His Bundle Pacing Lead With Fixation Helix
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Solution Overview
Problem
Current cardiac rhythm management systems face challenges in effectively stimulating the His bundle of the heart, often resulting in pacing-induced dyssynchrony, particularly with right ventricular apex pacing, necessitating improved lead designs for precise and reliable stimulation.
Innovation Solution
An implantable medical lead system comprising a pulse generator and a multi-polar medical electrical lead with a fixation helix and dual coil conductors, designed for subcutaneous implantation, which delivers electrical pacing stimuli directly to the His bundle, featuring a tapered distal tip assembly with a fixation helix and a stylet for precise torque transfer and fixation, along with a separable guide catheter for targeted delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If right ventricular apex pacing is used, then cardiac rhythm management is achieved, but pacing-induced dyssynchrony occurs
Solution Approach 1:
The patent uses the His bundle as an intermediary structure to achieve ventricular pacing. Instead of directly pacing the ventricular apex, the lead delivers electrical stimulation through the His bundle (an intermediate conduction structure) to activate the ventricles, thereby achieving rhythm management while avoiding dyssynchrony. The fixation helix and tapered tip assembly serve as intermediaries to precisely position the electrode at the His bundle location.
Solution Approach 2:
The lead is segmented into distinct functional components: the fixation helix for anchoring, the tapered tip assembly for precise positioning, and the electrode for stimulation. This segmentation allows each component to perform its specific function optimally, with the fixation helix providing stable attachment and the tapered tip enabling accurate His bundle targeting to achieve synchronous ventricular activation.
2Ease of operation
If conventional lead designs are used, then implantation is simplified, but precise His bundle stimulation is difficult to achieve
Solution Approach 1:
The lead incorporates a pre-formed fixation helix and tapered tip assembly that are prepared in advance during manufacturing. The helix is pre-shaped and the tip is pre-tapered to facilitate easy insertion and automatic engagement with the His bundle tissue during implantation, combining implantation simplicity with positioning precision.
Solution Approach 2:
The lead features localized structural modifications at specific regions: the fixation helix provides anchoring function at the distal end, while the tapered tip assembly provides penetration function at the very distal tip. This local differentiation of structural quality allows the lead to perform multiple functions (easy insertion and precise positioning) without compromising overall implantation simplicity.
3Stability of the object's composition
If the fixation helix is extended distally, then anchoring stability is improved, but the electrode spacing is reduced
Solution Approach 1:
The patent resolves the spacing conflict by transitioning from a linear arrangement to a three-dimensional configuration. The fixation helix extends distally along the longitudinal axis to provide anchoring stability, while the electrode is positioned on the tapered tip assembly that protrudes radially or at an angle from the helix axis. This dimensional change allows both the helix to be extended for stability and the electrode to maintain adequate spacing for effective stimulation.
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 enables selective His bundle pacing with low capture thresholds and efficient ventricular capture, reducing pacing-induced dyssynchrony by providing precise and stable electrical stimulation, allowing for both His bundle and ventricular pacing with high reliability.
Implementation Method 1
The stylet is configured to transmit a torque applied at its proximal end to the distal tip assembly to cause rotation of the fixation helix and the lead body
Implementation Method 2
The implantable pulse generator is configured for subcutaneous implantation in the patient and to generate an electrical pacing stimulus
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A system for therapeutically stimulating a His bundle includes an implantable pulse generator and a multi-polar medical electrical lead. The generator is configured for subcutaneous implantation and to generate a pacing stimulus. The lead includes a connector assembly, a flexible tubular body, a distal tip assembly and coil conductors. The body extends intravascularly from the generator to a location proximate the His bundle and includes a proximal end, a distal end, and a longitudinal lumen. The tip assembly includes an electrode, a fixation helix, and a shank portion. The helix extends to a location proximate the His bundle and is operable as an electrically isolated electrode. The shank portion extends within the lumen and includes a receptacle for receiving a stylet tip. The conductors extend longitudinally through the lumen and are coupled to the electrode and the helix. One or both of the conductors defines a stylet lumen.