Implantable Device Mechanical Dyssynchrony Detection
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Solution Overview
Problem
Current implantable medical devices, such as pacemakers and ICDs, are unable to effectively detect and automatically adjust for mechanical dyssynchrony in the heart, which is crucial for improving cardiac output in patients with heart failure, as they primarily rely on electrical synchrony assessments that do not translate to mechanical synchrony.
Innovation Solution
The implementation of a method using cardiogenic impedance signals detected along different sensing vectors within the heart to measure mechanical dyssynchrony, allowing for the identification of abnormally contracting segments and adjustment of pacing parameters to reduce mechanical dyssynchrony, thereby improving hemodynamic output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical synchrony assessments are used to evaluate cardiac function, then the evaluation can be performed using existing electrical sensing capabilities, but the assessment does not translate to mechanical synchrony and fails to detect mechanical dyssynchrony
Solution Approach 1:
The patent replaces electrical sensing with mechanical sensing by using impedance cardiography to detect mechanical ventricular contraction. The system measures changes in thoracic impedance during the cardiac cycle, which reflect mechanical volume changes and contraction dynamics, thereby obtaining direct mechanical synchrony information rather than inferring it from electrical signals.
Solution Approach 2:
The patent introduces impedance signals as an intermediary between electrical activity and mechanical function. By measuring impedance changes during the cardiac cycle, the system creates a bridge that translates electrical sensing capabilities into mechanical function assessment, allowing detection of mechanical dyssynchrony without requiring direct mechanical sensors.
2Measurement precision
If multiple impedance vectors are used to detect mechanical dyssynchrony, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent divides the sensing system into multiple discrete impedance vectors, each measuring mechanical function in a specific direction or region. By segmenting the overall mechanical assessment into separate vector measurements, the system can analyze dyssynchrony patterns across different ventricular segments while maintaining manageable complexity through standardized measurement protocols.
Solution Approach 2:
The patent makes the impedance sensing system multi-functional by using the same basic sensing infrastructure to detect multiple types of cardiac information including mechanical synchrony, ventricular contraction dynamics, and dyssynchrony patterns. This universal approach allows a single device configuration to serve multiple diagnostic purposes without proportionally increasing complexity.
3Productivity
If automatic adjustment of pacing parameters is implemented based on mechanical dyssynchrony, then cardiac output improves, but the system requires real-time processing capability
Solution Approach 1:
The patent performs preliminary analysis of impedance signals to identify dyssynchrony patterns and determine optimal pacing parameters before actual pacing delivery. By pre-processing the mechanical function data and establishing guidance parameters in advance, the system reduces the computational burden during real-time pacing adjustment, lowering energy consumption while maintaining productivity benefits.
Solution Approach 2:
The patent implements a feedback loop where mechanical dyssynchrony detection continuously informs pacing parameter adjustment. The system measures impedance changes during the cardiac cycle, compares them against reference patterns to identify dyssynchrony, and automatically adjusts pacing parameters accordingly. This closed-loop feedback enables real-time optimization of cardiac output while using efficient comparison algorithms to minimize processing energy.
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 enables the detection and automatic adjustment of pacing parameters to reduce mechanical dyssynchrony, leading to improved cardiac output and timely responses to changes in heart function, such as those due to heart failure progression or conduction defects.
Implementation Method 1
a measure of mechanical dyssynchrony is detected in the heart of the patient based on a comparison of the set of cardiogenic impedance signals
Data Source
AI summary
Techniques are provided for evaluating mechanical dyssynchrony within the heart of patient in which a pacemaker, implantable cardioverter-defibrillator (ICD) or other medical device is implanted. In one example, a set of cardiogenic impedance signals are detected along different sensing vectors passing through the heart of the patient, particularly vectors passing through the ventricular myocardium. A measure of mechanical dyssynchrony is detected based on differences, if any, among the cardiogenic impedance signals detected along the different vectors. In particular, differences in peak magnitude delay times, peak velocity delay times, peak magnitudes, and waveform integrals of the cardiogenic impedance signals are quantified and compared to detect abnormally contracting segments, if any, within the heart of the patient. Warnings are generated upon detection of any significant increase in mechanical dyssynchrony. Diagnostic information is recorded for clinical review. Pacing therapies such as cardiac resynchronization therapy (CRT) can be activated or controlled in response to mechanical dyssynchrony to improve the hemodynamic output of the heart.