Patent Description:
The present invention is directed toward devices for performing diagnostic and/or therapeutic procedures on tissue and organs. More specifically to devices for perforation procedures such as a transseptal perforation procedure.

In medical procedures involving a patient's heart, there are numerous diagnostic and therapeutic procedures that include transseptal left heart catheterization, i.e. catherization through the left atrium. The transseptal approach provides access for both interventional cardiologists who perform antegrade mitral balloon valvuloplasty and for cardiac electrophysiologists who ablate left sided accessory pathways or perform transcatheter atrialfibrillation therapeutic tactics.

Currently, transseptal puncture can generally involve: (<NUM>) positioning a guide wire in the right atrium; (<NUM>) advancing a transseptal sheath with dilator therein over the guidewire to the right atrium; (<NUM>) delivering a needle through the dilator until a distal end of the needle is inside the dilator a short distance from a distal end of the dilator; (<NUM>) manipulating the sheath and dilator until the dilator distal end is pressed against target tissue; (<NUM>) moving the distal end of the needle out of the dilator and through the tissue to puncture the tissue; and (<NUM>) moving the dilator and sheath through the punctured tissue into the left atrium. In this process, the dilator, transseptal sheath, and/or needle can have some pre-defined curvature at their respective distal ends to aid in positioning of the system for puncture. A procedure using a more simplistic system typically relies on fluoroscopy to visualize the position of the system and mechanical feedback (e.g. feeling a "click" when the dilator tip crosses a tissue ridge) to verify position prior to puncture. In more advanced systems, a sheath having navigation sensors and a distal curvature that can be reshaped during positioning (e.g. CARTO VIZIGO ™ bi-directional guiding sheath) can reduce reliance on fluoroscopy and provide greater mechanical control of the system.

<CIT> discloses a method and device for transseptal facilitation using a location system. During transseptal perforation, once the fossa ovalis is found, a penetrating device such as a HEARTSPAN™ transseptal needle is delivered through vasculature to the fossa ovalis via a sheath such as a PREFACE® Sheath; then the penetrating device exits the sheath and punctures the fossa ovalis. The HEARTSPAN™ transseptal needle and PREFACE® Sheath are available from Biosense Webster, a Johnson and Johnson company.

While in many current treatments, the needle in the above-described procedure is a mechanical needle with a sharp end, structures which rely on electrical energy to puncture are an option. <CIT>, <CIT>, <CIT>, and <CIT> filed July <NUM>, each discloses a respective perforation apparatus which relies on electrical energy for puncture (e.g. radio frequency).

In <CIT>, there is described a medical dilator that includes an elongate member having a proximal end portion, an opposed distal end portion, and a lumen extending through the elongate member from the proximal end portion to the distal end portion. At least a first electrode is associated with the dilating tip. An electrical conductor is electrically connected to the first electrode and extends proximally from the first electrode towards the proximal end portion for electrical connection with an electro anatomical mapping system.

In <CIT>, there is described an apparatus comprising an intravascular sheath and dilator that can be placed over a guidewire after percutaneous vascular access. One or more electrodes are positioned axially at or near the distal end of the dilator, facilitating guidance of the sheath to the heart without fluoroscopy (i.e., by using electrical and/or magnetic guidance). The electrodes are in electrical conductance with leads via wires that extending proximally from the electrodes on or through the wall of the dilator or sheath.

In <CIT>, there is described a catheter configured to extend through a transseptal puncture site, a left atrium, and into a left ventricle.

In <CIT>, there is described a surgical instrument that includes an impedance sensing system for monitoring the position of the tip of the surgical instrument relative to the pericardial space.

In <CIT>, there is described the localization of an introducer sheath relative to an intravascular catheter.

The invention is defined by appended independent claim <NUM>.

The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.

