Preventing Overdiagnosis of Implantable Cardioverter-Defibrillator Lead Fractures Using Device Diagnostics

Abstract

An algorithm using only ICD diagnostics identifies leads with oversensing or high impedance as fractures or connection problems with a high degree of accuracy.

Implantable Cardioverter-Defibrillator Leads

“…Typical nonphysiological fracture electrograms validated by analysis of explanted leads have 5 subjective characteristics ( Figure 3) 25 : They always have (1) high frequency and (2) occur intermittently. In true bipolar leads, (3) they are not recorded on the shock channel.…”

“…A few fractured cable filaments may generate nonphysiological signals without measurable 26 and 15% of clinically diagnosed Riata failures. 22 Abrupt relative changes in impedance are more specific than absolute measurements, which record out-of-range values for gradual changes at the electrode-myocardial interface, 25 but a single abrupt change can be spurious. Pacing impedance <200 Ω is thought to indicate an insulation breach, but evidence is limited ( Figure 5).…”

“…The chest radiograph is important primarily for the exclusion of alternative diagnoses such as dislodgement with or without perforation and incomplete insertion of connector pins into the header 25 ( Figure IV in the online-only Data Supplement). The latter may require spot films or intraoperative radiographs.…”

“…Accurate diagnosis is important because other conditions can cause both abnormal impedance and oversensing, 25 and overdiagnosis results in unnecessary lead replacements. Table 1 summarizes the differential diagnosis.…”

Almanac 2013: cardiac arrhythmias and pacing

“…Strategies to reduce ICD complications and inappropriate shocks include using special diagnostic ICD algorithms to identify potential lead problems early (126), and changes in ICD programming with a prolonged delay in therapy for tachyarrhythmias of ≥200 beats/min or higher, as demonstrated in the MADIT-RIT (MADIT-Reduction in Inappropriate Therapy) trial (127). Increasing clinical experience is also being gained in the use of subcutaneous ICDs (128,129), which holds great potential in reducing some types of ICD related complications, although an initial learning curve needs to be overcome first.…”