The subcutaneous implantable cardioverter defibrillator (S-ICD) is an alternative to the transvenous implantable cardioverter defibrillator for the prevention of sudden cardiac death. Here, we report a rare case of refractoriness to an S-ICD after frequent therapies for ventricular fibrillation (VF) storms. A 24-year-old man underwent a bout of syncope with vomiting and incontinence at home. He was brought to the emergency room and was witnessed to spontaneously go into VF successfully converted by external defibrillation. Previously, he was diagnosed with a type I Brugada electrocardiogram pattern by a pilsicainide administration test in another hospital. Although he had a family history of sudden cardiac death in 3 relatives, including his brother, he was followed closely without any therapies because he had never had an episode of syncope. He was implanted with an S-ICD without any trouble. Seven months later, frequent S-ICD shocks for VF storms occurred. His VF was controlled by using intravenous amiodarone, which was converted to an oral preparation. However, his VF recurred after another 2 months. The analysis of his S-ICD data revealed that 4 consecutive shock deliveries could not terminate his VF and the final shock delivered could fortunately terminate it because of a high defibrillation threshold test (DFT) due to an increasing shock impedance (64 to 90 Ω). First, we performed an epicardial Brugada syndrome ablation and subsequently replaced and repositioned the S-ICD lead from a left to a right parasternal site. After the re-implantation of the S-ICD, the DFT test improved to within normal range. According to the pathological analysis, infiltration of inflammatory cells and extensive fibrosis were confirmed in the subcutaneous tissue around the shock lead and S-ICD body. Frequent S-ICD shocks for VF storms might cause various pathological changes around the device and lead to a high DFT.

中文翻译：

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在Brugada综合征病例中，频繁治疗心室纤颤风暴后皮下植入式心脏复律除颤器的顽固性

皮下植入式心脏复律除颤器（S-ICD）是静脉植入式心脏复律除颤器的替代产品，可防止心脏猝死。在这里，我们报告了罕见的心室纤颤（VF）风暴治疗后S-ICD难治性病例。一名24岁男子在家中出现晕厥，伴有呕吐和尿失禁。他被带到急诊室，并被目击自发地通过体外除颤转换成VF。此前，他在另一家医院通过比西卡尼德给药试验被诊断出患有I型Brugada心电图。尽管他有3名亲戚（包括他的兄弟）有心脏性猝死的家族病史，但由于他从未发生过晕厥发作，因此没有进行任何治疗就对其进行了密切跟踪。他没有任何麻烦地植入了S-ICD。七个月后，频繁发生S-ICD的VF风暴。通过静脉内胺碘酮控制他的室颤，将其转换为口服制剂。然而，他的室颤又过了两个月。对他的S-ICD数据的分析显示，连续4次电击无法终止他的VF，而且由于电击阻抗增加（64至90Ω），因此除颤阈值测试（DFT）高，最后一次电击可以终止它的VF。 。首先，我们进行了心外膜Brugada综合征消融术，随后替换并重新定位了S-ICD导联从左至右胸骨旁部位。重新植入S-ICD后，DFT测试改善到正常范围。根据病理分析，在电击导线和S-ICD体周围的皮下组织中确认了炎性细胞的浸润和广泛的纤维化。频繁的VF风暴S-ICD电击可能会导致设备周围发生各种病理变化，并导致DFT升高。