As used herein, the terms "component," "module," "system," "server," "processor," "memory," and the like are intended to include one or more computer-related units, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. Computer readable medium can be non-transitory. Non-transitory computer-readable media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible, physical medium which can be used to store computer readable instructions and/or data.

As used herein, the term "computing system" is intended to include stand-alone machines or devices and/or a combination of machines, components, modules, systems, servers, processors, memory, detectors, user interfaces, computing device interfaces, network interfaces, hardware elements, software elements, firmware elements, and other computer-related units. By way of example, but not limitation, a computing system can include one or more of a general-purpose computer, a special-purpose computer, a processor, a portable electronic device, a portable electronic medical instrument, a stationary or semi-stationary electronic medical instrument, or other electronic data processing apparatus.

As used herein, the term "microcatheter" is a catheter having a diameter that is small in comparison to catheters in cardiovascular applications, i.e. <NUM> French or less.

As used herein, the term "needle" describes a structure having a sharp pointed end designed to puncture tissue.

As used herein, the term "non-transitory computer-readable media" includes, but is not limited to, random access memory (RAM), read-only memory (ROM), electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible, physical medium which can be used to store computer readable information.

As used herein, the term "radiofrequency" (RF) is used to refer to an alternating current that flows through a conductor.

As used herein, the terms "tubular" and "tube" are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, a tubular structure or system is generally illustrated as a substantially right cylindrical structure. However, the tubular system may have a tapered or curved outer surface without departing from the scope of the present disclosure.

In current transseptal puncture procedures, it can be difficult to achieve desired precision in location and angle of puncture. A bulky sheath and dilator can be difficult to precisely position, and a stiff needle can deflect the sheath and dilator as the needle is moved distally through the sheath and dilator and when forced against tissue. In some examples illustrated herein, an example transseptal puncturing system can be used to more safely and/or more precisely perform a transseptal puncture. In some examples the transseptal puncturing system can be less bulky, nimbler, and/or require less puncturing force than many current transseptal puncturing systems.

<FIG> is an illustration of an example transseptal puncturing system <NUM>. The system <NUM> includes a guidewire <NUM>, a microcatheter <NUM>, a generator <NUM>, a return pad <NUM>, a mapping/navigation module <NUM>, and an intralumenal module <NUM>.

The guidewire <NUM> can have a solid conductive core <NUM> and an insulating jacket <NUM>. A distal end <NUM> and a proximal end <NUM> of the guidewire <NUM> can each be non-insulated so that electrical contact can be made from the proximal end <NUM> through the conductive core <NUM> to the distal end <NUM>. Alternatively, the guidewire <NUM> need not include the insulating jacket <NUM>.

The generator <NUM> can be electrically connected to the proximal end <NUM> of the guidewire <NUM> through an easily attachable connector/cable and can provide electrical signals through the core <NUM> of the guidewire <NUM> to the distal end <NUM> of the guidewire that are sufficient to puncture tissue, using RF energy, without requiring a needle or sharp end. The generator <NUM> can provide RF signals to the distal end <NUM> of the guidewire <NUM> that spread from the distal end <NUM> through a body of a patient to the return pad <NUM>. The generator <NUM> can include an impedance monitoring module <NUM> that is configured to measure impedance at the distal end <NUM> of the guidewire <NUM> to help facilitate a use case. The generator <NUM> can be configured to provide electrical energy to the distal end <NUM> of the guidewire <NUM> based at least in part on the impedance measured by the impedance monitoring module <NUM>. Additionally, or alternately, the generator <NUM> can be configured to provide electrical energy to the distal end <NUM> of the guidewire <NUM> based on a fixed predetermined time.

The microcatheter <NUM> has a lumen <NUM> in which the guidewire <NUM> is positioned. The microcatheter <NUM> is aligned along a longitudinal axis L-L. The microcatheter <NUM> can have a deflectable distal portion near a distal end <NUM> of the microcatheter <NUM>. The microcatheter <NUM> can have one or more location sensors <NUM> positioned on the distal portion. The location sensor(s) <NUM> can include one or more magnetic coils and/or one or more impedance sensors.

