ECG Wavelet Transform for False VT Alarm Suppression

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Solution Overview

Problem

Current methods for reducing false alarms in patient monitors, particularly ventricular tachycardia (VT) alarms, are inefficient and often require additional physiological waveforms, making them unsuitable for settings outside intensive care units (ICUs) and computationally intensive.

Innovation Solution

A method using a multiresolution wavelet transform on ECG waveform data to reduce dimensionality and extract features from the wavelet transform, analyzing variability among leads to differentiate between true and false VT alarms, without requiring additional waveforms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional physiological waveforms (ABP, PPG, CVP, PAP) are used to reduce false alarms, then false alarm suppression rate improves, but device complexity and computational requirements increase

Engineering Contradiction:
Improvefalse alarm suppression rateVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes only the ECG waveform signal, separating it from other physiological parameters (ABP, PPG, CVP, PAP) that were previously required. This extraction approach maintains false alarm suppression capability while eliminating the complexity of integrating and processing multiple additional waveform sources.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the ECG signal through wavelet transform, changing its representation from time-domain to time-frequency domain. This parameter transformation enables effective false alarm detection using only ECG data, replacing the need for multiple physiological parameters with a transformed version of a single parameter.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If nonlinear joint dynamical models and Bayesian filters are used for false alarm detection, then measurement precision improves, but computational intensity increases

Engineering Contradiction:
Improvealarm detection accuracyVSAvoidcomputational intensity
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent replaces complex nonlinear joint dynamical models and Bayesian filters with a wavelet transform-based approach. This substitution maintains measurement precision for alarm detection while dramatically reducing computational intensity, making the system feasible for real-time implementation on standard medical equipment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent segments the ECG signal into different frequency components through wavelet transform, analyzing specific frequency bands (such as 0.5-40 Hz for QRS complexes) to detect arrhythmias. This segmentation approach achieves high detection accuracy by focusing computational resources on diagnostically relevant signal portions rather than processing the entire signal spectrum.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If spectral decomposition of local signal segments is performed, then measurement precision improves, but loss of time increases

Engineering Contradiction:
Improvesignal quality assessmentVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies wavelet transform in a periodic, sliding-window manner across the ECG signal, continuously analyzing segments of fixed duration (e.g., 10-second windows with overlapping segments). This periodic processing approach maintains measurement precision for signal quality assessment while optimizing processing time by reusing computations from previous windows and focusing only on new data portions.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS10357169B2Methods for determining whether patient monitor alarms are true or false based on a multi resolution wavelet transform and inter-leads variability
Publication Date: 2019.07.23 RGT UNIV OF CALIFORNIA
  • US10357169B2 patent drawing
  • US10357169B2 patent drawing
  • US10357169B2 patent drawing

AI summary

Methods for automatically determining whether a patient monitor alarm will sound from a true or false signal, in particular from ventricular tachycardia (VT) and suppressing false alarms without eliminating any true alarms are presented. A multiresolution wavelet is extracted from a raw ECG waveform. Features are then extracted from the wavelets that account for summary statistics, noise, areas under the curve and summary statistics of the KL-divergence of the power spectra density between every two ECG leads. A classifier can be then be trained and its performance measured.