Ventricular Pacing Autonomic Tone Monitoring
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Solution Overview
Problem
Hemodynamic intolerance to ventricular pacing, which can lead to ventricular dyssynchrony and heart failure, is unpredictable and difficult to recognize due to nonspecific symptoms that overlap with other conditions, making it challenging to determine when patients are intolerant to ventricular pacing.
Innovation Solution
A method and system that assesses autonomic tone by comparing changes in parameters indicative of autonomic tone during periods of ventricular pacing and without pacing, using sensors and processors in implantable medical devices to determine the level of change and select appropriate pacing modes or intervals, thereby identifying hemodynamic intolerance and adjusting therapy accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ventricular pacing is delivered to treat cardiac dysfunction, then cardiac rhythm is controlled, but hemodynamic intolerance occurs leading to ventricular dyssynchrony and heart failure
Solution Approach 1:
The system continuously monitors heart rate variability during ventricular pacing and uses this feedback to detect hemodynamic intolerance. When changes in HRV indicate intolerance, the system automatically adjusts pacing parameters or alerts the clinician, creating a closed-loop control system that prevents worsening of the harmful effect while maintaining the beneficial cardiac rhythm control.
Solution Approach 2:
The system performs preliminary assessment of hemodynamic tolerance by monitoring autonomic tone changes before severe dyssynchrony develops. By detecting early signs of intolerance through HRV analysis during pacing, the system enables preventive adjustment of pacing parameters before the harmful effects fully manifest, thereby maintaining reliability while reducing harm.
2Productivity
If ventricular pacing is used to treat heart failure, then cardiac output is improved, but symptoms are nonspecific and overlap with other conditions making recognition difficult
Solution Approach 1:
The system introduces heart rate variability as an intermediary marker that indirectly reflects hemodynamic status. Instead of relying on direct measurement of cardiac output or waiting for specific symptoms, HRV serves as a measurable intermediary that changes in response to pacing-induced hemodynamic changes, making detection easier and more objective while maintaining the beneficial cardiac output improvement.
Solution Approach 2:
The system replaces subjective clinical assessment with objective electronic monitoring of autonomic tone through HRV analysis. This substitution of mechanical/clinical detection methods with electronic sensing and signal processing enables continuous, quantifiable monitoring that overcomes the difficulty of detecting nonspecific symptoms, while preserving the productivity benefits of ventricular pacing.
3Measurement precision
If monitoring of autonomic tone is performed continuously, then hemodynamic intolerance is detected early, but device complexity increases
Solution Approach 1:
The system uses existing electrodes and sensing capabilities already present in the pacemaker for dual purposes: both for delivering pacing stimuli and for monitoring autonomic tone through HRV analysis. This multi-functionality allows continuous monitoring of autonomic tone without adding separate dedicated monitoring hardware, thereby achieving early detection while minimizing the increase in device complexity.
Solution Approach 2:
The system merges the monitoring function with the existing pacing system by combining HRV analysis with the same signal processing infrastructure used for pacing delivery. By merging these functions into a unified system architecture, the patent achieves precise autonomic tone detection while avoiding the complexity that would result from completely separate monitoring and pacing systems.
Data Source
AI summary
In some examples, this disclosure describes techniques for assessing hemodynamic intolerance of ventricular pacing. A method comprises sensing a parameter indicative of autonomic tone during a first period in which a medical device delivers ventricular pacing to a patient, sensing the parameter indicative of autonomic tone during a second period in which the medical device does not deliver ventricular pacing to the patient, and assessing a level of change in autonomic tone in the patient induced by ventricular pacing based on values of the sensed parameter during the first and second periods.