The mapping/navigation module <NUM> can be in electrical contact with the location sensor(s) <NUM>, for example via one or more electrical conductors extending longitudinally through the microcatheter <NUM> from the location sensors <NUM> to a proximal end <NUM> of the microcatheter <NUM>. The navigation module <NUM> can be configured to determine a position and/or orientation of the distal portion of the microcatheter <NUM> based at least in part on electrical signals from the location sensor(s) <NUM> of the microcatheter <NUM>. The navigation module <NUM> can include an electric tracking sub-system and/or a magnetic position tracking sub-system which can function alone or in a hybrid mode as described in <CIT> or as otherwise understood by a person skilled in the pertinent art. The navigation module <NUM> can further be in electrical contact with the proximal end <NUM> of the guidewire <NUM> and can utilize the distal end <NUM> of the guidewire as a reference electrode for the location sensor(s) <NUM>.

Additionally, or alternatively, the guidewire <NUM> can include one or more location sensors configured as described in relation to location sensor <NUM>.

The intralumenal module <NUM> can be in communication with the lumen <NUM> of the microcatheter <NUM>. The intralumenal module <NUM> can be configured to perform intralumenal steps as understood by a person skilled in the pertinent art such as sensing pressure and/or providing fluids via the lumen <NUM> of the microcatheter <NUM>.

<FIG> is an illustration of components of the example transseptal puncturing system <NUM> illustrated in <FIG> with an exception that the steerable microcatheter 130a has a tapered distal portion <NUM>. The microcatheter 130a illustrated in <FIG> can be shaped and otherwise configured to function as a dilator.

<FIG> is an illustration of a cross section of the system <NUM> as indicated in <FIG>.

Referring collectively to <FIG>, the microcatheter 130a can have a distal outer diameter (DODC) that is greater than, and approximately equal to, an outer diameter of the guidewire (ODG). The microcatheter 130a can have a proximal outer diameter (PODC) that is less than and approximately equal to an inner diameter of the sheath (IDS). The microcatheter <NUM> illustrated in <FIG> can be configured similarly to the microcatheter 130a illustrated in <FIG> with an exception that the proximal outer diameter (PODC) is smaller as the microcatheter <NUM> need not function as a dilator in some applications. The microcatheter <NUM>, 130a can include a pull wire <NUM> that can be pulled to deflect a distal portion of the microcatheter <NUM>, 130a from the longitudinal axis L-L. The pull wire <NUM> can be anchored to the body of the microcatheter 130a by a pull wire anchor <NUM>. The microcatheter <NUM>, 130a can include one or more sensor wires <NUM> electrically connected to the location sensor <NUM>. The microcatheter <NUM>, 130a can include a braid layer <NUM>. The microcatheter <NUM>, 130a can include one or more fluidic/irrigation ports <NUM>. The tapered distal end <NUM> of the microcatheter 130a can be fused to a shaft of the microcatheter 130a.

