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Gross and microscopic pathological changes associated with nonthoracotomy implantable defibrillator leads
A E Epstein1, G N Kay, V J Plumb
1Division of Cardiovascular Disease, Department of Medicine, University of Alabama, Birmingham, AL, USA aepstein@uab.edu
Circulation
|October 14, 1998
Summary
Endocardial implantable cardioverter-defibrillator (ICD) leads cause significant fibrosis at the electrode-myocardial interface. This fibrosis may contribute to altered defibrillation thresholds and challenges with lead extraction in ICD systems.
Area of Science:
- Cardiology
- Pathology
- Biomedical Engineering
Background:
- Epicardial implantable cardioverter-defibrillator (ICD) lead effects are known, but endocardial lead impacts are less understood.
- This study investigates the gross and microscopic tissue changes from endocardial ICD leads in humans.
Purpose of the Study:
- To describe the gross and microscopic pathological changes associated with endocardial ICD leads.
- To characterize the electrode-myocardial interface in patients with endocardial ICDs.
Main Methods:
- Examination of 8 human hearts with endocardial ICD leads.
- Analysis of electrode-myocardial interfaces, surrounding myocardium, and valves.
- Histopathological assessment of tissue changes, including fibrosis and cell injury.
Main Results:
- Consistent intense endocardial fibrosis and fibroelastic tissue encasing each lead.
- Myocardial fibrosis adjacent to leads and tricuspid valve involvement in 5 patients.
- Microscopic interstitial fibrosis along shock paths; acute cell injury only in recently shocked hearts.
Conclusions:
- The ICD electrode-myocardial interface shows intense fibrosis.
- Fibrosis and defibrillation damage may affect defibrillation/pacing thresholds and lead extraction.
- Findings highlight the tissue response to endocardial ICD leads.