His-Bundle Pacing for Cardiac Dyssynchrony
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Solution Overview
Problem
Conventional cardiac pacing methods, such as long-term right ventricular apex pacing, can lead to uncoordinated contraction sequences and adverse long-term effects due to dyssynchronous ventricular activation, while biventricular pacing may not fully restore synchronized contractions and can be complex to implement.
Innovation Solution
A medical system that dynamically controls His-bundle pacing (HBP) based on patient-specific atrioventricular (AV) conduction status, using an electrostimulation circuit to deliver HBP pulses when AV conduction abnormalities are detected and withholding pulses when AV conduction is normal to promote intrinsic ventricular activation, with ventricular backup pacing if HBP fails to capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If right ventricular apex pacing is used to treat cardiac dyssynchrony, then hemodynamic performance is improved, but ventricular activation becomes dyssynchronous leading to adverse long-term effects
Solution Approach 1:
The patent uses the His bundle as an intermediary structure to deliver pacing impulses. By stimulating the His bundle rather than directly pacing the ventricular apex, the electrical impulse propagates through the natural conduction system (AV node → His bundle → bundle branches → Purkinje fibers), thereby restoring synchronized ventricular activation while improving hemodynamic performance.
Solution Approach 2:
The patent replaces the mechanical/electrical direct stimulation of ventricular myocardium with electrical stimulation of the conduction system. Instead of directly depolarizing ventricular muscle fibers (mechanical effect), the pacing impulse travels through the physiological conduction pathways, restoring natural activation sequences.
2Reliability
If biventricular pacing is used to restore synchronized contraction, then ventricular synchrony is improved, but device complexity and surgical difficulty increase
Solution Approach 1:
The patent extracts the pacing function from the ventricular leads and relocates it to the His bundle. By removing the need for complex biventricular lead systems and using only a single ventricular lead positioned at the His bundle, the device complexity is significantly reduced while maintaining synchronized ventricular contraction.
Solution Approach 2:
The His bundle pacing lead serves multiple functions: it delivers pacing impulses to the His bundle, senses ventricular electrical activity, and eliminates the need for separate LV and RV pacing leads. This multi-functional approach simplifies the overall device architecture compared to traditional biventricular pacing systems.
3Reliability
If continuous His-bundle pacing is delivered to maintain AV conduction, then ventricular activation is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic monitoring of AV conduction status rather than continuous pacing. The device periodically assesses whether AV conduction abnormalities are present and only delivers His-bundle pacing when needed, thereby maintaining effective ventricular activation while significantly reducing overall energy consumption compared to continuous pacing.
Solution Approach 2:
The patent uses feedback from AV conduction monitoring to control pacing delivery. The device continuously or periodically monitors AV conduction parameters and adjusts pacing therapy accordingly - delivering pacing only when conduction abnormalities are detected and withholding pacing when conduction is normal, thus optimizing energy efficiency.
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 cardiac synchrony and hemodynamic performance by leveraging the natural conduction mechanisms of the heart, reducing harmful effects associated with RV apex pacing and avoiding unnecessary pacing therapies, thereby enhancing therapy efficacy and reducing energy consumption.
Implementation Method 1
The artificial cardiac pacing system may provide electrical stimulations to one or more portions of the heart such as to restore normal functioning of the heart
Implementation Method 2
an AV conduction monitor circuit to continuously or periodically assess patient AV conduction status, and detect an indication of presence or absence of AV conduction abnormality
Data Source
AI summary
Systems and methods for dynamically controlling HBP delivery based on patient AV conduction status are disclosed. An exemplary medical system includes an electrostimulation circuit to generate HBP pulses to stimulate a His bundle or a bundle branch of the heart. An AV conduction monitor circuit continuously or periodically assesses AV conduction status, and detects an indication of presence or absence of AV conduction abnormality. If an AV conduction abnormality is indicated, a control circuit may control the electrostimulation circuit to deliver the HBP pulses. Ventricular backup pacing may be delivered if HBP fails to capture and elicit ventricular activation. When the AV conduction become normal, the control circuit may withhold HBP delivery and promote patient intrinsic ventricular activation.