The guidewire <NUM> can include an insulative jacket <NUM> over a majority of the conductive core <NUM> of the guidewire <NUM>. The insulative jacket <NUM> can define the outer diameter (ODG) of the guidewire <NUM>. When the guidewire <NUM> lacks an insulative jacket <NUM>, the conductive core <NUM> can define the outer diameter (ODG) of the guidewire <NUM>. The microcatheter <NUM>, 130a can have inner diameter (IDC) within the lumen <NUM> of the microcatheter <NUM>, 130a that is greater than and approximately equal to the outer diameter (ODG) of the guidewire <NUM>. The lumen <NUM> of the microcatheter <NUM>, 130a can be tapered such that the inner diameter (IDC) of the microcatheter <NUM>, 130a is smaller at a distal end of the microcatheter <NUM>, 130a. Dimensions of the outer diameter (ODG) of the guidewire <NUM> and inner diameter (IDC) of the microcatheter <NUM>, 130a can be sized such that the guidewire <NUM> is snugly held in the lumen <NUM> of the microcatheter <NUM>, 130a so that the manipulation of the microcatheter <NUM>, 130a precisely controls positioning of the distal end <NUM> of the guidewire <NUM>. Preferably, the dimensions of the outer diameter (ODG) of the guidewire <NUM> and inner diameter (IDC) of the microcatheter <NUM>, 130a as sized to allow longitudinal translation of the guidewire <NUM> within the lumen <NUM> of the microcatheter <NUM>, 130a. The microcatheter <NUM>, 130a can have an outer diameter (ODG) of about <NUM> French or less. The guidewire <NUM> preferably has an outer diameter (ODG) of about <NUM> inches (<NUM> millimeters) to about <NUM> inches (<NUM> millimeters). The microcatheter <NUM>, 130a preferably has an inner diameter (IDC) of about <NUM> inches (<NUM> millimeters) to about <NUM> inches (<NUM> millimeter).

<FIG> are a sequence of illustrations illustrating an example method for transseptal puncture. <FIG> are illustrated with the low profile steerable microcatheter <NUM> illustrated in <FIG>. <FIG> can also be carried out in a similar manner with the steerable microcatheter 130a having a tapered distal portion <NUM> as illustrated in <FIG>.

<FIG> illustrates the microcatheter <NUM> and guidewire <NUM> traversed through the inferior vena cava <NUM> such that a distal portion of the microcatheter <NUM> and the guidewire <NUM> is positioned within the right atrium <NUM>. The distal end <NUM> of the guidewire <NUM> is exposed to blood.

<FIG> illustrates the distal portion of the microcatheter <NUM> being deflected. In some procedures, the microcatheter <NUM> can be deflected and moved about the right atrium <NUM> to map the right atrium. The navigation/mapping module <NUM> can receive electrical signals from the location sensor(s) <NUM> of the microcatheter to map portions of the right atrium <NUM>. For instance, the microcatheter <NUM> can be manipulated to map a portion of a septal wall <NUM> in the right atrium <NUM> to locate a fossa ovalis <NUM> and the ideal placement for the puncture site particular to the procedure being performed. In some examples, the navigation/mapping module <NUM> can receive electrical signals from the electrically conductive distal end <NUM> of the guidewire <NUM> and electrical signals from the location sensor(s) <NUM> such that the distal end <NUM> of the guidewire <NUM> is used as a reference electrode to the location sensor(s) <NUM>.

<FIG> illustrates the microcatheter <NUM> being manipulated to position the electrically conductive distal end <NUM> of the guidewire <NUM> against target tissue, i.e. the septal wall <NUM> at the fossa ovalis <NUM>.

<FIG> illustrates a zoomed in view of the electrically conductive distal end <NUM> of the guidewire <NUM> approaching the fossa ovalis <NUM>. As oriented in the illustration, the fossa ovalis <NUM> aligns with a parallel axis P-P and is orthogonal to a traverse axis T-P. The distal portion of the microcatheter <NUM> can repositioned and deflected to a desired position on the fossa ovalis <NUM> and a desired angle of approach relative to the parallel axis P-P and traverse axis T-P.

As the electrically conductive distal end <NUM> of the guidewire <NUM> approaches tissue of the fossa ovalis <NUM>, impedance at the distal end <NUM> can be monitored by the impedance monitoring module <NUM>. When the distal end <NUM> of the guidewire is far enough from tissue so that it is known through mapping, fluoroscopy, or other means to be in contact with blood, a pre-contact impedance can be sensed by the impedance monitoring module <NUM>. When the distal end <NUM> of the guidewire <NUM> comes into contact with tissue, a tissue impedance can be sensed by the impedance monitoring module <NUM>. Contact of the distal end <NUM> of the guidewire <NUM> to the tissue can be detected by the impedance monitoring module <NUM> as a change in impedance from the pre-contact impedance to the tissue impedance as well as the impedance post penetration of the fossa ovalis tissue <NUM>.

