FIELD OF THE PRESENT DISCLOSURE

This disclosure relates generally to methods and devices for percutaneous medical treatment, and specifically to catheters that have temperature sensing capabilities, such as ablation catheters. More particularly, this disclosure relates to a cartridge for use during manufacture of an electrode to reliably position a plurality of thermocouples or other components.

BACKGROUND

Radiofrequency (RF) electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity. Specifically, targeted ablation may be performed for a number of indications. For example, ablation of myocardial tissue is well known as a treatment for cardiac arrhythmias by using a catheter to apply RF energy and create a lesion to break arrhythmogenic current paths in the cardiac tissue. As another example, a renal ablation procedure may involve the insertion of a catheter having an electrode at its distal end into a renal artery in order to complete a circumferential lesion in the artery in order to denervate the artery for the treatment of hypertension.

In such procedures, a reference electrode is typically provided and may be attached to the skin of the patient or by means of a second catheter. RF current is applied to the tip electrode of the ablating catheter, and current flows through the media that surrounds it, i.e., blood and tissue, toward the reference electrode. The distribution of current depends on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than the tissue. Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause cellular destruction in the target tissue resulting in formation of a lesion which is electrically non-conductive. The lesion may be formed in tissue contacting the electrode or in adjacent tissue. During this process, heating of the electrode also occurs as a result of conduction from the heated tissue to the electrode itself. As will be appreciated, it is desirable to employ catheters that can sense temperature to help guide the procedure, such as by offering an indication when an efficient ablation temperature has been reached or by reducing conditions under which tissue may be overheated. It is further desirable to provide such electrodes with the ability to sense temperature at multiple locations to more accurately monitor and control the procedure. Accordingly, the temperature sensing elements should be placed accurately and reproducibly within the electrode to maintain consistency among each manufactured electrode.

When the electrode reaches critical temperatures, denaturation of blood proteins causes coagulum formation. Impedance can then rise and limit current delivery. Within tissue, overheating can cause steam bubble formation (steam “pops”) with risk of uncontrolled tissue destruction or undesirable perforation of bodily structures. To help mitigate overheating, ablation catheters may be irrigated. For example, Biosense Webster Inc. (Diamond Bar, Calif.) offers the ThermoCool® irrigated-tip catheter for use with its CARTO® integrated mapping and ablation system. The metal catheter tip, which is energized with radio-frequency (RF) electrical current to ablate the tissue, has a number of peripheral holes, distributed circumferentially around the tip, for irrigation of the treatment site. A pump coupled to the catheter delivers saline solution to the catheter tip, and the solution flows out through the holes during the procedure in order to cool the catheter tip and the tissue. Representative details concerning irrigated ablation catheters may be found in commonly-owned U.S. Pat. No. 9,675,411, whose disclosure is incorporated herein by reference in its entirety. Although ablation catheters may be irrigated to provide greater control over the temperature of catheter components and the surrounding tissue, it is still important to accurately monitor temperature at multiple locations. Indeed, the flow of irrigation fluid may be tailored in part based on feedback from the temperature sensors.

While ablation catheters have been discussed as being a representative example, one of ordinary skill in the art will recognize that many types of intravascular devices may benefit from improved temperature sensing capabilities, particularly with regard to techniques help ensure consistent and reproducible placement during manufacture. Accordingly, it would be desirable to provide a cartridge to position multiple temperature sensing elements within an electrode accurately and reliably. As will be described in the following materials, this disclosure satisfies these and other needs.

SUMMARY

The present disclosure is directed to a positioning cartridge for use during manufacture of an electrode. The positioning cartridge may have a plurality of positioning inserts, each with proximal and distal ends, and a scaffold secured to the proximal ends of each positioning insert. The scaffold may be configured to place the positioning inserts in a defined orientation with respect to each other that corresponds to a plurality of longitudinal bores of the electrode.

In one aspect, the scaffold may have at least one arm.

In one aspect, the positioning cartridge may have two positioning inserts and the at least one arm may be secured to each positioning insert.

In one aspect, the scaffold may have at least one arm and each arm may be secured to at least one of the positioning inserts. Further, each arm may be secured to at least two of the positioning inserts.

In one aspect, each positioning insert may have a longitudinal slot. Each longitudinal slot may have a distal stop. Each longitudinal slot may be located at an outermost radius of the positioning cartridge.

In one aspect, the positioning cartridge may include at least one component disposed within each longitudinal slot. The at least one component may be at least one temperature sensor. Additionally, at least two temperature sensors may be disposed within each longitudinal slot.

In one aspect, the positioning cartridge may be deployed within the electrode. Each positioning insert may have at least one associated temperature sensor.

In one aspect, the positioning cartridge may be molded as a monolithic element.

In one aspect, the scaffold further may have a frangible junction adjacent each of the positioning inserts.

This disclosure is also directed to a method for manufacturing an electrode. The method may include providing the electrode, such that the electrode has a plurality of longitudinal bores, providing a positioning cartridge having a plurality of positioning inserts secured by a scaffold configured to place each positioning insert in a defined orientation with respect to each other that corresponds to the longitudinal bores of the electrode, deploying the positioning cartridge within the electrode so that each positioning insert is disposed within each longitudinal bore and removing the scaffold while leaving each positioning insert is disposed within each longitudinal bore.

In one aspect, the positioning cartridge may have a plurality of components, such that at least one component is associated with each positioning insert. The plurality of components may be temperature sensors. The positioning cartridge may be configured to position each temperature sensor at a location adjacent an outer surface of the electrode.

