Department of Internal Medicine, University of Tennessee Health Science Center, Memphis, TN.
Department of Internal Medicine, University of Tennessee Health Science Center, Memphis, TN.
Curr Probl Cardiol. 2022 Sep;47(9):100927. doi: 10.1016/j.cpcardiol.2021.100927. Epub 2021 Jul 3.
Sudden cardiac death is a major cause of cardiovascular mortality in the United States with 250,000-450,000 deaths annually. Transvenous Implantable Cardioverter-Defibrillator (ICD) has been conventionally used for both primary and secondary prevention of ventricular tachycardia or fibrillation (VT/VF). It is also associated with a high risk of complications like hemothorax, pneumothorax, cardiac tamponade, lead failure, and increased risk for infections. Subcutaneous ICD (S-ICD) poses as a viable alternative with reduced chances of complications. This manuscript aims to review S-ICD as an alternative to conventional transvenous ICD and its efficacy. We conducted a Medline search of "Subcutaneous," "ICD," "transvenous," and "ventricular tachycardia or fibrillation (VT/VF)" to identify pivotal trials published before June 2021, for inclusion in this review. Major practice guidelines, trial bibliographies, and pertinent reviews were examined to ensure the inclusion of relevant trials. The following section reviews data from pivotal trials to review the efficacy of S-ICD for the termination of VT/VF. The S- ICD system consists of a pulse generator positioned over the sixth rib between the midaxillary and anterior axillary line and a tripolar parasternal electrode with the proximal and distal sensing electrodes positioned adjacent to the xiphoid process and manubriosternal junction, respectively. The conversion of the efficacy of the S-ICD after the first shock ranges from 88%-90.1% and 98.2%-100% after 5 shocks based on the current evidence. The device also has a 99% complication-free rate at 180 days with no increased complications even in ESRD patients. The PRAETORIAN trial showed non-inferiority of the S-ICD to transvenous ICD concerning device-related complications or inappropriate shocks in patients. S-ICD has several advantages including no need for fluoroscopy for implantation, decreased risk of infections, complications, and evidence of safety even in high-risk populations like ESRD. The limitations include the inherent lack of pacing abnormalities, the increase in inappropriate shocks compared to transvenous ICD, and non-reliability if there are baseline T wave abnormalities, especially in the inferior leads. Thus, S-ICD can be considered as an alternative to transvenous ICD in patients with an indication for defibrillator therapy but with no indication for pacing.
心源性猝死是美国心血管死亡率的主要原因，每年有 25 万至 45 万人死亡。经静脉植入式心脏复律除颤器 (ICD) 通常用于室性心动过速或心室颤动 (VT/VF) 的一级和二级预防。它也与较高的并发症风险相关，如血胸、气胸、心脏压塞、导线故障以及感染风险增加。皮下 ICD (S-ICD) 作为一种可行的替代方法，并发症的风险较低。本文旨在回顾 S-ICD 作为传统经静脉 ICD 的替代方法及其疗效。我们对 Medline 进行了“Subcutaneous”、“ICD”、“transvenous”和“ventricular tachycardia or fibrillation (VT/VF)”的搜索，以确定 2021 年 6 月前发表的关键试验，纳入本综述。主要实践指南、试验书目和相关综述也进行了检查，以确保纳入相关试验。以下部分回顾了关键试验的数据，以回顾 S-ICD 终止 VT/VF 的疗效。S-ICD 系统由一个位于第六肋腋中线和前腋前线之间的脉冲发生器和一个三极胸骨旁电极组成，近端和远端感知电极分别位于剑突和胸骨柄交界处附近。根据目前的证据，S-ICD 在第一次电击后的转复效率范围为 88%-90.1%，在 5 次电击后的转复效率为 98.2%-100%。该设备在 180 天内的并发症发生率为 99%，无并发症，即使在 ESRD 患者中也没有增加并发症。PRAETORIAN 试验表明，在设备相关并发症或不适当电击方面，S-ICD 与经静脉 ICD 相比不劣效。S-ICD 具有许多优点，包括植入时无需透视、感染、并发症风险降低，甚至在 ESRD 等高危人群中也有安全性证据。其局限性包括缺乏起搏异常的固有缺陷、与经静脉 ICD 相比不适当电击增加，以及如果存在基线 T 波异常，特别是在 inferior leads 时，其不可靠性。因此，S-ICD 可考虑作为有指征进行除颤治疗但无起搏指征的患者的经静脉 ICD 的替代方法。