<FIG> illustrates the distal end <NUM> of the guidewire <NUM> positioned within tissue. Electrical energy can be applied by the generator <NUM> to the electrically conductive distal end <NUM> of the guidewire <NUM> to ablate or otherwise create damaged tissue <NUM> around the distal end <NUM> of the guidewire <NUM>.

Mechanically, the distal end <NUM> of the guidewire can be atraumatic, i.e. lacking a traumatic or sharp end such that absent application of the electrical energy from the generator <NUM>, the guidewire <NUM> is unable to puncture tissue. The system <NUM> need not require a needle to puncture tissue. The distal end <NUM> of the guidewire <NUM> can have a hemispherical shape as illustrated, a flat shape, a domed shape, or other such atraumatic shape. In contrast, <CIT> discloses a guidewire with a piercing end configured to mechanically pierce tissue absent application of electrical energy. The guidewire <NUM> of the present disclosure need not have such piercing end to puncture tissue because tissue puncture can be achieved by application of electrical energy to the distal end <NUM> of the guidewire <NUM>.

<FIG> illustrates the distal end <NUM> of the guidewire <NUM> exiting the tissue into the left atrium <NUM>. In some examples, tissue impedance can be monitored by the impedance monitoring module <NUM> while the distal end <NUM> of the guidewire <NUM> travels through the tissue. A change in impedance from the tissue impedance to the post-contact impedance sensed by the impedance monitoring module <NUM> can indicate that the distal end <NUM> has entered the left atrium <NUM>. The generator <NUM> can cease application of electrical energy in response to the change in impedance detected by the impedance monitoring module <NUM> when the distal end <NUM> enters the left atrium <NUM>.

Additionally, or alternatively the generator <NUM> can cease application of electrical energy in response to time elapsed from a start time. The time at which the distal end <NUM> of the guidewire initially contacts the tissue of the fossa ovalis <NUM> can be sensed by the impedance monitoring module <NUM> and recorded or otherwise utilized as the start time used as a reference for when to terminate application of electrical energy from the generator <NUM>. Alternatively, the start time can be determined based on initial application of electrical energy from the generator <NUM> to the distal end <NUM> of the guidewire <NUM>. Supply of electrical energy from the generator <NUM> can be terminated when a predetermined time has elapsed following the start time. In some examples, the predetermined time can be set to as high as about <NUM> seconds; however, during most treatments, crossing can be completed within <NUM> millisecond, and therefore the predetermined time can be set at about <NUM> milliseconds to about <NUM> milliseconds.

<FIG> illustrates the guidewire <NUM> being further moved distally into the left atrium <NUM>. At the illustrated instance, the electrical energy from the generator <NUM> is preferably ceased due to change in impedance and/or elapse of time as disclosed above; however, in a treatment in which the electrical energy remains applied from the generator <NUM>, the insulative jacket <NUM> over the guidewire <NUM> can inhibit further damage to tissue of the fossa ovalis <NUM>. Alternatively, the energy from the generator <NUM> can be precisely controlled to shut off before tissue is overly damaged, in which case the insulative jacket <NUM> is not necessary to inhibit further damage to tissue.

<FIG> illustrates an optional step in which the microcatheter <NUM> crosses the fossa ovalis <NUM>. While positioned as illustrated, the intralumenal module <NUM> can perform intralumenal steps as understood by a person skilled in the pertinent art such as sensing pressure and/or providing fluids via the lumen <NUM> of the microcatheter <NUM>.

