"In-line" bipolar, steroid-eluting, high impedance, epimyocardial pacing lead

Area of Science:

• Biomedical Engineering
• Cardiovascular Device Technology
• Implantable Electronic Devices

Background:

• Traditional pacing leads face limitations, creating differences between endocardial and epicardial approaches.
• Epicardial pacing offers direct left ventricular access, crucial when transvenous methods are unsuitable.
• Advanced lead designs are essential to enhance epicardial pacing efficacy and reliability.

Purpose of the Study:

• To evaluate the chronic performance and safety of a novel bipolar epimyocardial pacing lead.
• To assess pacing and sensing capabilities, impedance, and capture thresholds over a 6-month period.
• To compare explant findings with initial implant values.

Main Methods:

• Implantation of 12 bipolar epimyocardial leads (Medtronic model 10389) in six immature canines.
• Weekly monitoring of pacing and sensing parameters for 6 months.
• Analysis of lead impedance, voltage thresholds, and histological tissue response at explant.

Main Results:

• No significant changes in sensed R waves or R wave slew rates were observed between implant and explant.
• Consistently high lead impedances were maintained: bipolar (1658 ± 331 Ω) and unipolar (1327 ± 308 Ω).
• Chronic voltage thresholds remained low and stable, with negligible fibrous reaction at the electrode-tissue interface.

Conclusions:

• The evaluated bipolar epimyocardial lead demonstrates stable chronic pacing with high impedance and low thresholds.
• The "in-line" design and single suture technique facilitate easier implantation.
• This lead represents a significant advancement for optimizing epicardial pacing capabilities.