Semmelweis University, Heart and Vascular Center, 68, Varosmajor Street, H-1122 Budapest, Hungary.
Department of Cardiology, Christchurch Hospital, PO Box 4345, Christchurch, New Zealand.
Europace. 2022 May 3;24(5):762-773. doi: 10.1093/europace/euab243.
The aim of this study is to provide a thorough, quantified assessment of the substernal space as the site of extravascular implantable cardioverter-defibrillator (ICD) lead placement using computed tomography (CT) scans and summarizing adverse events and defibrillation efficacy across anatomical findings. Subcutaneous ICDs are an alternative to transvenous defibrillators but have limitations related to ICD lead distance from the heart. An alternative extravascular system with substernal lead placement has the potential to provide defibrillation at lower energy and pacing therapies from a single device.
A multi-centre, non-randomized, retrospective analysis of 45 patient CT scans quantitatively and qualitatively assessing bony, cardiac, vascular, and other organ structures from two human clinical studies with substernal lead placement. Univariate logistic regression was used to evaluate 15 anatomical parameters for impact on defibrillation outcome and adjusted for multiple comparisons. Adverse events were summarized. Substernal implantation was attempted or completed in 45 patients. Defibrillation testing was successful in 37 of 41 subjects (90%) using ≥10 J safety margin. There were two intra-procedural adverse events in one patient, including reaction to anaesthesia and an episode of transient atrial fibrillation during ventricular fibrillation induction. Anatomical factors associated with defibrillation failure included large rib cage width, myocardium extending very posteriorly, and a low heart position in the chest (P-values <0.05), though not significant adjusting for multiple comparisons.
Retrospective analysis demonstrates the ability to implant within the substernal space with low intra-procedural adverse events and high defibrillation efficacy despite a wide range of anatomical variability.
本研究旨在通过计算机断层扫描（CT）对胸骨后间隙进行全面、量化的评估，以评估血管外植入式心律转复除颤器（ICD）导线的位置，并总结解剖学发现的不良事件和除颤效果。皮下 ICD 是经静脉除颤器的替代方法，但与 ICD 导线与心脏的距离有关，存在局限性。胸骨后导联的替代血管外系统有可能提供更低能量的除颤和来自单个设备的起搏治疗。
对 45 名患者的 CT 扫描进行了多中心、非随机、回顾性分析，从两个胸骨后导联的人体临床研究中对骨骼、心脏、血管和其他器官结构进行了定性和定量评估。使用单变量逻辑回归评估了 15 个解剖参数对除颤结果的影响，并进行了多次比较调整。总结了不良事件。45 名患者尝试或完成了胸骨下植入。使用≥10 J 的安全裕度，对 41 名受试者中的 37 名（90%）进行了成功的除颤测试。一名患者发生了两起术中不良事件，包括对麻醉的反应和心室颤动诱导期间短暂心房颤动发作。与除颤失败相关的解剖因素包括胸廓宽度大、心肌非常向后延伸以及心脏在胸部的位置较低（P 值<0.05），但多次比较调整后无显著意义。
尽管存在广泛的解剖学变异性，但回顾性分析表明胸骨后空间内植入的能力，其术中不良事件发生率低，除颤效果高。