<FIG> illustrates a dilator <NUM> and sheath <NUM> moved distally over the guidewire <NUM> to the transseptal puncture through the fossa ovalis <NUM>. The microcatheter <NUM> can be removed prior to this step (as illustrated), or alternatively, the microcatheter <NUM> can be left in place so that the dilator <NUM> and sheath <NUM> are moved distally over the microcatheter <NUM>. The dilator <NUM> and sheath can be moved through the transseptal puncture, and treatment within the left atrium <NUM> can proceed according to various methods as understood by a person skilled in the pertinent art.

<FIG> are a sequence of illustrations which can be performed in place of the steps illustrated in <FIG> and <FIG> when the steerable microcatheter 130a is tapered to function as a dilator as illustrated in <FIG>.

<FIG> illustrates the tapered dilator positioned entirely in the right atrium <NUM> such that the distal end <NUM> is positioned at the fossa ovalis immediately following the step described in relation to <FIG>.

<FIG> illustrates the sheath <NUM> being moved over the microcatheter 130a.

<FIG> illustrates the microcatheter 130a dilating the opening in the fossa ovalis <NUM> as the distal end <NUM> of the microcatheter 130a enters the left atrium <NUM>. While positioned as illustrated, the intralumenal module <NUM> can perform intralumenal steps as understood by a person skilled in the pertinent art such as sensing pressure and/or providing fluids via the lumen <NUM> of the microcatheter <NUM>.

<FIG> is a flow diagram outlining steps of an example method <NUM> for transseptal puncture. At step <NUM>, a steerable microcatheter and guidewire can be positioned in a right atrium such that an electrically conductive distal end of the guidewire is positioned near a distal end of the steerable microcatheter and exposed to blood. The microcatheter and guidewire can be configured similarly to the microcatheter <NUM> and the guidewire <NUM> disclosed herein, variations thereof, and alternatives thereto as understood by a person skilled in the pertinent art.

At step <NUM>, at least a portion of an interatrial septum can be mapped using a location sensor of the microcatheter. The location sensor can be configured similarly to the location sensor(s) <NUM> disclosed herein, variations thereof, and alternatives thereto as understood by a person skilled in the pertinent art.

At step <NUM>, a position of the distal end of the microcatheter can be determined using the location sensor.

At step <NUM>, the distal end of the microcatheter can be steered to thereby steer the distal end of the guidewire to target tissue.

At step <NUM>, contact of the distal end of the guidewire to tissue can be detected based at least in part on an impedance measurement at the distal end of the guidewire.

At step <NUM>, while the distal end of the guidewire is in contact with tissue, electrical energy can be applied to the distal end of the guidewire to cause tissue puncture.

At step <NUM>, the guidewire can be advanced through the target tissue. The microcatheter can also be advanced through the target tissue, preferably after the electrical energy to the guidewire is terminated
At step <NUM>, the electrical energy at the distal end of the guidewire can be terminated based at least in part on an impedance measurement at the distal end of the guidewire.

At step <NUM>, the guidewire can be retained across the target tissue such that the distal end of the guidewire is in the left atrium. The microcatheter may also be retained across the target tissue.

At step <NUM>, a dilator and a sheath can be advanced over the guidewire, across the target tissue, and into the left atrium. If the microcatheter is retained across the target tissue, the dilator and sheath can be advanced over the microcatheter, across the target tissue, and into the left atrium.

<FIG> is an illustration of a transseptal perforation procedure using a computer-aided system <NUM>. The system <NUM> can be used during a medical procedure on a heart <NUM> of a patient <NUM> to perform transseptal perforation. The procedure can be performed by one or more operators including a medical professional <NUM>. The system <NUM> can be configured to present images of a cavity, such as an internal chamber of heart <NUM>, allowing operator <NUM> to visualize characteristics of the cavity. The system <NUM> can further be configured to present images of the microcatheter <NUM> and/or guidewire <NUM>. The system <NUM> can further include and/or be configured to control components of the transseptal perforation system <NUM> illustrated in <FIG>.

