Experience in a Brazilian Center with Cryoablation for Electric Isolation of the Pulmonary Veins in Paroxysmal and Persistent Atrial Fibrillation – Preliminary Results in Brazil

Abstract Background Electrical isolation of the pulmonary veins is recognized as the cornerstone of non-pharmacological treatment of Atrial Fibrillation (AF), and therefore, has been recommended as the first step in AF ablation according to all guidelines. Even though the cryoballoon technology is widely used in North America and Europe, this experience is still incipient in many developing countries such as Brazil. Objective To evaluate initial results regarding success and safety of the new technology in patients with persistent and paroxysmal AF. Methods One hundred and eight consecutive patients with symptomatic AF refractory to pharmacological treatment were submitted to cryoablation for isolation of the pulmonary veins. Patients were separated into two groups according to AF classification: persistent (AF for over one week); or paroxysmal (shorter episodes). Recurrence and procedural safety data were analyzed respectively as primary and secondary outcomes. The level of significance was 5%. Results One hundred and eight patients, with mean age 58±13 years, 84 males (77.8%), underwent cryoablation. Sixty-five patients had paroxysmal AF (60.2%) and 43 had persistent AF (39.2%). The mean time of the procedure was 96.5±29.3 minutes and the mean fluoroscopy time was 29.6±11.1 minutes. Five (4.6%) complications were observed, none fatal. Considering a blanking period of 3 months, 21 recurrences (19.4%) were observed in a one-year follow-up period. The recurrence-free survival rates of AF in the paroxysmal and persistent groups were 89.2% and 67.4%, respectively. Conclusion Cryoablation for electrical isolation of the pulmonary veins is a safe and effective method for the treatment of AF. Our results are consistent with other studies suggesting that this technology can be used as an initial technique even in cases of persistent AF.

摘要 背景 肺静脉电隔离（pulmonary vein isolation）被认为是心房颤动（Atrial Fibrillation, AF）非药物治疗的基石，因此各类临床指南均将其列为房颤消融的首要步骤。尽管冷冻球囊技术（cryoballoon technology）在北美与欧洲已得到广泛应用，但在巴西等众多发展中国家，该技术的临床应用经验仍处于起步阶段。目的 评估该项新技术在阵发性房颤（paroxysmal AF）及持续性房颤（persistent AF）患者中应用的初始疗效与安全性。方法 连续纳入108例经药物治疗无效的症状性房颤患者，接受冷冻消融（cryoablation）以实现肺静脉电隔离。根据房颤分型将患者分为两组：持续性房颤（persistent AF）组（房颤持续时长超过1周）与阵发性房颤（paroxysmal AF）组（发作时长更短）。以术后复发情况与手术操作安全性数据分别作为主要结局与次要结局指标，检验水准设定为5%。结果 共纳入108例患者，平均年龄为58±13岁，其中男性84例（77.8%）。阵发性房颤患者65例（60.2%），持续性房颤患者43例（39.2%）。手术平均时长为96.5±29.3分钟，平均透视时长为29.6±11.1分钟。共观察到5例（4.6%）并发症，无死亡病例。以3个月为空白期（blanking period），在1年随访期内共观察到21例（19.4%）复发。阵发性房颤组与持续性房颤组的1年无复发生存率分别为89.2%与67.4%。结论 冷冻消融实现肺静脉电隔离是治疗房颤的安全有效手段。本研究结果与其他同类研究结论一致，表明该技术即便应用于持续性房颤患者，也可作为初始治疗方案。