Downloadable Algorithm to Reduce Inappropriate Shocks Caused by Fractures of Implantable Cardioverter-Defibrillator Leads

Abstract

Background-The primary method for monitoring implantable cardioverter-defibrillator lead integrity is periodic measurement of impedance. Sprint Fidelis leads are prone to pace-sense lead fractures, which commonly present as inappropriate shocks caused by oversensing. Methods and Results-We developed and tested an algorithm to enhance early identification of lead fractures and to reduce inappropriate shocks. This lead-integrity algorithm, which can be downloaded into presently implanted implantable cardioverter-defibrillators, alerts the patient and/or physician when triggered by either oversensing or excessive increases in impedance. To reduce inappropriate shocks, the lead-integrity algorithm increases the number of intervals to detect (NID) ventricular fibrillation when triggered. The lead-integrity algorithm was tested on data from 15 970 patients with Fidelis leads (including 121 with clinically diagnosed fractures) and 95 other fractured leads confirmed by analysis of returned product.

2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing

“…Excluding recalled leads, ventricular oversensing accounts for less than 10% of inappropriate shocks, but it often results in repetitive shocks and severe symptoms [82,[142][143][144]. Recently introduced features reduce inappropriate therapies from oversensing of physiologic T waves and nonphysiologic signals related to pace-sense lead failures as discussed below.…”

“…The present algorithms were developed to identify impending lead failures on recalled leads, notably the Sprint Fidelis. These algorithms might not be appropriate for detecting failures in other leads [144]. There is a high false-positive rate when using these algorithms, and caregivers must carefully review the device data that caused the alert to ensure the lead experienced a true failure [145].…”

“…Alerts that combine both oversensing and abrupt changes in impedance trends provide earlier warning of lead failure than a fixed impedance threshold [144,145,149]. Such alerts can be delivered via wireless remote monitoring and/or by notifying the patient via vibration or an audible tone.…”

“…Such alerts can be delivered via wireless remote monitoring and/or by notifying the patient via vibration or an audible tone. Caregivers must respond rapidly to alerts to minimize inappropriate shocks [144,149]. Wireless remote monitoring has been reported to reduce response time [150].…”

Use of remote monitoring in the management of system-related complications in implantable defibrillator patients

“…Patient-alert features have been implemented in ICDs for detection of system-related complications, for example acoustic alerts. Swerdlow et al [9] demonstrated that the Medtronic lead integrity alert algorithm triggered an acoustic alert of impending inappropriate shocks at least 3 days in advance in 76% of patients with lead failure. However, although these acoustic alerts are a useful tool facilitating early detection of system-related complications, they are insensitive and prone to falsepositive evaluations [10,11].…”