Background
- Achieving bidirectional mitral isthmus (MI) block using radiofrequency catheter ablation (RFCA) alone is challenging, and MI reconnection is common. Adjunctive vein of Marshall (VOM) ethanol infusion (VOM-Et) can facilitate acute MI block. However, little is known regarding its long-term success. This study sought to evaluate the impact of adjunctive VOM-Et on MI block achievement and durability compared to RFCA alone.
Methods
- Patients undergoing a first attempt of posterior MI ablation were grouped according to their MI block index strategy: adjunctive VOM-Et and RFCA alone. Rates of acute MI block and MI reconnection observed during repeat procedures were compared between the two groups.
Results
- The VOM-Et group consisted of 152 patients (63.8 ± 9.4 years) undergoing adjunctive VOM-Et for MI block. The RFCA group consisted of 110 patients (60.9 ± 9.2 years) undergoing MI ablation using RFCA alone. Acute MI block was more frequently achieved in the VOM-Et group (98.7% [150/152] vs. 63.6% [70/110]; p < 0.001) with shorter RFCA duration (5.00 [3.00-7.00] vs. 19.0 [13.6-22.0] mins; p < 0.001). Of the 220 patients with MI block achieved during the index procedure, 81 underwent a repeat procedure during follow-up (VOM-Et group: 23.3% [35/150] vs. RFCA group: 65.7% [46/70], respectively; p < 0.001). A significantly greater number of patients exhibited durable MI block in the VOM-Et group (62.9% [22/35] vs. 32.6% [15/46], respectively; p = 0.008).
Conclusions
- Beyond facilitating acute MI block, VOM-Et is associated with greater lesion durability as evidenced by higher rates of MI block during repeat procedures.
Aims
Pulsed field ablation (PFA), a non-thermal ablative modality, may show different effects on the myocardial tissue compared to thermal ablation. Thus, this study aimed to compare the left atrial (LA) structural and mechanical characteristics after PFA vs. thermal ablation.
Methods and results
Cardiac magnetic resonance was performed pre-ablation, acutely (<3 h), and 3 months post-ablation in 41 patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation with PFA (n = 18) or thermal ablation (n = 23, 16 radiofrequency ablations, 7 cryoablations). Late gadolinium enhancement (LGE), T2-weighted, and cine images were analysed. In the acute stage, LGE volume was 60% larger after PFA vs. thermal ablation (P < 0.001), and oedema on T2 imaging was 20% smaller (P = 0.002). Tissue changes were more homogeneous after PFA than after thermal ablation, with no sign of microvascular damage or intramural haemorrhage. In the chronic stage, the majority of acute LGE had disappeared after PFA, whereas most LGE persisted after thermal ablation. The maximum strain on PV antra, the LA expansion index, and LA active emptying fraction declined acutely after both PFA and thermal ablation but recovered at the chronic stage only with PFA.
Conclusion
Pulsed field ablation induces large acute LGE without microvascular damage or intramural haemorrhage. Most LGE lesions disappear in the chronic stage, suggesting a specific reparative process involving less chronic fibrosis. This process may contribute to a preserved tissue compliance and LA reservoir and booster pump functions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.