Cardiac Pacing Control via Electromechanical Timing
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Solution Overview
Problem
Current cardiac pacing technologies for CHF patients lack accurate measures of metabolic demand and pumping efficiency, which hinders the effectiveness of cardiac resynchronization therapy.
Innovation Solution
The method involves detecting the timing relationship between electrical activation and mechanical cardiac activity using sensors to control therapies such as cardiac pacing, CRT, and ventricular assist, allowing for tailored treatment based on electromechanical timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rate adaptive pacemakers use body activity or breathing rate to estimate metabolic demand, then the pacing rate can be modified, but the measurement precision of metabolic demand and pumping efficiency is insufficient
Solution Approach 1:
The patent replaces mechanical sensors (accelerometers, piezoelectric sensors) with electrical field-based detection methods. The device detects mechanical cardiac activity by measuring changes in electrical impedance or electrogram morphology during the cardiac cycle, which are influenced by mechanical events like valve closure and wall motion. This substitution provides more precise measurement of pumping efficiency while avoiding the complexity and reliability issues of mechanical sensors in the harsh cardiac environment.
Solution Approach 2:
The patent uses electrical signals as an intermediary to detect mechanical cardiac activity. Instead of directly measuring mechanical parameters, the device detects changes in the electrical field caused by mechanical events (such as impedance changes during compression or electrogram waveform changes during valve closure). This intermediary approach enables precise indirect measurement of mechanical function through electrical parameters that are easier to measure reliably in the cardiac environment.
2Adaptability or versatility
If CRT uses multiple pacing leads to coordinate heart chambers, then pumping efficiency is improved, but the therapy cannot be accurately tailored to individual patient needs
Solution Approach 1:
The patent implements feedback control by continuously monitoring electromechanical timing parameters (such as the interval between electrical pacing stimulus and resulting mechanical contraction) and using this information to automatically adjust pacing parameters. The device measures the actual mechanical response to electrical stimulation and modifies pacing timing, amplitude, or sequence to optimize synchrony and pumping efficiency for each individual patient, thereby eliminating the loss of information about actual cardiac function.
3Reliability
If pacemakers monitor only electrical activity, then the device complexity is low, but the reliability of therapy control is insufficient
Solution Approach 1:
The patent makes the pacemaker multi-functional by enabling it to detect both electrical activity (through conventional electrogram sensing) and mechanical cardiac activity (through impedance changes or electrogram morphology analysis). The device uses the same electrical sensing circuitry to derive both electrical timing information and mechanical event information, eliminating the need for separate mechanical sensors. This universal approach improves reliability through comprehensive monitoring while avoiding the added complexity of dedicated mechanical detection systems.
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 synchrony and efficiency of heart function, enhances therapy efficacy, and monitors cardiac performance by adjusting therapy parameters based on electromechanical timing, thereby improving treatment outcomes for CHF patients.
Implementation Method 1
detecting electrical activation of a patient's heart
Implementation Method 2
detecting a change in ventricular impedance indicative of mechanical cardiac activity
Data Source
AI summary
Devices and methods for therapy control based on electromechanical timing involve detecting electrical activation of a patient's heart, and detecting mechanical cardiac activity resulting from the electrical activation. A timing relationship is determined between the electrical activation and the mechanical activity. A therapy is controlled based on the timing relationship. The therapy may improve intraventricular dyssynchrony of the patient's heart, or treat at least one of diastolic and systolic dysfunction and/or dyssynchrony of the patient's heart, for example. Electrical activation may be detected by sensing delivery of an electrical stimulation pulse to the heart or sensing intrinsic depolarization of the patient's heart. Mechanical activity may be detected by sensing heart sounds, a change in one or more of left ventricular impedance, ventricular pressure, right ventricular pressure, left atrial pressure, right atrial pressure, systemic arterial pressure and pulmonary artery pressure.