Abstract:
A device for creating a surgical perforation with a functional distal tip for creating a controlled perforation. The functional tip may comprise at least one active electrode for creating the perforation through the application of Radio Frequency (RF) energy. The device is curved in order to decrease the likelihood of injury to structures of a patient such as inadvertent cardiac perforation when used in transseptal perforation procedures. The device is introduced into the right atrium, and the functional tip is then positioned against the atrial septum. Energy is applied to create the perforation. The tip is advanced toward the left atrium to create the perforation and as it advances into the left atrium, the device takes on its curved shape to direct the tip away from cardiac structures. The position of the tip of the device can be determined in response to pressure sensed at the tip and determined by a monitor.

Description:
TECHNICAL FIELD 
   The invention relates to a device for creating a perforation in material of a patient such as the septum of the heart. More specifically, the invention relates to a device for creating a perforation in the material while minimizing the risk of inadvertent injury to other patient structures. 
   BACKGROUND OF THE ART 
   It is often required to create a perforation in the atrial septum to gain access to the left side of the heart interventionally to study or treat electrical or morphological abnormalities. It is also often desirable to create a hole in the atrial septum in patients with congenital heart defects in order to shunt the blood flow between the left and right sides of the heart to relieve high pressure or provide more blood flow to certain areas. Historically in these instances, a needle such as the Transseptal needle set of Cook Incorporated, Bloomington, Ind., USA is used. The needle is made of a stiff metal cannula, and has a sharpened distal tip. The needle is introduced through a guiding sheath in the femoral vein and advanced through the vasculature into the right atrium. From there the needle tip is positioned at the fossa ovalis, the preferred location on the septum for creating a perforation. Once in position, the operator applies force at the proximal end of the needle and uses mechanical energy to advance the needle through the septum and into the left atrium. Once in the left atrium the needle can be attached to an external pressure transducer and the operator can confirm a left atrial pressure before continuing with the procedure. Examples of subsequent steps may include advancing the guiding sheath over the needle and into the left atrium to provide access for other devices to the left heart, or using another device to enlarge the hole made by the needle if a shunt is desired. 
   This method of creating a transseptal perforation relies on the skill of the operator and requires practice to be performed successfully (Sethi et al, 2001). The needles used in this procedure are very stiff and can damage the vessel walls as they are being advanced. In addition, the amount of force required to perforate the septum varies with each patient. The force applied by the needle usually causes the septum to tent, or buckle, before it perforates the tissue. Once the needle makes the perforation, the needle may have significant forward momentum, which can be difficult to control. If too much force is applied there is the possibility of the needle perforating the septum and continuing to advance so far that damage is done to other areas of the heart. C. R. Conti (1993) discusses this possibility, and states that if the operator is not careful, the posterior wall of the heart can be punctured by the needle when it crosses the atrial septum because of the proximity of the two structures. Unintentional cardiac perforation has been shown in a number of studies to be a real concern during transseptal procedures, with incidence rates up to 6.7% (Stefanadis et al 1998, Sethi et al 2001). 
   U.S. Pat. No. 6,565,562 “Method for the radio frequency perforation and the enlargement of a body tissue” issued to Shah et al. describes a method of perforating tissue such as an atrial septum using a radiofrequency (RF) perforating device. A functional tip on the RF perforating device is placed against target tissue and as RF current is applied a perforation is created. This method allows a perforation to be created without applying significant force that causes the tissue to tent and the RF perforating device easily passes through the tissue. However, even with this method there is danger of causing unwanted injury to other areas of the heart because the perforating device can be advanced too far unknowingly while RF current is being applied. 
   Patients requiring transseptal punctures would benefit from a device that decreases the risk of unwanted injury, which may include inadvertent puncture, perforation, laceration, or damage to cardiac structures. In particular, patients with a muscular septum, as well as those with a thick septum can benefit from an alternative to the transseptal needle puncture (Benson et al, 2002), as it is difficult to control the amount of mechanical force required to create the puncture. Furthermore, children born with heart defects such as hypoplastic left heart syndrome could benefit from an alternative technique. The abnormal anatomy of these patients including a small left atrium increases the likelihood of injury or laceration of surrounding structures during transseptal puncture (Sarvaas, 2002). 
   A solution to one or more of these shortcomings is therefore desired. 
