Cardiac Lead Shielding via Outer Conductive Member Dissipation
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Solution Overview
Problem
Implantable medical devices (IMDs) face challenges in shielding cardiac lead systems from radio frequency (RF) energy, particularly during procedures like MRI, which can induce currents and thermal energy, leading to potential heating and malfunctions.
Innovation Solution
The implementation of a cardiac lead system with a multilumen member and outer conductive members, including a first and second electrode with varying surface areas, where the first electrode is positioned to dissipate induced currents through a larger surface area, thereby reducing heat generation and shielding the inner conductors from RF energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cardiac lead system is exposed to RF energy during MRI procedures, then the lead can perform its therapeutic function, but induced currents and thermal energy are generated causing potential heating and malfunctions
Solution Approach 1:
An outer conductive member (shield) is introduced as an intermediary between the RF energy environment and the inner conductors. This shield intercepts induced currents before they can flow through the inner conductors, preventing harmful thermal energy generation while allowing the lead to function during MRI procedures
2Temperature
If the first electrode has a larger surface area to dissipate induced currents, then heat generation is reduced, but the device complexity increases
Solution Approach 1:
The electrode with the larger surface area is strategically positioned at the proximal end of the lead where induced currents are most intense. This localized approach concentrates the heat dissipation capability where it is most needed, reducing overall thermal energy generation without requiring all electrodes to be enlarged
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces the induction of currents and thermal energy in IMDs, preventing heating and ensuring the safe operation of cardiac lead systems during exposure to external energy fields like MRI, thus enhancing the reliability and safety of IMDs.
Implementation Method 1
reducing heat generation and shielding the inner conductors from RF energy
Implementation Method 2
Portions of the IMD may act as an antenna and have current and thermal energy induced therein due to the MRI procedure
Data Source
AI summary
An implantable medical device (IMD) can include a cardiac pacemaker or an implantable cardioverter-defibrillator (ICD). Various portions of the IMD, such as a device body, a lead body, or a lead tip, can be provided to reduce or dissipate a current and heat induced by various external environmental factors. According to various embodiments, features can be incorporated into the lead body, the lead tip, or the IMD body to reduce the creation of an induced current, or dissipate the induced current and heat created due to an induced current in the lead. For example, an IMD can include at least one outer conductive member and a first electrode. The first electrode can be in electrical communication with the at least one outer conductive member. The first electrode can dissipate a current induced in the at least one outer conductive member via a first portion of the anatomical structure.