Pedro Alexandre Sousa

Background: Outcomes following catheter ablation for persistent atrial fibrillation (AF) remain suboptimal. Low‐voltage areas (LVA), as a surrogate for atrial fibrosis, have been targeted due to their association with arrhythmia recurrence. Ethanol infusion in the vein of Marshall (VoM) has emerged as an adjunctive strategy that may enhance ablation efficacy. We evaluated the effectiveness of a tailored ablation strategy guided by the presence of LVA and incorporating VoM ethanol infusion in patients with persistent AF. Methods: This prospective, single‐center study included patients referred for catheter ablation for persistent AF ablation between August 2022 and August 2024. Patients underwent a tailored ablation strategy guided by the presence of LVA. Procedural endpoints and 1‐year outcomes were assessed and compared with those of a propensity score‐matched cohort undergoing pulmonary vein isolation (PVI) alone. Results: A total of 118 patients (71% male, mean age of 62 ± 10years) were included in our study: 59 in the tailored approach group and 59 propensity score‐matched controls. In the tailored group, VoM ethanol infusion was performed in 60% of patients, while ablation beyond pulmonary veins was not performed in 14% of patients due to LVA absence. Bidirectional block was achieved in all ablation lines except in two patients. At 1‐year follow‐up, 22% of patients had atrial arrhythmia recurrence. The risk of recurrence was significantly lower in the tailored approach group (13.5% vs. 30.5%, p = 0.02). A tailored approach was independently associated with freedom from atrial arrhythmia recurrence (HR 0.41 [0.17–0.94], p = 0.04). No significant differences in adverse events were observed between groups. Conclusions: In patients with persistent AF, a tailored ablation guided by LVAs was associated with significantly lower arrhythmia recurrence at 1‐year compared with PVI alone.

BACKGROUND: Retrograde ethanolization of the vein of Marshall (VOM) has been identified as an adjunct technique in the treatment of persistent atrial fibrillation (AF) and left atrial tachycardia, as stated in the last consensus statement on ablation of AF. However, there is a lack of high-volume data on the technique. METHODS: Through the collection of data from worldwide centers, we performed this international survey that aims to analyze the safety and procedural characteristics of VOM ethanolization in patients referred for treatment of AF or left atrial tachycardia. RESULTS: We included 5579 patients (66 years; range, 20–93) from 26 centers, who underwent VOM ethanolization between 2008 and 2024 for persistent AF (81%), paroxysmal AF (9%), or left atrial tachycardia (10%) under deep sedation (53%) or general anesthesia (47%). A concomitant mitral isthmus line was attempted in 79% of the cases, achieving mitral isthmus block in 98% of patients. There were 0.92% of periprocedural serious adverse events, including 0.09% of peri-procedural death (5 patients). Three patients developed hemodynamic collapse immediately after VOM ethanolization, causing the death of 1 due to anaphylactic shock. One patient died following surgical drainage of pericardial effusion 3 weeks after the procedure. The 3 other deaths were not directly related to VOM ethanolization. Pericardial effusion was observed in 123 patients (2.2%) at the time of or immediately after the procedure, requiring drainage in 20 patients (0.36%) and later in 32 additional patients (0.57%), including 5 (0.09%) requiring drainage. Pacemaker implantation was required in 2 patients (0.04%), 1 for high-grade atrioventricular block and 1 for sinus node dysfunction. CONCLUSIONS: This international survey shows that VOM ethanolization is predominantly performed in patients with persistent AF. It is associated with rare but potentially life-threatening adverse events. Mitral isthmus line ablation results in a very high rate of block when performed concomitantly.

