Implantable Heart Sound Filtering for Accurate EMAT Monitoring

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Solution Overview

Problem

Existing heart sound monitoring techniques struggle to obtain accurate heart sound data for diagnosing heart function, particularly in implantable medical devices, as they rely on conventional methods that are not efficient in capturing key heart sound characteristics.

Innovation Solution

An implantable medical device (IMD) equipped with a heart sound sensor and filtering assembly that utilizes multiple bandwidths to identify specific characteristics of heart sounds, allowing for selective filtering and improved detection of electromechanical activation time (EMAT) through a three-axis accelerometer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional heart sound monitoring techniques are used to monitor heart sound duration, amplitude, and intervals, then the monitoring system is simple to implement, but the accuracy of heart sound data for diagnosing heart function is insufficient

Engineering Contradiction:
Improveaccuracy of heart sound dataVSAvoidcomplexity of monitoring system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the heart sound signal analysis into multiple distinct parameters including duration, amplitude, intervals between peaks, and electromechanical activation time (EMAT). By dividing the monitoring function into these separable components, the system achieves comprehensive diagnostic accuracy while maintaining manageable system complexity through modular parameter detection

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of analysis by incorporating electromechanical activation time (EMAT) measurement alongside traditional heart sound parameters. This additional temporal dimension provides more comprehensive heart function diagnostics without requiring complete system redesign, thereby improving measurement precision while controlling complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If heart sounds are used to track proper or improper functioning of the heart for HF diagnostics, then diagnostic capability is improved, but obtaining accurate heart sound data remains difficult

Engineering Contradiction:
Improvediagnostic capabilityVSAvoidaccuracy of heart sound data
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs feedback mechanisms by continuously monitoring multiple heart sound parameters and comparing them against established diagnostic criteria. The system uses interval measurements between R-wave peaks and heart sound peaks to provide feedback on ventricular contraction timing, enabling reliable heart failure diagnostics through iterative data validation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the heart sound monitoring system multi-functional by enabling it to detect multiple cardiac parameters (duration, amplitude, intervals, EMAT) from a single sensor system. This universal approach improves diagnostic capability across different heart conditions while maintaining data accuracy through comprehensive parameter collection

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enhances the accuracy of heart sound data collection, enabling precise monitoring of heart function and electromechanical activation time, even in varying patient postures and device migration, thereby supporting more effective heart failure diagnostics.

Implementation Method 1

Miniaturized accelerometers have been proposed, that utilize microelectromechanical system (MEMS) technology, to detect heart sounds while the accelerometers are implanted within an IMD

Methodology Applied
Scientific EffectAccelerometer detection: Accelerometer

Implementation Method 2

a filtering assembly configured to filter the HS signals utilizing first and second bandwidths to output first and second bandwidth HS components

Methodology Applied
Scientific EffectSignal filtering: Filter (electronic)

Data Source

PatentEP4480394B1System for monitoring heart function based on electromechanical activation time
Publication Date: 2026.02.25 PACESETTER INC
  • EP4480394B1 patent drawingFigure 1
  • EP4480394B1 patent drawingFigure 2
  • EP4480394B1 patent drawingFigure 3A

AI summary

An implantable medical device (IMD) (100) that can include a HS sensor (270) configured to sense heart sound (HS) signals along an axis over a first period of time and a filtering assembly (404) configured to filter the HS signals utilizing first and second bandwidths to output first and second bandwidth HS components. The IMD (100) can also include one or more processors (220) that can be configured to identify a first characteristic of interest (COI) of a heartbeat from the first bandwidth HS component and identify a second COI of the heartbeat from the second bandwidth HS component. The one or more processors (220) can also be configured to select one of the first and second bandwidths based on a comparison of the first and second COI, obtain additional HS signals during a second period of time and utilize the one of the first and second bandwidths selected to filter the additional HS signals.