Failure of impedance monitoring to prevent adverse clinical events caused by fracture of a recalled high-voltage implantable cardioverter-defibrillator lead

Downloadable Software Algorithm Reduces Inappropriate Shocks Caused by Implantable Cardioverter-Defibrillator Lead Fractures

“…1,20 Despite alerts based on impedance, inappropriate shocks are the most common presentation of lead failures. [2][3][4][5][6][7][8] The rationale for a lead failure diagnostic that incorporates oversensing in addition to impedance is that oversensing is the causal antecedent of inappropriate shocks. A fracture may generate sufficient oversensing to cause inappropriate shocks either without an impedance increase or with an impedance increase in the interval between daily impedance measurements.…”

“…1 Fractures of pace-sense conductors in defibrillation leads may cause an oversensing of nonphysiological potentials that results in inappropriate detection of ventricular fibrillation (VF) and shocks. [2][3][4][5][6][7][8] Despite alerts based on high impedance, fractures commonly present with clusters of inappropriate shocks. [2][3][4][5] Fractures have been reported to cause loss of pacing, failure of defibrillation, or fatal proarrhythmia.…”

“…[2][3][4][5][6][7][8] Despite alerts based on high impedance, fractures commonly present with clusters of inappropriate shocks. [2][3][4][5] Fractures have been reported to cause loss of pacing, failure of defibrillation, or fatal proarrhythmia. 9 To reduce inappropriate shocks, we developed a lead-integrity alert (LIA) triggered by either oversensing or high impedance 5,10 that can be downloaded into previously implanted ICDs.…”

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

“…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]. Prevailing delayed leadrelated complications such as lead fracture and insulation defect are directly related to the lead impedance.…”

“…The diagnosis of lead-related complications may be challenging and cannot be solely based on impedance changes [11]. In case of lead fractures, alerts triggered by out-of-range impedances are one step beyond as the fracture has already occurred.…”