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Background: Electroanatomical mapping is an essential tool in the ablation of typical AFL., Objectives: To identify the existence of voltage patterns in the CTI voltage maps and their relevance for typical AFL ablation., Methods: A voltage map of the CTI was made prior to ablation, identifying the areas of maximum voltage and their location along the CTI, allowing classification into patterns according to their distribution. A stepwise ablation approach targeting the areas of maximum voltage was conducted. The ablation characteristics were compared based on the pattern obtained., Results: Two voltage patterns were identified, with differences in ablation time to bidirectional CTI block. No complications occurred., Conclusions: Voltage mapping identifies patterns in the CTI with implications for typical AFL ablation., Competing Interests: The authors declare no conflict of interest., (© 2024 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

Background: Ablation of atrial fibrillation (AF), both cryoablation ablation (CBA) and radiofrequency catheter ablation (RFCA), have demonstrated to be safe and effective. About 1 in 3 patients may face a redo due to recurrence and the best technique is unknown. The aim of this study is to assess the efficacy of CBA as a repeat procedure in patients with prior CBA or RFCA., Methods: A nation-wide CBA registry (RECABA) was analyzed and patients were compared who had previously undergone CBA (Prior-CB) or RFCA (Prior-RF). The primary endpoint was AF recurrence at 12 months after a 3-month blanking period. A survival analysis was performed, univariate and multivariate Cox models were also built., Results: Seventy-four patients were included. Thirty-three (44.6%) were in the Prior-CB group and 41 (55.4%) in the Prior-RF. There were more reconnected pulmonary veins in the Prior-RF than in Prior-CB group (40.4% vs.16.5%, p = 0.0001). The 12-month Kaplan-Meier estimate of freedom from AF recurrence after the blanking period was 61.0% (95% confidence interval [CI] 41.4-75.8%) in the Prior-CB, and 89.2% (95% CI 73.6-95.9%) in the Prior-RF group (p = 0.002). Multivariate Cox regression pointed Prior-CB as the sole independent predictor of AF recurrence, with an adjusted HR of 2.67 (95% CI 1.05-6.79)., Conclusions: Repeat CBA shows higher rates of AF recurrences compared to CBA after a previous RFCA despite presenting less reconnected veins at the procedure. These data suggest that patients with AF recurrence after CBA may benefit from other ablation techniques after a recurrence. RECABA is registered at clinicaltrials.gov with the Unique Identifier NCT02785991.

Background: Implantable cardioverter defibrillators (ICD) are effective as a primary prevention measure of ventricular tachyarrhythmias in patients with ST-segment elevation myocardial infarction (STEMI) and depressed left ventricular ejection fraction (LVEF). The implications of using cardiac magnetic resonance (CMR) instead of echocardiography (Echo) to assess LVEF prior to the indication of ICD in this setting are unknown., Materials and Methods: We evaluated 52 STEMI patients (56.6 ± 11 years, 88.5% male) treated with ICD in primary prevention who underwent echocardiography and CMR prior to ICD implantation. ICD implantation was indicated based on the presence of heart failure and depressed LVEF (≤ 35%) by echocardiography, CMR, or both. Prediction of ICD therapies (ICD-T) during follow-up by echocardiography and CMR before ICD implantation was assessed., Results: Compared to echocardiography, LVEF was lower by cardiac CMR (30.2 ± 9% vs. 37.4 ± 7.6%, p < 0.001). LVEF ≤ 35% was detected in 24 patients (46.2%) by Echo and in 42 (80.7%) by CMR. During a mean follow-up of 6.1 ± 4.2 years, 10 patients received appropriate ICD-T (3.16 ICD-T per 100 person-years): 5 direct shocks to treat very fast ventricular tachycardia or ventricular fibrillation, 3 effective antitachycardia pacing (ATP) for treatment of ventricular tachycardia, and 2 ineffective ATP followed by shock to treat ventricular tachycardia. Echo-LVEF ≤ 35% correctly predicted ICD-T in 4/10 (40%) patients and CMR-LVEF ≤ 35% in 10/10 (100%) patients. CMR-LVEF improved on Echo-LVEF for predicting ICD-T (area under the curve: 0.76 vs. 0.48, p = 0.04)., Conclusion: In STEMI patients treated with ICD, assessment of LVEF by CMR outperforms Echo-LVEF to predict the subsequent use of appropriate ICD therapies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Marcos-Garcés, Perez, Gavara, Lopez-Lereu, Monmeneu, Rios-Navarro, de Dios, Merenciano-González, Gabaldon-Pérez, Ferrero-De-Loma-Osorio, Martínez-Brotons, Bondanza, Sánchez-Gómez, Albiach, Nunez, Bayés-Genís, Chorro, Ruiz-Granell and Bodi.)

