High impedance alert with safety switching: An unreported hazard of hybrid pacing systems

Abstract

Several Boston Scientific pacemaker models have a known issue with intermittent oversensing of the minute ventilation sensor when paired with non-Boston Scientific leads. Several of our patients with these hybrid systems have had transient out of range impedances and oversensing after safety switching which we suspected may be related. A retrospective analysis of 395 patients who had pacemakers implanted between 2015-2017 found that transient out of range impedances with safety switching was present in 9% of Boston Scientific pacemakers paired with Abbott or Medtronic leads compared with 0% in other device-lead combinations (P = 0.0089).We postulate that the root cause of the minute ventilation oversensing and transient high impedance issue is the same, a header-lead interaction from low-level incompatibility. Recognizing this issue is critical to prevent unnecessary lead revisions or extractions as it can be prevented with a simple reprogramming of lead pace/sense configuration.

High Impedance Alerts with Pulse Generator -- Lead Mismatch

“…1,2,4 Recently, a large study of "hybrid" pacing systems incorporating Boston Scientific pacemakers and mismatched leads demonstrated a 9% rate of transient impedance increases. 3 To our best knowledge, our study is the largest series of Boston Scientific pulse generators with mismatched leads in the literature and confirms that there is a significant increase in occurrence of transient impedance increases with mismatched systems compared to matched systems.…”

“…The incidence of the primary outcome in our series is numerically lower than that reported in Karnik et al (3.4% vs. 9%). 3 Part of this difference may be the result of differences in the proportion of lead manufacturers used between the two studies. Our study included a much higher number of Medtronic leads compared to Karnik et al (332 vs. 18) and will therefore more accurately reflect the true incidence of the primary outcome with this lead-pulse generator combination.…”

“…Recently, case series have reported transient, episodic high-impedance alerts in Boston Scientific CIEDs when implanted with competitor leads. [1][2][3][4] As described in these case series, this results in a safety switch to unipolar sensing and pacing of the affected lead, which can result in lead noise and pacing suppression. Our study sought to investigate the incidence of spontaneous high-impedance events in matched vs. mismatched Boston Scientific CIED systems.…”

Lead-generator incompatibility with complete heart block—Double whammy: Device troubleshooting

“…Based on case series in the literature, safety switch owing to transient high impedances occurs in 9% of Boston Scientific pacemakers connected to Medtronic leads, but affects only 1 lead per patient. 2 , 3 Our case is unique, as this was exhibited in both RA and RV leads (a finding that is rare, occurred regardless of the software update, and has never been described before). We subsequently reprogrammed his device to a bipolar sensing/unipolar pacing configuration, thereby eliminating the ring electrode from the pacing circuit and preventing the safety switch ( Figure 3 ; no more noise on RA and RV channel).…”

Examining the Need to Standardize Implanted Stimulator Connectors: NANS Survey Results

“…The evolution of each type of implant increased connector complexity as well as incompatibility among products. The problem escalated when cardiac pacing devices added sensing functions, which became unreliable in the event of lead-IPG connector problems, leading to failed arrhythmia detection and potential life-threatening conditions (9,14,15). The same dilemma arises when discussing lead and IPG compatibility issues with neural devices destined for dependency on sensing to improve therapy output.…”