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Electrical dysfunction associated with conductor externalization of a silicone left ventricular lead
G Stuart Mendenhall1, Samir Saba
1University of Pittsburgh, Department of Cardiac Electrophysiology, Pittsburgh, Pennsylvania.
Pacing and Clinical Electrophysiology : PACE
|January 14, 2015
Summary
The St. Jude Medical QuickFlex LV lead advisory highlights potential insulation failure. This can cause impedance drops and capture threshold changes, requiring careful monitoring of lead performance.
Area of Science:
- Cardiovascular device engineering
- Implantable electronic devices
Background:
- The St. Jude Medical QuickFlex LV lead family is under manufacturer advisory due to insulation failures.
- Previous reports noted outer insulation failure and conductor externalization without electrical parameter changes.
Purpose of the Study:
- To report a specific case of St. Jude Medical QuickFlex LV lead failure.
- To investigate the relationship between conductor externalization and electrical parameter changes.
Main Methods:
- Physical examination of the lead to confirm conductor externalization.
- Electrical performance testing, including impedance and capture threshold measurements.
- Saline bath testing to assess lead resistance changes.
Main Results:
- A sudden drop in impedance and rise in capture threshold of the left ventricular ring electrode were observed.
- Conductor externalization was confirmed on physical examination.
- Saline bath testing demonstrated a reproducible, transient reduction in lead resistance linked to externalization.
Conclusions:
- Conductor externalization in QuickFlex LV leads can lead to significant changes in electrical performance.
- Mechanical forces like flexion and torsion may contribute to lead failure.
- Close monitoring of the electrical performance of this lead family is crucial.
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