His-Bundle Pacing Capture Verification via Far-Field Ventricular Activation
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Solution Overview
Problem
Conventional cardiac pacing methods, such as long-term RV apex pacing, can lead to uncoordinated contraction sequences and adverse hemodynamic effects, while biventricular pacing may not fully restore synchronized contractions, and existing capture verification techniques face challenges in accurately determining His-bundle capture status due to small evoked depolarization amplitudes and proximity to atrial myocardium.
Innovation Solution
A system that includes an electrostimulator to generate pulses for the His bundle or bundle branch, a sensing circuit to detect far-field ventricular activation, and a control circuit to determine cardiac synchrony indicators and verify capture status using QRS width or morphology, allowing for individualized pacing threshold adjustment and improved therapy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RV apex pacing is used to provide electrical stimulation to the heart, then cardiac pacing function is achieved, but uncoordinated contraction sequences and adverse hemodynamic effects occur
Solution Approach 1:
The patent uses the His bundle as an intermediary structure to deliver electrical stimulation to the ventricles through the natural conduction system (AV node → His bundle → bundle branches → Purkinje fibers), rather than directly stimulating ventricular myocardium. This intermediary approach preserves the normal sequential activation pattern of the ventricles, eliminating uncoordinated contraction sequences while maintaining reliable pacing function.
Solution Approach 2:
The patent replaces the mechanical/electrical direct stimulation of ventricular myocardium (RV apex pacing) with electrical stimulation of the conduction system (His bundle pacing). By substituting the stimulation target from ventricular muscle to conduction tissue, the natural electrical propagation mechanics are preserved, resulting in coordinated ventricular contraction while maintaining pacing reliability.
2Reliability
If biventricular pacing is used to restore synchronized contraction, then some synchrony is achieved, but coordinated cardiac contractions similar to natural depolarization are not fully restored
Solution Approach 1:
By stimulating the His bundle as an intermediary point in the conduction system, the patent restores the natural electrical propagation pathway through bundle branches and Purkinje fibers to both ventricles. This intermediary stimulation approach reproduces the physiological sequence of ventricular activation more accurately than biventricular pacing, achieving both synchrony and coordination.
Solution Approach 2:
The patent changes the stimulation parameter from direct ventricular myocardial stimulation (biventricular pacing) to conduction system stimulation (His bundle pacing). This parameter change in the stimulation target allows restoration of the natural electrophysiological parameters of ventricular activation, including proper sequence and coordination, while maintaining synchronized contraction.
3Extent of automation
If conventional capture verification techniques are used to determine His-bundle capture status, then verification is attempted, but accurate determination is difficult due to small evoked depolarization amplitudes and proximity to atrial myocardium
Solution Approach 1:
The patent extracts the verification of capture status from direct electrical signal analysis (which is confounded by small amplitudes and atrial interference) and replaces it with observation of the mechanical/physiological effect (ventricular activation pattern). By taking out the verification from the electrical domain to the physiological outcome domain, measurement precision is dramatically improved.
Solution Approach 2:
The patent substitutes electrical signal analysis (prone to interference) with physiological response measurement (ventricular activation pattern). By replacing the electrical measurement system with a physiological outcome assessment, the system overcomes the limitations of small signal amplitudes and atrial myocardium interference, achieving accurate capture status determination.
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
The system effectively verifies His-bundle capture status and adjusts pacing thresholds, enhancing cardiac synchrony and reducing long-term harmful effects of RV apex pacing, thereby improving cardiac performance and reducing unnecessary medical interventions.
Implementation Method 1
An electrostimulator is configured to generate electrostimulation pulses to stimulate a His bundle or a bundle branch
Implementation Method 2
sense a far-field ventricular activation
Data Source
AI summary
Systems and methods for pacing cardiac conductive tissue are described. In an embodiment, a medical system includes an electrostimulation circuit to generate pacing pulses to stimulate a His bundle or a bunch branch. A sensing circuit senses a far-field ventricular activation, determines a cardiac synchrony indicator using the far-field ventricular activation in response to His bundle or bundle branch pacing, and verifies His-bundle capture status using the determined cardiac synchrony indicator. The system can determine a pacing threshold using the capture status under different stimulation strength values. The electrostimulation circuit can deliver stimulation pulses in accordance with the determined pacing threshold.