Inductive Coil Layout for Recharging Insertable Cardiac Monitors

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Solution Overview

Problem

Conventional subcutaneous implantable cardiac monitors (ICMs) face challenges in accurately capturing low-amplitude P-waves due to limited electrode size, inter-electrode spacing, and signal processing, leading to inadequate diagnosis of heart rhythm disorders, and require frequent recharging without causing patient discomfort or harm.

Innovation Solution

A subcutaneous insertable cardiac monitor (ICM) with an internal energy harvesting module and optimized electrode placement and configuration, using overlapping inductive coils for efficient energy transfer, enabling long-term monitoring and high-fidelity P-wave capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional subcutaneous ICMs use small electrodes with limited inter-electrode spacing, then the device size is reduced and implantation is easier, but P-wave detection accuracy deteriorates

Engineering Contradiction:
Improvedevice sizeVSAvoidP-wave detection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent transitions from planar electrode arrangements to a three-dimensional configuration where electrodes are positioned at different depths and angles within the subcutaneous space. This dimensional expansion allows adequate inter-electrode spacing for P-wave detection while maintaining a compact overall device footprint suitable for subcutaneous implantation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The electrode assembly is nested within the ICM housing structure, with electrodes positioned in a compact nested arrangement that maximizes spacing between sensing elements while keeping the overall device volume small. The electrodes are integrated into the housing cavity in a space-efficient manner.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Duration of action of moving object

If the ICM battery capacity is increased to extend monitoring duration, then the monitoring duration is improved, but the device size and implantation complexity increase

Engineering Contradiction:
Improvemonitoring durationVSAvoiddevice size
Core Design Contradiction:
Duration of action of moving objectVSVolume of moving object

Solution Approach 1:

The patent employs low-power electronic components and optimizes power consumption parameters across all device subsystems. The microprocessor operates in low-power modes, sensors are activated only when needed, and communication protocols are optimized for minimal energy usage, thereby extending battery life without increasing capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The device uses periodic sampling of physiological parameters rather than continuous monitoring, with the microprocessor entering sleep modes between measurement cycles. This periodic operation pattern significantly reduces average power consumption while maintaining adequate monitoring coverage.

Inventive Principle:
Principle #19Periodic action

3Duration of action of moving object

If the ICM is recharged frequently through external coils, then the monitoring duration is maintained, but patient discomfort and potential harm increase

Engineering Contradiction:
Improvemonitoring durationVSAvoidpatient discomfort and harm
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The ICM incorporates an internal energy harvesting module that automatically generates electrical energy from the patient's body movements and physiological processes. This self-charging mechanism eliminates the need for frequent external recharging, reducing patient discomfort and eliminating associated risks while maintaining continuous operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The device includes a large-capacity battery installed during the initial implantation procedure, providing sufficient energy reserves for extended monitoring periods. This preliminary energy provisioning reduces the frequency of recharging interventions needed throughout the monitoring duration.

Inventive Principle:
Principle #10Preliminary action

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

The ICM provides extended, reliable monitoring and improved P-wave detection, enhancing arrhythmia diagnosis and reducing the need for surgical interventions by optimizing energy harvesting and electrode placement.

Implementation Method 1

Each of the overlapping inductive coils configured to generate alternating current, at least a portion of which is used to power the electronic circuitry, upon being exposed to a magnetic field generated by a transmitting coil located outside the living body

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4026485B1System for induction-based subcutaneous insertable physiological monitor recharging
Publication Date: 2026.03.04 BARDY DIAGNOSTICS INC
  • EP4026485B1 patent drawingFigure 1
  • EP4026485B1 patent drawingFigure 2~4
  • EP4026485B1 patent drawingFigure 5~6

AI summary

An insertable cardiac monitor (ICM) with induction-based recharging capabilities and a transmitting coil for recharging the same are disclosed. The length of the monitoring performed by the ICM is extended and the functionality of the ICM enhanced, by including an internal energy harvesting module that allows for charging the ICM at a high speed without burning the patient or overheating components of the ICM. Internally, the energy harvesting module includes at least two overlapping receiving coils that are spaced to be orthogonal to each other and that have a tilt angle of substantially 45°. Such overlapping wire combination allows to minimize mutual inductance of the solenoid coils and increase the rate at which energy can be provided to the energy harvesting module. Further, the rate at which the energy is transmitted from the outside can be increased by defining in a transmitting coil a substantially triangular gap.