The system <NUM> can be controlled by a system processor <NUM> which can be realized as a general-purpose computer. The processor <NUM> can be mounted in a console <NUM>. The console <NUM> can include operating controls <NUM> such as a keypad and a pointing device such as a mouse or trackball that the operator <NUM> can use to interact with the processor <NUM>. Results of the operations performed by the processor <NUM> can be provided to the operator on a display <NUM> connected to the processor <NUM>. The display <NUM> can further present a graphic user interface to the operator enabling the operator to control the system <NUM>. The operator <NUM> may use controls <NUM> to input values of parameters used by the processor <NUM> in the operation of the system <NUM>.

The processor <NUM> uses computer software to operate the system <NUM>. The software can be downloaded to the processor <NUM> in electronic form, over a network, for example, or it can, alternatively or additionally, be provided and/or stored on non-transitory tangible computer-readable media, such as magnetic, optical, or electronic memory.

The operator <NUM> can insert the microcatheter <NUM> and guidewire <NUM> into the patient <NUM>, so that a distal end of the microcatheter <NUM> and guidewire <NUM> enters right atrium <NUM> of the patient's heart via the inferior vena cava <NUM>. The processor <NUM> can be configured to track the distal end <NUM> of the microcatheter and the distal end <NUM> of the guidewire <NUM>, typically both the location and the orientation of the distal ends <NUM>, <NUM>, while they are within heart <NUM>. When the sensor(s) <NUM> of the microcatheter <NUM> include one or more magnetic coil(s), the processor <NUM> can utilize a magnetic tracking system such as is provided by the Carto® system produced by Biosense Webster. The system <NUM> can include magnetic field transmitters <NUM> in the vicinity of patient <NUM>, so that magnetic fields from the transmitters interact with magnetic coil(s) near the distal end <NUM> of the microcatheter <NUM>. The coils interacting with the magnetic fields generate signals which are transmitted to the processor <NUM>, and the processor analyzes the signals to determine the location and orientation of the guidewire <NUM> and microcatheter <NUM>.

Additionally, or alternative, the system <NUM> can include body patches (not illustrated) for an electrical tracking sub-system that is impedance based, also referred to as an advanced current localization (ACL) tracker sub-system. In the ACL sub-system, current is delivered to an impedance sensor that is within the patient's body, the current spreads from the impedance sensor through the body to the body patches, and location of the impedance sensor is calculated based on current distribution at the body patches. The sensor(s) <NUM> of the microcatheter <NUM> can include one or more impedance sensors, and/or the electrically conductive distal end <NUM> of the guidewire <NUM> can function as an impedance sensor.

The system <NUM> can include a magnetic tracking sub-system and/or an ACL sub-system configured similarly to as disclosed in <CIT>.

The console <NUM> can further be configured to monitor impedance and/or control electrical energy to guidewire <NUM> as illustrated and described elsewhere herein.

Claim 1:
A transseptal puncturing system (<NUM>) comprising:
a steerable microcatheter (<NUM>) comprising an elongated member with a lumen (<NUM>) extending therethrough to define a longitudinal axis, a deflectable distal portion (<NUM>), and a location sensor (<NUM>) disposed proximate the deflectable distal portion;
a guidewire (<NUM>) disposed within the lumen of the microcatheter comprising an electrically conductive core (<NUM>), an electrically conductive distal end (<NUM>), an electrically conductive proximal end (<NUM>), and an outer diameter (ODG) less than and approximately equal to an inner diameter (IDC) of the lumen of the microcatheter;
a generator (<NUM>) in electrical contact with the electrically conductive proximal end, the generator being configured to provide electrical energy to the distal end of the guidewire sufficient to puncture tissue without requiring a sharp end; and
an impedance monitoring module (<NUM>) in communication with the generator, in electrical communication with the proximal end of the guidewire, and configured to measure impedance at the distal end of the guidewire,
wherein the generator is configured to provide the electrical energy to the distal end of the guidewire based at least in part on the measured impedance.