[Types of pathomorphological changes in the heart caused by cardiostimulating electrodes]

Area of Science:

• Cardiovascular Pathology
• Medical Device Research

Context:

• Pacemaker implantation is a common procedure for managing cardiac arrhythmias.
• Understanding the long-term tissue response to implanted electrodes is crucial for patient safety and device efficacy.

Purpose:

• To investigate the morphological and histological reactions at pacemaker electrode implantation sites.
• To classify and characterize tissue changes occurring around endocardial pacemaker electrodes.

Summary:

• Post-mortem examination of 18 patients revealed common endocardial changes, including connective tissue bridging and tricuspid valve alterations.
• Myocardial reactions such as electrode penetration and sub-tip changes were also observed, occurring independently or in combination.
• Connective-tissue organizing wall thrombi facilitated electrode fixation to the endocardium in 97% of cases.
• No direct correlation was found between implantation duration and the extent of connective tissue bridging.
• Exceptional cases showed myocardial softening or scarring under normally positioned electrodes, particularly in patients with myocarditis.

Impact:

• Provides detailed insights into the tissue-device interactions of pacemaker electrodes.
• Informs the development of improved pacemaker lead designs and implantation techniques.
• Contributes to the understanding of potential complications associated with long-term pacemaker use.