Leadless Cardiac Stimulation via Frequency-Tuned AM Receivers
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Solution Overview
Problem
Conventional cardiac resynchronization therapy (CRT) leads are prone to mechanical stress, bacterial entry, thrombogenicity, and complications such as tricuspid regurgitation, limiting their effectiveness and safety for multisite heart stimulation.
Innovation Solution
A leadless cardiac stimulation system using AM transmitters and receivers with controllable frequency output signals, implanted at specific positions within the heart, to generate demodulated output signals that stimulate cardiac tissue at optimal times during the cardiac cycle, promoting improved cardiac performance without the risks associated with traditional leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing leads are used for cardiac resynchronization therapy, then effective multisite heart stimulation can be achieved, but the leads are subject to mechanical stress and fracture
Solution Approach 1:
The patent removes the lead component from the system entirely, replacing it with a leadless generator that implants a receiver device directly in the heart tissue. This extraction of the lead eliminates the mechanical stress and fracture issues while maintaining the ability to deliver pacing signals to multiple sites.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the external transmitter and the implanted receiver. The transmitter sends RF signals through the body, which are then received and converted to pacing signals by the implanted device, eliminating the need for physical lead connections.
2Reliability
If pacing leads are used for cardiac resynchronization therapy, then effective multisite heart stimulation can be achieved, but the leads can serve as a conduit for bacterial entry to the blood pool
Solution Approach 1:
By removing the lead from the system and using a leadless generator implanted directly in the heart, the patent eliminates the conduit that bacteria could use to enter the blood pool, thereby reducing infection risk.
3Reliability
If pacing leads are used for cardiac resynchronization therapy, then effective multisite heart stimulation can be achieved, but the leads are inherently thrombogenic and elicit fibrotic reactions
Solution Approach 1:
The patent removes the lead component that causes thrombogenicity and fibrotic reactions, replacing it with a leadless generator that minimizes tissue interaction and foreign body response.
4Reliability
If pacing leads are used for cardiac resynchronization therapy, then effective multisite heart stimulation can be achieved, but the leads can impinge on leaflet motion and cause significant tricuspid regurgitation
Solution Approach 1:
By removing the lead from the system and using a leadless generator implanted in the heart tissue, the patent eliminates the lead's ability to impinge on valve leaflet motion and cause tricuspid regurgitation.
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 system effectively synchronizes heart contractions, reducing the risk of arrhythmia and lead-related complications, while providing greater opportunities for LV pacing site selection and improved CRT response.
Implementation Method 1
AM transmitter having a controllable output frequency. The AM transmitter is configured to generate a first-frequency output signal in response to a first control signal and to generate a second-frequency output signal in response to a second control signal
Implementation Method 2
The first AM receiver is configured to (a) generate a first demodulated output signal that is capable of stimulating cardiac tissue when the first-frequency output signal arrives at the first antenna
Data Source
AI summary
Synchronized stimulation of cardiac tissue can be implemented by implanting two or more rectifier-based AM receivers into different positions within a subject's heart. Each receiver is tuned to a different frequency, and generates an output signal that is capable of stimulating cardiac tissue when a signal at the corresponding tuned frequency arrives at the receiver. An AM transmitter can activate any given one of the receivers by transmitting a signal into the subject's body at the proper frequency. A controller controls the transmitter by commanding the transmitter to transmit pulses of AC at different frequencies at different times, so that when those pulses are received by the correspondingly-tuned receivers, each of the receivers will generate respective output signals that stimulate respective parts of the heart at respective times to promote improved cardiac performance.