Isolation Ground Coupling for IC-ECG Power Line Noise Reduction
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Solution Overview
Problem
Existing medical systems face challenges in suppressing power line noise during the acquisition of intra-cardiac electrocardiogram (IC-ECG) signals due to electrical leakage imbalances between different subsystems, particularly when multiple systems are electrically coupled via a patient's body, leading to distorted measurements.
Innovation Solution
A low-impedance path is established to directly connect the system grounds of multiple medical systems, utilizing a safety capacitor and optionally an RF choke to bypass leakage currents through the patient's body, thereby reducing power line noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple medical systems are electrically coupled via a patient's body, then the systems can perform multiple functions (EP sensing and RF ablation), but power line noise and leakage current imbalances distort the measured signals
Solution Approach 1:
A dedicated low-impedance return path is introduced as an intermediary element between the isolated grounds of multiple medical systems. This return path acts as a mediator that provides a controlled route for leakage currents, preventing them from creating potential gradients on the patient's body that would otherwise distort EP signals. The return path includes safety capacitors and optionally RF chokes to manage different frequency components of the leakage currents.
Solution Approach 2:
The invention establishes equipotential connections between the isolated grounds of multiple medical systems through the low-impedance return path. By providing a direct conductive path between ground references, the system minimizes potential differences (gradients) that would otherwise appear on the patient's body and interfere with sensitive EP measurements. This creates an equipotential environment for the patient relative to the multiple system grounds.
2Reliability
If isolation barriers are used in medical systems, then patient safety is improved, but leakage current imbalances create potential gradients that cannot be rejected by reference measurements
Solution Approach 1:
The low-impedance return path serves as an intermediary that bridges the isolated ground systems while maintaining safety isolation barriers. Instead of removing the isolation barriers (which would compromise safety), the invention introduces this intermediate return path that provides a controlled route for leakage currents, preventing them from creating interfering potential gradients on the patient's body.
Solution Approach 2:
The return path establishes equipotential relationships between isolated ground systems, ensuring that potential gradients caused by leakage current imbalances do not appear on the patient. This allows the isolation barriers to remain in place for safety while eliminating their harmful side effect of creating measurement-interfering potential differences.
3Object-affected harmful factors
If a low-impedance path is added to connect system grounds, then power line noise is reduced, but device complexity increases
Solution Approach 1:
The low-impedance return path is designed to serve multiple functions simultaneously: it provides a leakage current return path, establishes equipotential relationships between isolated grounds, filters power line frequency noise (with safety capacitors), and attenuates RF interference (with optional RF chokes). This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in overall system complexity.
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 approach effectively suppresses power line noise, enhancing the quality of EP diagnostics signals such as ECGs by canceling potential gradients and improving measurement accuracy.
Implementation Method 1
utilizing a safety capacitor and optionally an RF choke to bypass leakage currents
Implementation Method 2
A low-impedance path is established to directly connect the system grounds of multiple medical systems, causing one or more leakage currents to flow via the low impedance path instead of via the patient
Data Source
AI summary
An apparatus includes two or more medical systems and a low impedance path. The two or more medical systems have respective electrical outputs and respective separate isolation grounds each isolated from power lines and from earth ground, wherein the two or more medical systems are electrically coupled one with the other via the patient. The low impedance path connects the separate isolation grounds of the medical systems to one another, causing one or more leakage currents to flow via the low impedance path instead of via the patient.