Summation Anodal Pacing for His Bundle Capture
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Solution Overview
Problem
Traditional cardiac pacing methods rely solely on cathodal capture, which can be inefficient in diseased tissue or areas with poor electrode contact, and have theoretical concerns about anodal capture being pro-arrhythmic and mechanically detrimental, despite recent evidence suggesting anodal capture may have salutary effects.
Innovation Solution
The development of a pacing device and method that enables anodal capture using a bipolar or multipolar lead, where the anode serves as a common electrode for multiple cathodes, creating a larger virtual electrode and reducing anodal pacing thresholds, allowing for more effective stimulation of the myocardium, including the His bundle and bi-atrial pacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cathodal capture pacing is used, then myocardial stimulation is achieved, but pacing efficiency is reduced in diseased tissue or areas with poor electrode contact
Solution Approach 1:
The patent inverts the traditional cathodal capture approach by utilizing anodal capture instead. By applying current through the anode to create a virtual cathode in the myocardium, the system achieves effective stimulation even in diseased tissue or areas with poor electrode contact, thereby resolving the reliability issue with traditional cathodal pacing.
Solution Approach 2:
The patent introduces the concept of a 'virtual cathode' as an intermediary mechanism. The anodal current creates a virtual cathode region in the myocardium where depolarization occurs, serving as a mediator that enables effective pacing without requiring direct cathodal electrode contact with the tissue.
2Reliability
If anodal capture is used to stimulate myocardium, then pacing efficiency improves in diseased tissue, but theoretical concerns arise about pro-arrhythmic effects and mechanical deterioration
Solution Approach 1:
The patent changes the electrical parameters by utilizing anodal current with specific pulse widths and amplitudes to create virtual cathodes. By controlling these parameters, the system achieves effective myocardial stimulation while avoiding the theoretical harmful effects associated with traditional anodal capture, thus resolving the contradiction between improved efficacy and potential harm.
3Area of stationary object
If a single anode serves multiple cathodes, then the area of myocardium that can be stimulated increases, but current density at the anode decreases
Solution Approach 1:
The patent segments the stimulation function by creating multiple virtual cathodes in the myocardium, each serving a specific region. This segmentation allows a single anode to effectively stimulate multiple distinct areas of the myocardium without requiring excessive current density at the anode itself, as the current is distributed to create multiple focal points of depolarization.
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 reduces anodal pacing thresholds, increases the area of myocardium that can be stimulated, and allows for efficient capture of discrete structures like the His bundle without excessive battery energy expenditure, improving heart rhythm synchronization and reducing instances of heart failure.
Implementation Method 1
When the anodal surface area is sufficiently small, this creates an area of hyper-polarization of the myocardial cell membrane
Implementation Method 2
In turn, this sets up a 'virtual cathode' remote from the anode. The virtual cathode results in depolarization of the heart in a manner similar to the virtual cathode at the true fixed cathode
Implementation Method 3
Conventional pacing uses cathodal capture to excite heart muscle. By delivering a current impulse (electrons) via a conductor, a segment of the myocardial cell membrane is rendered more negative such that the threshold potential is reached
Implementation Method 4
By delivering a current impulse (electrons) via a conductor
Data Source
AI summary
A device and method for cardiac pacing is disclosed in which anodal pacing of the left ventricle is provided. Anodal pacing occurs when an anodal surface area is sufficiently small to create an area of hyper-polarization of the myocardial cell membrane. This creates a virtual cathode at a location remote from the anode. The virtual cathode results in depolarization of the heart in a manner similar to the virtual cathode at the true fixed cathode. In addition a device and method for summation anodal pacing is provided in which one anode is common between two or more cathodes. This results in hyperpolarization of a larger segment of the myocardium as compared to non-summation anodal pacing and thereby forms a larger virtual electrode to enable capture of localized, discrete cardiac structures such as the bundle of His or the very proximal portions of the right and left bundles.