Cardiac Event Detection Modulated by Accelerometer Posture Data

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Solution Overview

Problem

Current medical devices struggle to accurately detect cardiac arrhythmias and deliver timely therapy, particularly in situations where patients experience falls or significant posture changes during cardiac events, as these changes can complicate the detection and response to cardiac episodes.

Innovation Solution

The implementation of a medical device system that utilizes accelerometer signals to determine falls, slumping postures, or changes in posture associated with cardiac events, allowing for modulated responses such as altered therapy delivery and alert prioritization, thereby enhancing the detection and treatment of cardiac arrhythmias.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If accelerometer signals are used to detect falls and posture changes during cardiac events, then the sensitivity and specificity of cardiac event detection is improved, but the device complexity increases

Engineering Contradiction:
Improvecardiac event detection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing functions (cardiac rhythm monitoring and motion/posture detection) into a single integrated medical device system. The accelerometer is integrated with the cardiac monitoring device to simultaneously detect both cardiac events and patient posture/falls, eliminating the need for separate devices and improving detection accuracy through correlated data analysis.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The medical device is designed to perform multiple functions: traditional cardiac rhythm monitoring, detection of falls, detection of posture changes, and differentiation between cardiac-related and non-cardiac-related events. This multi-functionality allows the device to provide comprehensive patient monitoring while improving the specificity of cardiac event detection by ruling out non-cardiac causes.

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

2Reliability

If therapy delivery is modulated based on posture and fall detection, then the appropriateness and timeliness of therapy is improved, but the control system complexity increases

Engineering Contradiction:
Improvetherapy delivery appropriatenessVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The therapy delivery system dynamically adjusts its response based on real-time detection of patient posture and fall events. The control system transitions between different therapy modes depending on the detected state: delivering full therapy for cardiac events occurring in upright posture, modifying or withholding therapy for events during falls or inappropriate postures, and providing alerts rather than immediate therapy when falls are detected without confirmed cardiac arrhythmia.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback loops where accelerometer data continuously informs cardiac event detection and therapy delivery decisions. The control system analyzes the temporal relationship between posture changes and cardiac events, using this feedback to determine whether detected arrhythmias are likely cardiac in origin or secondary to physical movement, thereby optimizing therapy appropriateness.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If contextual data from accelerometer signals is collected and analyzed, then the specificity of cardiac episode detection is improved, but the processing requirements and energy consumption increase

Engineering Contradiction:
Improvecardiac episode detection specificityVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system applies partial processing of accelerometer data by focusing analysis only on specific parameters relevant to cardiac event differentiation (such as sudden posture changes, fall patterns, and temporal correlation with cardiac events) rather than comprehensive gait analysis. This selective approach reduces computational burden and energy consumption while maintaining sufficient specificity for cardiac episode detection.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system changes the parameters of data processing by adjusting the sensitivity and analysis depth based on the detected state. During periods of normal activity, minimal processing is applied. When cardiac events are detected, the system intensifies analysis of accelerometer patterns to determine causality. This dynamic parameter adjustment optimizes energy usage while maintaining detection specificity.

Inventive Principle:
Principle #35Parameter changes

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 improves the sensitivity and specificity of cardiac event detection and therapy delivery, leading to better patient outcomes by collecting contextual data on falls and posture changes, enabling more timely and accurate interventions.

Implementation Method 1

Such implantable and/or external devices may include an accelerometer. Accelerometer signal(s) may be used to determine a falling event or a posture of a patient.

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Data Source

PatentUS20230309861A1Motion sensor-modulated cardiac episode detection and/or alerting
Publication Date: 2023.10.05 MEDTRONIC INC
  • US20230309861A1 patent drawing
  • US20230309861A1 patent drawing
  • US20230309861A1 patent drawing

AI summary

An example medical device system includes memory configured to store information relating to an occurrence of a cardiac event in a patient and processing circuitry configured to determine the occurrence of the cardiac event in the patient. The processing circuitry is configured to determine at least one of a fall of the patient, a slumping posture of the patient, or a change from an upright posture to a non-upright posture of the patient and that the cardiac event is associated therewith in time. The processing circuitry is configured to, in response to determining that the cardiac event and the at least one of the fall of the patient, the slumping posture of the patient, or the change from the upright posture to the non-upright posture of the patient are associated in time, modulate a response to the cardiac event.