Patent Description:
The present disclosure relates generally to catheters that are used in the human body. In particular, the present disclosure relates to a small form-factor flexible electronic circuit suitable for incorporation into an intravascular catheter, such as within the tip of such a catheter.

Catheters are used for an ever-growing number of procedures. For example, catheters are used for diagnostic, therapeutic, and ablative procedures, to name just a few examples. Typically, the catheter is manipulated through the patient's vasculature and to the intended site, for example, a site within the patient's heart.

It is known to incorporate various electronic components into the tips of intravascular catheters. For instance, piezoelectric ultrasound transducers and supported electronics packages (implemented, for example, as an application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA)) may be mounted within the tip of an intracardiac echocardiography (ICE) catheter, such as disclosed in <CIT> and <CIT>. The relatively small size of such components, however, increases the complexity, and therefore the cost, of manufacture. <CIT> discloses circuits comprising a substrate carrying a conductive track. <CIT> discloses a method for manufacturing an electronic assembly. <CIT> discloses a transfer film for use with a flexible circuit compression connector.

Disclosed herein is a flexible electronic circuit, including: a flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface includes a recess; a localization element disposed within the recess; and a conductive connector pad disposed on the flexible substrate.

The flexible substrate includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness. The recess is positioned within the first portion of the flexible substrate, and the conductive connector pad may be disposed on the second portion of the flexible substrate.

The localization element may include a magnetic localization element and/or an impedance-based localization element.

In embodiments of the disclosure, there are a plurality of recesses and a corresponding plurality of localization elements respectively disposed within the plurality of recesses.

Aspects of the disclosure also include a thermistor mounted to the substrate, for example, within the recess.

Further aspects of the disclosure include an ultrasound transducer assembly mounted to the substrate, for example, on the second surface of the substrate.

Still further aspects of the disclosure include an adhesive overlaying at least a portion of the substrate.

Also disclosed herein is a tip assembly for an intravascular catheter. The tip assembly includes a shell; and a flexible electronic circuit disposed within the shell. In turn, the flexible electronic circuit includes: a flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface includes a recess; a localization element disposed within the recess; and a conductive connector pad disposed on the flexible substrate.

In embodiments of the tip assembly, the flexible electronic circuit includes a plurality of recesses and a corresponding plurality of localization elements respectively disposed within the plurality of recesses. The flexible electronic circuit may also include a thermistor and/or an ultrasound transducer assembly mounted to the flexible substrate. The thermistor may be mounted in a recess.

The instant disclosure also relates to an intravascular catheter, including an elongate catheter body terminating at a distal end; a tip assembly secured to the distal end of the elongate catheter body; and a flexible electronic circuit disposed within the tip assembly. The flexible electronic circuit includes: a flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface includes a recess; a localization element disposed within the recess; and a conductive connector pad disposed on the flexible substrate.

In embodiments of the intravascular catheter, the flexible electronic circuit includes a plurality of recesses and a corresponding plurality of localization elements respectively disposed within the plurality of recesses. The flexible electronic circuit may also include a thermistor and/or an ultrasound transducer assembly mounted to the flexible substrate. The thermistor may be mounted in a recess.

The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments.

Aspects of the instant disclosure relate to flexible electronic circuits suitable for use to connect electronics packages integrated into the distal ends of intravascular catheters (e.g., positioned within the distal tip assemblies of such catheters). Those of ordinary skill in the art will appreciate that the teachings herein can be applied to good advantage in connection with various types of catheters, including, but not limited to, intracardiac echocardiography (ICE) catheters.

For purposes of illustration, <FIG> depicts a perspective view of a representative catheter <NUM>, including a shaft <NUM> having a proximal portion <NUM> and a distal portion <NUM>, which terminates in a tip <NUM>. Insofar as the basic construction of catheter <NUM> will be familiar to those of ordinary skill in the art, the details thereof will be omitted herein, except to the extent relevant to an understanding of the instant disclosure.

<FIG> is a schematic representation of the interior of distal portion <NUM> of catheter <NUM>, including tip <NUM>. Tip <NUM> can include a shell <NUM> and a flexible electronic circuit <NUM> disposed within shell <NUM>.

Flexible electronic circuit <NUM>, in turn, includes a flexible substrate <NUM> and a transducer package (e.g., electronics package <NUM> and ultrasound transducer assembly <NUM>) mounted to substrate <NUM>. A wiring harness <NUM>, including a plurality of wires, interconnects flexible electronic circuit <NUM> to an external device, such as an electroanatomical mapping system (e.g., the EnSite Precision™ Cardiac Mapping System of Abbott Laboratories) or a catheter interface module. Only three wires are shown within wiring harness <NUM>, but it should be understood that this is merely exemplary and that more or fewer wires may be used in a device according to the present teachings.

