Pacemaker Hemodynamic Assessment Using Signal Segmentation
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Solution Overview
Problem
In pacemaker patients, the accurate acquisition and identification of heart sounds are often obscured by phrenic nerve stimulation caused by vigorous pacemaker ventricular pacing pulses, leading to confusion in heart-sound diagnostic algorithms and inaccurate hemodynamic assessments.
Innovation Solution
A system and methodology that collect and process ECG-electrical and heart-sound acoustic signals, using a blanking window to prevent pacemaker-induced phrenic nerve stimulation artifacts from interfering with heart-sound analysis, and provide real-time feedback for adjusting pacemaker operations to improve hemodynamic status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vigorous pacemaker ventricular pacing pulses are used, then cardiac resynchronization therapy effectiveness is improved, but phrenic nerve stimulation artifacts are generated that obscure heart-sound information
Solution Approach 1:
The patent divides the cardiac cycle into distinct phases (atrial contraction, ventricular contraction, etc.) and segments the signal processing accordingly. By analyzing ECG and phonocardiogram signals in separate temporal segments, the system can identify heart sounds during periods when phrenic nerve stimulation artifacts are least likely to occur, thereby maintaining assessment accuracy while using vigorous pacing pulses.
Solution Approach 2:
The system performs preliminary analysis of ECG signals to predict the timing of ventricular contraction and subsequent heart sounds. By anticipating when heart sounds will occur relative to pacing pulses, the system can pre-configure the phonocardiogram analysis parameters to focus on the optimal time windows for sound detection, avoiding artifact-contaminated periods.
2Measurement precision
If phrenic nerve stimulation artifacts are present in heart-sound signals, then diagnostic algorithm accuracy is reduced, but the artifacts provide no useful hemodynamic information
Solution Approach 1:
The patent extracts and isolates the phrenic nerve stimulation artifacts from the phonocardiogram signals using signal processing techniques. By identifying and removing these artifact components, the system preserves the useful heart-sound information that would otherwise be obscured, thereby maintaining measurement precision without losing diagnostic information.
Solution Approach 2:
The system introduces an intermediary signal processing layer that acts as a filter between the raw phonocardiogram signals and the diagnostic analysis. This intermediary processing stage uses ECG-derived timing information to selectively enhance heart sound signals while suppressing phrenic nerve stimulation artifacts, thereby improving measurement precision while preserving useful information.
3Productivity
If real-time hemodynamic assessment is performed, then feedback control for pacemaker adjustment is enabled, but signal processing complexity increases
Solution Approach 1:
The patent designs a multi-functional signal processing system where the same ECG and phonocardiogram analysis circuitry serves multiple purposes: real-time heart sound detection, hemodynamic status assessment, and feedback control for pacemaker adjustment. By making the processing system universal and multi-functional, the patent achieves high productivity in feedback control without proportionally increasing device complexity.
Solution Approach 2:
The system implements feedback control by continuously monitoring hemodynamic parameters derived from ECG and phonocardiogram signals and using this information to automatically adjust pacemaker settings. The feedback loop operates in real-time, with the processed information immediately influencing pacemaker operation, thereby achieving high responsiveness without requiring overly complex processing circuitry.
Data Source
AI summary
A method for gathering, creating and utilizing signal-processed ECG and acoustic signals for assessing, via presenting a highly intuitive, multi-component, common-time-base, real-time output display of selected (1) timing, (2) relative timing, and (3) other significant heart-behavioral elements relevant to such an assessment, a pacemaker patient's hemodynamic condition. The method offers an important option and capability for automatic, and/or manual, medical-treatment and/or pacemaker-control feedback, in real time, to improve a pacemaker patient's hemodynamic status, with such a patient's resulting hemodynamic-behavioral/status changes caused by such feedback being viewable immediately in the invention's produced output display.