Dual-Sensor Pacemaker Activity Detection

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Solution Overview

Problem

Current pacemakers face challenges in accurately adjusting heart rate based on activity levels due to limitations in accelerometer and temperature sensor technologies, which can lead to inappropriate pacing rate control, such as misinterpreting motion or failing to detect activity without corresponding temperature changes.

Innovation Solution

An implantable system that combines a temperature sensor and a motion sensor to detect the onset of patient activity, where the temperature sensor initially detects activity and the motion sensor confirms or rejects this detection, allowing for precise adjustment of pacing rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an accelerometer is used to detect patient activity, then the pacemaker can respond to motion, but it may inappropriately increase pacing rate due to misinterpreting non-activity motion

Engineering Contradiction:

Improvepacemaker response speedVSAvoidpacing rate control accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent combines an accelerometer and a temperature sensor into a dual-sensor system. The accelerometer detects motion while the temperature sensor detects physiological temperature changes. By merging these two sensing modalities, the system achieves more reliable activity detection - the pacemaker only increases pacing rate when both sensors confirm activity, thereby reducing false positives from non-activity motion while maintaining rapid response capability.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If a temperature sensor is used to detect patient activity, then the pacemaker can detect metabolic changes, but it may falsely signal activity during temperature changes without actual activity

Engineering Contradiction:

Improveactivity detection accuracyVSAvoidpacing rate control reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system uses bidirectional feedback between the temperature sensor and accelerometer. When the temperature sensor detects a temperature change indicative of activity, it triggers the accelerometer to verify whether actual physical motion is occurring. Conversely, when the accelerometer detects motion, it can trigger the temperature sensor to confirm metabolic activity. This cross-verification feedback mechanism eliminates false signals from both non-activity temperature changes and activity without metabolic response.

Inventive Principle:

Principle #23Feedback

3Reliability

If both temperature sensor and motion sensor are continuously activated, then activity detection is more accurate, but energy consumption increases

Engineering Contradiction:

Improveactivity detection reliabilityVSAvoidbattery power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic sampling of sensor data rather than continuous monitoring. The controller periodically activates the temperature sensor and accelerometer at scheduled intervals to check for activity conditions. When no activity is detected, sensors remain in a low-power state. This periodic action maintains reliable activity detection capability while dramatically reducing average power consumption compared to continuous sensor operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses the accelerometer as a preliminary sensor to detect motion before activating the more power-intensive temperature sensor. When the accelerometer detects motion, it preliminarily indicates possible activity, triggering the temperature sensor to perform a more detailed metabolic assessment. This preliminary action by the lower-power accelerometer filters out unnecessary temperature sensor activations, reducing overall energy consumption while maintaining detection reliability.

Inventive Principle:

Principle #10Preliminary action

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 provides more accurate and reliable heart rate adjustments by confirming activity through both temperature and motion changes, reducing inappropriate pacing rate control and improving cardiac response.

Implementation Method 1

A rise in a person's core blood temperature (often first preceded by a small dip in the core blood temperature) is typically observed at the onset of activity

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 2

an accelerometer that can detect motion (and more specifically, acceleration) as a proxy for activity

Methodology Applied

Scientific EffectAccelerometer detection: Accelerometer

Data Source

PatentUS11717692B2Pacemaker systems and methods using multiple sensors for rate response pacing

Publication Date: 2023.08.08 PACESETTER INC

AI summary

Certain embodiments of the present technology disclosed herein relate to implantable systems, and methods for use therewith, that use a temperature sensor to initially detect an onset of patient activity, and then use a motion sensor to confirm or reject the initial detection of the onset of patient activity. Other embodiments of the present technology disclosed herein relate to implantable systems, and methods for use therewith, that use a motion sensor to initially detect an onset of patient activity, and then use a temperature sensor to confirm or reject the initial detection of the onset of patient activity. The use of both a motion sensor and a temperature sensor provides improvements over using just one of the types of sensors for rate responsive pacing.