R-spike Amplifier for S-ICD R-wave Signal Enhancement
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Solution Overview
Problem
Current subcutaneous implantable cardioverter-defibrillators (S-ICDs) lack pacing capabilities, are large due to high power requirements, and face challenges with subcutaneous electrocardiogram signal recording, leading to delayed or absent life-supporting therapy in ventricular fibrillation detection.
Innovation Solution
An implantable cardiac system with an R-spike amplifier that enhances the R-wave to T-wave signal-to-noise ratio, allowing for reliable S-ICD rhythm classification and reduced detection times for ventricular fibrillation by amplifying R-wave signals, even in disturbed signal conditions, using a leadless or leaded cardiac pacemaker communicatively coupled with an S-ICD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If subcutaneous ECG signal recording is used in S-ICD, then the device can detect ventricular arrhythmias, but the signal quality is poor and susceptible to interference leading to delayed therapy
Solution Approach 1:
The patent introduces an intermediary device (the implantable pulse generator with amplifier) that mediates between the weak cardiac electrical signals and the S-ICD detection system. The amplifier acts as a signal booster that enhances the R-wave amplitude before transmission to the S-ICD, thereby improving signal quality without requiring changes to the S-ICD hardware itself
Solution Approach 2:
The patent changes the amplitude parameter of the R-wave signal through electronic amplification. By increasing the R-wave amplitude to a higher level, the signal-to-noise ratio is improved, making the cardiac signals more distinguishable from interference and enabling reliable detection by the S-ICD system
2Measurement precision
If R-wave amplitude is increased through amplification, then S-ICD rhythm classification reliability is improved, but energy consumption increases
Solution Approach 1:
The amplifier is activated periodically rather than continuously - specifically during the R-wave detection window. This periodic operation mode allows the system to achieve the necessary signal amplification only when needed for rhythm classification, thereby reducing overall energy consumption compared to continuous amplification
Solution Approach 2:
The amplification is applied selectively to enhance only the critical R-wave portion of the ECG signal that is necessary for rhythm classification, rather than amplifying the entire ECG waveform continuously. This partial action approach minimizes energy expenditure while achieving the required detection accuracy
3Measurement precision
If detection time is extended to improve signal quality, then measurement accuracy improves, but therapy delay increases
Solution Approach 1:
The amplifier is pre-configured and ready to operate before the actual detection event occurs. The signal amplification pathway is established in advance, allowing immediate enhancement of R-waves when they appear, thereby enabling fast detection without requiring extended observation periods to accumulate sufficient signal quality
Data Source
AI summary
An implantable cardiac system that includes an implantable cardiac pacemaker or leadless pacemaker (iLP) and a second device such as a subcutaneous implantable cardioverter-defibrillator (S-ICD). The pacemaker includes an R-spike amplifier that amplifies stimulated ventricle excitations or R-waves to increase R-wave to T-wave signal to noise ratio and to improve indirect detection of ventricular rhythm classification by the S-ICD. The S-ICD includes an electrode line for defibrillation, a sensing unit and a stimulation detection unit. The S-ICD records a subcutaneous electrocardiogram between shock electrode poles and provides potentially life-saving therapy based thereon. The system significantly increases the specificity and sensitivity of an S-ICD in combination with an implanted cardiac pacemaker or iLP having an R-spike amplifier.