Background: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation (CA) for atrial fibrillation (AF), yet outcomes remain suboptimal in persistent AF patients. Ethanol infusion in the vein of Marshal (VoM), an embryological remnant implicated in AF pathogenesis, may enhance ablation efficacy. Objective: To evaluate the effectiveness of VoM ethanol infusion in patients with persistent AF. Methods: We conducted a systematic review and meta‐analysis of randomized controlled trials (RCT) comparing CA with versus without VoM ethanol infusion in patients undergoing first‐time ablation of persistent AF. The primary endpoint was freedom from any atrial arrhythmia in a 12‐month follow‐up. Results: Four RCTs including 1045 patients were analyzed (VoM + CA—535 patients vs. CA alone—510 patients). Ethanol infusion in the VoM significantly increased freedom from atrial arrhythmias (RR 1.21; 95% CI 1.010–1.32; p < 0.0001, NNT 10) and reduced the need of a repeat procedure (RR 0.63; 95% CI 0.45–0.87; p = 0.005). Mitral isthmus (MI) block was more frequently achieved in the VoM group (RR 1.30; 95% CI 1.03–1.65; p = 0.03) There was no significant difference in the rate of major complications (2.8% vs. 3.5%, RR 0.72; 95% CI 0.37–1.43; p = 0.35, NNH 138), although overall complications were more frequent in the VoM ethanol infusion group (RR 2.25; 95% CI 1.08–4.70; p = 0.03). Conclusion: When added to CA, ethanol infusion in the VoM improves freedom from arrhythmia without increasing the risk of major complications. These findings may support its integration into ablation strategies for persistent AF.

Background: An accurate local activation time (LAT) map is essential during premature ventricular contraction (PVC) ablation. The aim of this study was to evaluate whether the use of a novel octaspline multielectrode catheter, with and without the use of a catheter‐embedded unipolar reference, improves LAT mapping during PVC ablation compared to a pre‐existing pentaspline mapping catheter. Methods: This study prospectively assessed 10 consecutive patients referred for PVC ablation from January to June 2023. Three 12‐min LAT maps were performed in each patient using three different strategies: pentaspline catheter + unipolar reference in the inferior vena cava (IVC) versus octaspline catheter + unipolar in the IVC versus octaspline catheter + unipolar embedded in the mapping catheter. Acute procedural and midterm endpoints were assessed. Results: The use of an octaspline catheter increased the number of total LAT points (1010 ± 451 vs. 397 ± 213, p = 0.001), LAT points near the successful RF ablation site (118 ± 105 vs. 21 ± 19, p = 0.010) and electrograms (EGM) per PVC (23 ± 21 vs. 7 ± 3, p = 0.032), while reducing mapping duration (65 ± 41 EGM/min vs. 21 ± 8 EGM/min, p = 0.003). However, signal resolution was not superior to that obtained with the pentaspline catheter, with similar bipolar ( p = 0.505) and unipolar ( p = 0.176) voltages, an increased bipolar signal duration ( p = 0.003) and a reduction in the unipolar signal duration ( p = 0.013). Use of a catheter‐embedded unipolar reference led to shorter unipolar signal duration (76 ± 34 ms vs. 142 ± 29 ms, p < 0.001), and provided an earlier unipolar signal deflection to QRS onset (−24 ± 16 ms vs. −19 ± 11 ms, p = 0.006) and earlier −dV/dT signal annotation (−12 ± 10 ms vs. −7 ± 9 ms, p < 0.001). This subsequently led to a shorter distance from the earliest LAT to successful RF site ( p = 0.014). No significant differences between multielectrode mapping catheters were seen regarding catheter‐induced ectopy rate ( p = 0.703). Conclusions: The use of an octaspline catheter combined with an embedded unipolar reference may associate with faster, more detailed and accurate activation mapping in the setting of PVC ablation.

