patients. Subsequent articles have demonstrated substantially lower outcomes with success rates of 23–55% when using a single procedure [21–24]. Integration of repeat procedures, mostly for focal atrial tachycardia and flutter, increased the drug-free clinical success rate to 70–88%, and the allowance of previously ineffective antiarrhythmic drug treatment further improved clinical success to 84–90% (Fig. 2) [8].
    A comparison of and the relationship between 2 approaches for long-standing persistent AF: CFAE ablation and linear ablation As mentioned above, both electrogram-based ablation targeting the CFAEs and linear ablation in the left atrium, including roofline ablation and mitral isthmus ablation, have been performed in combination with PVI to eliminate long-persistent atrial fibrillation. Although all these strategies have been shown to be effective, there have been only a few reports demonstrating the relationship between these approaches. PVI has been shown to significantly reduce CFAE regions, and additional ablation targeting the residual CFAE can terminate and eliminate AF during subsequent observation. Matsuo et al. [25] recently demonstrated that both PVI and LA linear ablation resulted in a significant reduction of CFAE areas, not only in the areas where RF was applied, but also in remote regions without RF energy application (Fig. 7). Therefore, reducing the CFAE areas through LA linear ablation could be useful for decreasing the RF energy required for CFAE ablation.