Various details of flexible electronic circuit <NUM> are shown in <FIG> and <FIG>. In embodiments according to the invention, substrate <NUM> includes a first surface (visible in the plane of <FIG>) and a second surface opposite the first surface. The thickness of substrate <NUM> at any given point is defined between the first and second surfaces at that point.

More particularly, and as best illustrated in <FIG>, the thickness of substrate <NUM> can vary along its length. In embodiments according to the invention, substrate <NUM> includes a thicker first portion <NUM> (e.g., to support localization elements) and a thinner second portion <NUM> (e.g., to increase flexibility at the point of interconnection to wiring harness <NUM>). First and second surfaces <NUM>, <NUM>, respectively, define the thickness of the thicker first portion <NUM> of substrate <NUM>, while first and second surfaces <NUM>, <NUM>, respectively, define the thickness of the thinner second portion <NUM> of substrate <NUM>. It is contemplated that the thicker first portion <NUM> of substrate <NUM> may be formed by bonding one or more additional flexible circuit layers to first surface <NUM> to build up the additional thickness.

First surface <NUM> of substrate <NUM> also includes a recess <NUM> (e.g., a trench or groove) into the thickness of substrate <NUM>. According to the invention, recess <NUM> is located within the thicker first portion <NUM> of substrate <NUM>.

Recess <NUM> facilitates reliable and accurate positioning of components on substrate <NUM>. In embodiments of the disclosure, a pair of localization elements <NUM> (e.g., magnetic or impedance-based localization elements) are mounted to substrate <NUM> as part of electronics package <NUM> in a respective pair of recesses <NUM>. For example, a pair of five degree of freedom (5DOF) magnetic localization elements <NUM>, mounted at a slight angle with respect to each other within corresponding recesses <NUM>, as shown in <FIG>, creates a six degree of freedom (6DOF) localization sensor, as described in <CIT>. Solder pads <NUM> provide electrical connection to localization elements <NUM>.

One or more conductive connector pads <NUM> are disposed on substrate <NUM>. Although <FIG> depicts conductive connector pads <NUM> only on first surface <NUM> of substrate <NUM>, this is merely exemplary and the ordinarily-skilled artisan will appreciate that conductive connector pads <NUM> may be placed elsewhere on substrate <NUM> without departing from the scope of the instant disclosure.

Conductive connector pads <NUM> provide points for interconnection with wiring harness <NUM>. Conductive connectors pads <NUM> are also conductively coupled to localization elements <NUM> (e.g., to solder pads <NUM>), so as to carry signals, such as power and communications signals, to and from localization elements <NUM> and, as discussed in further detail below, a temperature sensing element. Insofar as conductive coupling between the attachment point for wiring harness <NUM> and flexible circuit components will be familiar to those of ordinary skill in the art, it need not be further described herein.

In embodiments of the disclosure, flexible electronic circuit <NUM> may include additional components. For example, <FIG> and <FIG> depict a thermistor <NUM> mounted to substrate <NUM>. According to aspects of the disclosure, thermistor <NUM> may be mounted within an additional recess analogous to recesses <NUM>. This not only facilitates reliable and accurate positioning of thermistor <NUM>, but also allows for a quicker thermal response by virtue of its proximity to ultrasound transducer assembly <NUM> through the correspondingly diminished thickness of substrate <NUM>. Other components, such as power supplies, pre-amplifiers, multiplexors, imaging element drivers, additional localization elements, and the like, may also be mounted to substrate <NUM>.

According to aspects of the disclosure, an adhesive may be applied overlaying at least a portion of first and/or second surfaces <NUM>, <NUM> of substrate <NUM>.

<FIG> illustrates flexible electronic circuit <NUM>, with localization elements <NUM> and ultrasound transducer assembly <NUM> mounted thereon for assembly into tip <NUM>.

Although several embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention.

For example, rather than using individual wires, wiring harness <NUM> could utilize one or more long flex and/or printed circuits.

All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

Claim 1:
A flexible electronic circuit (<NUM>) for a catheter, comprising:
a flexible substrate (<NUM>) having a first surface (<NUM>) and a second surface (<NUM>) opposite the first surface (<NUM>), wherein the first surface (<NUM>) includes a recess (<NUM>);
a localization element (<NUM>) disposed within the recess (<NUM>); and
a conductive connector pad (<NUM>) disposed on the flexible substrate (<NUM>) and conductively coupled to the localization element (<NUM>);
wherein the flexible substrate (<NUM>) comprises a first portion (<NUM>) having a first thickness and a second portion (<NUM>) having a second thickness thinner than the first thickness, wherein the recess (<NUM>) is positioned within the first portion of the flexible substrate (<NUM>).