Department of Cardiology, Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, Calif., USA.
Circulation. 2010 Oct 12;122(15):1449-55. doi: 10.1161/CIRCULATIONAHA.110.962407. Epub 2010 Sep 27.
Downloadable software upgrades are common in consumer electronics but not in implantable medical devices. Fractures of implantable cardioverter-defibrillator (ICD) leads present commonly as inappropriate shocks. A lead-integrity alert (LIA) designed to reduce inappropriate shocks is the first software download approved to enhance nominally functioning, previously implanted ICDs.
We performed a prospective study to determine whether an LIA could reduce inappropriate shocks. Patients were included if they had ICD lead fractures confirmed by analysis of explanted leads. The LIA group included the first 213 patients who met the inclusion criteria after the LIA was approved who had the LIA downloaded. The LIA is triggered either by high impedance or rapid oversensing. It responds by delaying detection of ventricular fibrillation and initiating a patient alert every 4 hours. The control group included the first 213 patients who did not have the LIA downloaded. They were monitored by conventional daily impedance measurements that respond with a daily alert. The LIA group had a 46% relative reduction (95% confidence interval 34% to 55%) in the percentage of patients with ≥1 inappropriate shock (LIA 38% versus control 70%, P<0.001) and a 50% relative reduction (95% confidence interval 33% to 61%) in the percentage with ≥5 shocks (25% versus 50%, P<0.001). The LIA group also had a higher percentage of patients who either did not receive a shock or had ≥3 days of warning before the shock (72% versus 50%, P<0.001).
A software download that upgrades previously implanted ICDs without surgical revision reduces inappropriate shocks caused by lead fractures.
可下载软件升级在消费电子产品中很常见，但在植入式医疗设备中却并非如此。植入式心律转复除颤器（ICD）导线的断裂通常表现为不适当的电击。一种旨在减少不适当电击的导线完整性警报（LIA）是第一种经批准用于增强名义上正常、先前植入的 ICD 的软件下载。
我们进行了一项前瞻性研究，以确定 LIA 是否可以减少不适当的电击。如果通过对取出的导线进行分析确认 ICD 导线断裂，则患者符合纳入标准。LIA 组包括在 LIA 获得批准后符合纳入标准的前 213 名患者，这些患者下载了 LIA。LIA 由高阻抗或快速过感知触发。它的反应是延迟检测心室颤动，并每 4 小时启动一次患者警报。对照组包括前 213 名未下载 LIA 的患者。他们通过常规的每日阻抗测量进行监测，该测量会在每天发出警报。LIA 组的≥1 次不适当电击（LIA 组 38%，对照组 70%，P<0.001）和≥5 次电击（LIA 组 25%，对照组 50%，P<0.001）的患者比例分别降低了 46%（95%置信区间为 34%至 55%）和 50%（95%置信区间为 33%至 61%）。LIA 组也有更高比例的患者没有接受电击或在电击前有≥3 天的预警（LIA 组 72%，对照组 50%，P<0.001）。
无需手术修正即可对先前植入的 ICD 进行软件升级的下载可减少因导线断裂引起的不适当电击。
