Lead Integrity Alert Is Useful for Assessment of Performance of Biotronik Linox Leads.

INTRODUCTION: Medtronic's Lead Integrity Alert (LIA) software algorithm is useful for detecting abnormal parameters across various ICD-lead families. However, its utility in the assessment of the Biotronik Linox™ family of high-voltage (HV) leads is unknown. METHODS: We conducted a retrospective cohort study to assess the performance of the LIA algorithm to detect abnormalities and lead failure in Linox ICD-leads. All LIA-enabled Medtronic devices connected to an active Linox lead were included. The alerts were adjudicated by 2 blinded electrophysiologists and correlated with clinical data. RESULTS: Between 2008 and 2012, data from 208 patients with 564 patient-years of follow-up were available for analysis. The median follow-up duration was 32 (IQR 21-41 months). Twenty-one LIA triggers were noted in 20 different patients. The median delay until a positive LIA was 32 months (IQR 21-41 months) postimplant with a 5-year lead survival free from LIA of 76%. Ninety-five percent (19/20) LIA alerts were true lead failures. The most common LIA triggers were short V-V intervals (85%) and nonsustained ventricular tachycardia (85%). Abrupt changes of the ICD-lead impedance occurred in 5/20 triggers. Inappropriate ICD-shocks were strongly associated with a positive LIA (30% vs. 7.4%; P = 0.006). Of the explanted Linox leads 53% had visible abnormalities. The sensitivity, specificity, and positive predictive value for lead failure in the presence of a LIA trigger were 87%, 99.5%, and 95.2%, respectively. CONCLUSIONS: A positive LIA trigger in Biotronik Linox ICD-leads is highly predictive of lead failure. LIA is useful in ongoing surveillance of lead performance.

Lead Integrity Alert Triggered by T-wave Oversensing.

T-wave oversensing (TWOS) is a relatively common occurrence in pacemakers and defibrillators that can lead to pauses and inappropriate implantable cardioverter-defibrillator shocks. We present a case of TWOS that triggered the Lead Integrity Alert (Medtronic, Minneapolis, MN, USA) without evidence of actual lead failure.

Management of Elevated Therapeutic Impedances on Deep Brain Stimulation Leads.

CLINICAL VIGNETTE: A 64-year-old male with a history of essential tremor with bilateral thalamic ventralis intermedius deep brain stimulation implants had elevated therapeutic impedance values despite normal lead integrity impedances and good response to stimulation. CLINICAL DILEMMA: Do elevated therapeutic impedance values indicate a sign of hardware malfunction? What are the guidelines to approach deep brain stimulation hardware malfunction? CLINICAL SOLUTION: Lead integrity impedance values are a better evaluation of hardware integrity. The discrepancy between therapeutic and lead-integrity impedance values can arise when using low voltage settings. GAPS IN KNOWLEDGE: There are no established guidelines for the management of possible hardware malfunction in deep brain stimulation. The recommended approach is to distinguish between open and short circuit problems followed by an "inching" evaluation, assessing the structures from the implantable and programmable generator to the intracranial leads. Constant-current devices will deliver a more stable stimulation but the effect of their adoption is still not clear. EXPERT COMMENTARY: This case emphasizes the need for clinicians to understand fundamental differences in lead integrity and therapeutic impedance while utilizing a methodical approach in treating hardware malfunction. It highlights future avenues of investigation regarding the utility of constant current DBS technology.

Myopotential oversensing notified by Lead Integrity Alert in a patient with implantable cardioverter defibrillator with a dedicated bipolar epicardial sensing lead.

Although myopotential oversensing by a dedicated bipolar lead is rare, an epicardial lead on a dilated ventricle might contribute to its sensitivity. Myopotential oversensing was notified by the Lead Integrity Alert in this case. We should be aware of this possibility for the management of such patients.