Aims: We aimed to assess the acute and midterm efficacy of premature ventricular contraction (PVC) ablation guided by multielectrode and point-by-point (PbP) mapping. Methods and results: This is a retrospective, international multicentre study of consecutive patients referred for PVC ablation in 10 hospital centres from January 2017 to December 2021. Based on the mapping approach, two cohorts were identified: the ‘Multipolar group’, where a dedicated high-density mapping catheter was employed, and the ‘PbP group’, where mapping was performed with the ablation catheter. Procedural endpoints, safety, and acute (procedural) and midterm efficacies were assessed. Of the 698 patients included in this study, 592 received activation mapping [46% males, median age of 55 (41–65) years]—248 patients in the Multipolar group and 344 patients in the PbP group. A higher number of activation points [432 (217–843) vs. 95 (42–185), P < 0.001], reduced mapping time (40 ± 38 vs. 61 ± 50 min, P < 0.001), and shorter procedure time (124 ± 60 vs. 143 ± 63 min, P < 0.001) were reported in the Multipolar group. Both groups had high acute success rates (84.7% with Multipolar mapping vs. 81.3% with PbP mapping, P = 0.63), as well as midterm efficacy (83.4% vs. 77.4%, P = 0.08), with no significant differences in the risk of adverse events (6.0% vs. 3.5%, P = 0.24). However, for left-sided PVC ablation specifically, there was a higher midterm efficacy in the Multipolar group (80.7% vs. 69.5%, P = 0.04), with multipolar mapping being an independent predictor of success [adjusted OR = 2.231 (95% CI, 1.476–5.108), P = 0.02]. Conclusion: The acute and midterm efficacies of PVC ablation are high with both multipolar and PbP mapping, although the former allows for quicker procedures and may potentially improve the outcomes of left-sided PVC ablation.

Background: Ablation Index (AI) software has allowed better atrial fibrillation (AF) ablation results, but recurrence rates remain significant. Specific serum biomarkers have been associated with this recurrence. Objectives: To evaluate whether certain biomarkers could be used (either individually or combined) to predict arrhythmia recurrence after AI-guided AF ablation. Methods: Prospective multicenter observational study of consecutive patients referred for AF ablation from January 2018 to March 2021. Hemoglobin, brain natriuretic peptide (BNP), C-reactive protein, high sensitivity cardiac troponin I, creatinine clearance, thyroid-stimulating hormone (TSH) and free thyroxine (FT4) were assessed for their ability to predict arrhythmia recurrence during follow-up. Statistical significance was accepted for p values of1.8 μUI/mL (HR=1.82 [95% CI, 1.89-2.80], p=0.006) was an independent predictor of arrhythmia recurrence. When assessing TSH, FT4 and BNP values in combination, each additional “abnormal” biomarker value was associated with a lower freedom from arrhythmia recurrence (87.1 % for no biomarker vs. 83.5% for one vs. 75.1% for two vs. 43.3% for three biomarkers, p<0.001). Patients with three “abnormal” biomarkers had a threefold higher risk of AF recurrence compared with no “abnormal” biomarker (HR=2.88 [95% CI, 1.39-5.17], p=0.003). Conclusions: When used in combination, abnormal TSH, FT4 and BNP values can be a useful tool for predicting arrhythmia recurrence after AI-guided AF ablation.

Resumo Fundamento: O software ablation index (AI) permitiu melhorar os resultados da ablação de fibrilação atrial (FA), mas as taxas de recorrência permanecem significativas. Biomarcadores séricos específicos têm sido associados a essa recorrência. Objetivos: Avaliar se certos biomarcadores podem ser utilizados (individualmente ou combinados) para predizer a recorrência de FA pós ablação guiada pelo AI. Métodos: Estudo multicêntrico, observacional, prospectivo de pacientes consecutivos, encaminhados para ablação de FA de janeiro de 2018 a março de 2021. Hemoglobina, peptídeo natriurético cerebral (BNP), proteína C reativa, troponina I ultrassensível, clearance de creatinina, Hormônio Tireoestimulante (TSH), e Tiroxina livre (T4) foram avaliados quanto à capacidade de prever a recorrência de arritmias durante o acompanhamento. Valores de p 1,8 μUI/mL [HR=1,82 (IC95%, 1,89-2,80), p=0,006] foi um preditor independente de recorrência. Avaliando-se a combinação de TSH, FT4 e BNP, a adição de cada valor “anormal” foi associada a uma menor sobrevida livre de recorrência (87,1% se nenhum vs. 83,5% se um vs. 75,1% se dois vs. 43,3% se três biomarcadores, p<0,001). Doentes com três biomarcadores “anormais” apresentaram três vezes maior probabilidade de recorrência de FA, comparativamente aos que não apresentaram nenhum biomarcador “anormal” (HR=2,88 [IC95%, 1,39-5,17], p=0,003). Conclusões: Quando combinados, valores anormais de TSH, FT4 e BNP podem ser uma ferramenta útil para prever a recorrência de FA pós ablação guiada pelo AI.