Cardiac Pacing Site Selection Using Electrical and Acoustic Signals
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Solution Overview
Problem
Current medical devices face challenges in optimizing pacing therapy delivery to the heart, as selecting the appropriate pacing site is crucial for effectiveness and efficiency, but existing methods often fail to confirm tissue viability, leading to ineffective activation of myocardial tissue.
Innovation Solution
A system that includes a cardiac signal sensing circuit, a stimulus circuit, and a control circuit to determine intrinsic ventricular activation time intervals and heart sound characteristics, which identifies candidate pacing sites and assesses tissue viability by delivering pacing stimuli and quantifying mechanical cardiac contraction, thereby selecting the most effective pacing site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing therapy is delivered to multiple potential sites, then the likelihood of finding an effective site increases, but the complexity of device operation and treatment time increases
Solution Approach 1:
The device performs preliminary assessment of multiple pacing sites by delivering test stimuli and measuring evoked responses before final site selection. This preliminary action identifies viable sites in advance, ensuring therapy effectiveness while simplifying the final deployment decision.
Solution Approach 2:
The device automatically evaluates multiple pacing sites through self-testing mechanisms, where the implanted device itself performs the assessment by delivering stimuli and measuring responses without requiring external intervention. This resolves the contradiction by making the complex evaluation process autonomous.
2Measurement precision
If pacing stimuli are delivered to assess tissue viability, then accurate site selection is achieved, but energy consumption increases and battery life decreases
Solution Approach 1:
The device delivers partial assessment stimuli at multiple sites rather than exhaustive testing at all potential sites. By performing limited evaluations at each location and selecting candidates based on preliminary results, the device achieves sufficient measurement precision while consuming less energy than complete assessment of all sites would require.
Solution Approach 2:
Preliminary rapid assessment of multiple sites is performed first to identify viable candidates, followed by more detailed evaluation only at selected sites. This staged approach reduces total energy consumption while maintaining adequate measurement precision for clinical decision-making.
3Reliability
If comprehensive evaluation of pacing sites is performed, then optimal hemodynamic function is achieved, but treatment time and device complexity increase
Solution Approach 1:
The device performs preliminary evaluation of multiple pacing sites by delivering test stimuli and measuring evoked cardiac mechanical activity in advance. This preliminary action identifies promising sites quickly, allowing optimal hemodynamic function to be achieved without requiring exhaustive evaluation of all possible sites during the clinical procedure.
Solution Approach 2:
The device uses feedback from measured evoked responses (such as heart sound changes or mechanical activity detection) to rapidly assess pacing site effectiveness. This feedback mechanism enables quick elimination of non-viable sites and identification of optimal sites, reducing treatment time while maintaining comprehensive evaluation quality.
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 optimizes pacing therapy by ensuring delivery at the most viable site, improving hemodynamic function and reducing unnecessary stress on the heart while prolonging battery life in implantable devices.
Implementation Method 1
a cardiac signal sensing circuit that senses a plurality of intrinsic cardiac signals using a plurality of cardiac pacing sites
Implementation Method 2
a stimulus circuit that provides an electrical cardiac pacing stimulus to the plurality of pacing sites
Implementation Method 3
a heart sound sensing circuit that produces a paced heart sound signal representative of mechanical cardiac activity
Data Source
AI summary
An apparatus comprises a cardiac signal sensing circuit configured to sense a plurality of intrinsic cardiac signals using a plurality of cardiac pacing sites, a heart sound sensing circuit, a stimulus circuit configured to provide an electrical cardiac pacing stimulus to the plurality of pacing sites, and a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit. The control circuit includes a pacing site locating circuit configured to generate an indication of a preferred pacing site as one of a) a subset of the respective cardiac pacing sites selected using the intrinsic ventricular activation time interval value, from which subset the preferred pacing site is selected using the heart sound characteristic value; or b) a subset of the respective cardiac pacing sites selected using the heart sound characteristic value, from which subset the preferred pacing site is selected using the ventricular activation time interval value.