Background: Freezing rate of second-generation cryoballoon (CB) is a biophysical parameter that could assist pulmonary vein isolation. The aim of this study is to assess freezing rate (time to reach -30°C ([TT-30C]) as an early predictor of acute pulmonary vein isolation using the CB., Methods: Biophysical data from CB freeze applications within a multicenter, nation-wide CB ablation registry were gathered. Successful application (SA), was defined as achieving durable intraprocedural vein isolation. And SA with time to isolation under 60 s (SA-TTI<60) as achieving durable vein isolation in under 60 s. Logistic regressions were performed and predictive models were built for the data set., Results: 12,488 CB applications from 1,733 atrial fibrillation (AF) ablation procedures were included within 27 centers from a Spanish CB AF ablation registry. SA was achieved in 6,349 of 9,178 (69.2%) total freeze applications, and SA-TTI<60 was obtained in 2,673 of 4,784 (55.9%) freezes where electrogram monitoring was present. TT-30C was shorter in the SA group (33.4 ± 9.2 vs 39.3 ± 12.1 s; p < 0.001) and SA-TTI<60 group (31.8 ± 7.6 vs. 38.5 ± 11.5 s; p < 0.001). Also, a 10 s increase in TT-30C was associated with a 41% reduction in the odds for an SA (odds ratio [OR] 0.59; 95% confidence interval [CI] 0.56-0.63) and a 57% reduction in the odds for achieving SA-TTI<60 (OR 0.43; 95% CI 0.39-0.49), when corrected for electrogram visualization, vein position, and application order., Conclusions: Time to reach -30°C is an early predictor of the quality of a CB application and can be used to guide the ablation procedure even in the absence of electrogram monitoring.

Cryoablation is safe and effective for the treatment of atrial fibrillation (AF) in controlled clinical trials, but contemporary real-world usage and outcomes are limited. The Report of the Spanish Cryoballoon Ablation Registry (RECABA) was designed to evaluate acute and 12-month outcomes of cryoballoon ablation for the treatment of AF in Spain. Patients from 27 Spanish centers were prospectively enrolled. Patients were treated with cryoballoon ablation and managed according to standard of care protocols at each center. The primary endpoint was ≥ 30 s freedom from AF at 12-month after a 3-month blanking period. Secondary endpoints included a description of patient characteristics, cryoablation procedural strategy and safety, and predictors of efficacy. In total, 1742 patients (71.4% PAF, 68.8% male, mean age 58.02 ± 10.40 years, 76.1% overweight or obese, CHA 2 DS 2 -VASc index 1.40 ± 1.28) were enrolled. Patients received 7.2 ± 2.67 cryo-applications. PV potentials could be detected in 61% of the PVs during ablation, with a mean time to block of 52.9 ± 37.02 s. Acute PVI was observed in 97% of PVs with 75.8% isolated with the first cryo-application. Mean procedural time was 113 ± 41 min. Acute complications occurred in 4.4% of the cases. With follow-up in 1628 patients, AF-free survival was 78.5% (PAF: 80.6% vs PersAF 73.3%; p < 0.001). Left atrium enlargement, female sex, non-PAF, and early recurrence were independent predictors of AF recurrence (p < 0.05). RECABA provides detailed insight into current dosing practices and demonstrates cryoablation is safe and effective in real-world use.ClinicalTrials.gov number: NCT02785991., (© 2021. The Author(s).)

Electrocardiogram showing a regular wide QRS tachycardia with left branch block (LBBB) like in morphology at 200 beats per minute (bpm). During electrophysiology study, it suddenly gets narrow and faster. What is the mechanism of the switch from a broad complex to a narrow complex tachycardia?, Competing Interests: All authors had access to the data and a role in writing the manuscript., (© 2020 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)