Smidt Heart Center, Cedars Sinai Medical Center, Los Angeles, California, USA.
Medtronic plc, Mounds View, Minnesota, USA.
JACC Clin Electrophysiol. 2021 Nov;7(11):1387-1399. doi: 10.1016/j.jacep.2021.03.004. Epub 2021 Apr 28.
This study reports the sensing and arrhythmia detection performance of a novel extravascular (EV) implantable cardioverter-defibrillator (ICD) in a first-in-human pilot study.
The EV ICD lead is implanted in the substernal space, resulting in novel sensing and detection challenges. It uses a programmable sensing profile with new or modified discrimination of oversensing and of ventricular tachycardia (VT) from supraventricular tachycardia (SVT).
Electrograms were post-processed from induced ventricular fibrillation (VF) at implant to determine virtual detection times for each programmable sensitivity and the least-sensitive safe sensitivity setting. In ambulatory patients, programmed sensitivity provided at least a twofold safety margin for detecting induced VF. Noise discrimination was stress tested, and the effects of source, posture, and lead maturation were determined on electrogram amplitude. Telemetry Holter monitors were used to quantify undersensing and oversensing.
In 20 patients at implant, the least-sensitive safe sensitivity for VF detection ranged from 0.1 to 0.6 mV. Seventeen patients were followed up for a total of 16.6 patient-years. Electrogram amplitudes were stable over time, but there were significant differences among postures and sensing vectors. For the primary sensing vector, the weighted oversensing and undersensing rates were 1.03% and 0.40% respectively, on a beat-to-beat basis. Oversensing did not cause inappropriate therapy in patients with in situ leads. Oversensing discriminators withheld VF detection in 4 of 5 spontaneous, sustained oversensed episodes. SVT-VT discriminators correctly classified 93% of 128 sustained SVTs in monitor zones.
In the EV ICD pilot study, oversensing did not cause inappropriate therapy during ambulatory follow-up of stable leads.
本研究报告了一项新型血管外（EV）植入式心脏复律除颤器（ICD）在首例人体初步研究中的传感和心律失常检测性能。
EV ICD 导联植入胸骨后间隙，导致新型传感和检测挑战。它使用可编程的传感配置文件，对过感知和室性心动过速（VT）与室上性心动过速（SVT）进行新的或修改的区分。
从植入时诱发的心室颤动（VF）中对电图进行后处理，以确定每个可编程灵敏度和最不敏感的安全灵敏度设置的虚拟检测时间。在门诊患者中，为检测诱发的 VF，编程灵敏度提供了至少两倍的安全裕度。对噪声区分进行了压力测试，并确定了源、体位和导联成熟度对电图幅度的影响。遥测 Holter 监测器用于量化欠感知和过感知。
在 20 名植入患者中，VF 检测的最不敏感安全灵敏度范围为 0.1 至 0.6 mV。17 名患者总共随访了 16.6 年。随着时间的推移，电图幅度保持稳定，但在体位和传感向量之间存在显著差异。对于主要传感向量，在逐拍的基础上，加权过感知和欠感知率分别为 1.03%和 0.40%。过感知不会导致原位导联患者的不适当治疗。在 5 次自发持续过感知发作中，过感知鉴别器有 4 次阻止了 VF 检测。SVT-VT 鉴别器在监测区域正确分类了 93%的 128 次持续 SVT。
在 EV ICD 初步研究中，在稳定导联的门诊随访中，过感知不会导致不适当的治疗。