   SUMMARY OF THE INVENTION 
   The invention provides a surgical device for creating a perforation in material of a patient, including in particular, material that comprises the interatrial septum. The invention seeks to provide a device that is associated with a decreased risk of unintentional injury to other areas of the heart. 
   In accordance with the invention, there is provided a device for creating a perforation in material within a patient. The device comprises an elongate member having a proximal region and a distal region capable of adopting a curved shape; and a functional tip at the distal region for delivering energy to create the perforation in the material. When the functional tip advances through the material, the distal region adopts a curved shape to direct the functional tip in a desired direction. The material may comprise a body tissue, for example the atrial septum of a heart. A feature of the invention is that the curved shape may be defined by a radial arc and a further feature of the proximal region includes a marking indicative of the orientation of the curved shape. 
   In accordance with a further aspect, the invention provides a device for creating a perforation in a heart septum. The device comprises an elongate member having a proximal region and a distal region capable of adopting a curved shape; and a functional tip at the distal region for delivering energy to create the perforation in the septum. When the functional tip advances through the septum, the distal region adopts a curved shape to direct the functional tip in a desired direction. The curved shape may be defined by a radial arc and the functional tip may be directed away from cardiac structures. In particular, the functional tip is directed away from cardiac structures in order to decrease the risk of unwanted injury. 
   Preferably, the proximal region comprises a marking indicative of the orientation of the curved shape. 
   As a feature of this aspect, when the energy form is mechanical, the functional tip comprises a sharp tip. In such a case, the portion of the distal region defining the curved shape may be made of a super-elastic metal. 
   However, the energy may be at least one form of energy selected from a group consisting of: electrical current; microwave; ultrasound; mechanical; and laser. When the energy is electrical current, it may have a frequency within the radio frequency (RF) range. When the electrical current energy is in the RF range, it may be applied to ionize a conductive medium on top of a target tissue resulting in a low temperature molecular disintegration. 
   When the energy form is electrical, the functional tip may comprise at least one active electrode. Further the functional tip may comprise two or more electrodes and the electrodes may be configured in an arrangement where at least one of the electrodes is active and at least one is a return electrode. 
   As a feature of this aspect, the device may comprise a pressure sensing mechanism associated with the distal region for monitoring pressure about the distal region. The pressure sensing mechanism may comprise a pressure transmitting lumen extending between the proximal and distal regions. The lumen is adapted at the proximal region for fluid communication with a pressure transducer and adapted at the distal region for fluid communication with an environment about the distal region. Preferably, the distal region defines at least one opening to the environment such that the lumen is in fluid communication with the at least one opening. Optionally, the pressure sensing mechanism comprises a pressure transducer on-board the distal region, the transducer being adapted for communication with a pressure monitoring system. 
   Thus, the invention relates to a transseptal device configured for decreasing the likelihood of unintentional cardiac injury. The device may comprise a curve at the distal end of the device. The curved region at the distal end of the device is made of an elastic material such that the distal end of the device conforms to an internal lumen of a guiding catheter in order to be advanced through the guiding catheter within the vasculature. The distal end of the device remains inside the guiding catheter while the functional tip is exposed and then positioned against the desired perforation location on the septum. This ensures that the device remains straight while it is being positioned and during perforation. Once the device has perforated the septum, it is advanced out of the guiding catheter and through the perforation. This allows the distal end to take on its natural curve within the left atrium. As a result of the curve the functional tip does not continue to move forward towards the posterior wall of the heart. The functional tip is positioned at the end of the curve, and is unlikely to inadvertently injure other structures within the heart. If the operator inadvertently advances the device beyond the desired location, the curved portion of the device, instead of the functional tip, would contact the posterior wall of the heart. The curved portion is constructed of a material that is unlikely to cause any damage to heart structures. 
   It is to be understood that references to perforate or perforating a material, such as tissue, in relation to the present invention includes puncturing, cutting, ablating, coagulating and removing material. 

   
     DESCRIPTION OF THE DRAWINGS 
     In order that the invention may be readily understood, embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which: 
       FIG. 1  illustrates a schematic view of an electrosurgical system including a preferred embodiment of a transseptal device in accordance with the invention; 
       FIG. 2  illustrates the curve of the transseptal device of  FIG. 1 ; 
       FIG. 3  illustrates a view of the device of  FIG. 1  positioned inside a guiding catheter; 
       FIG. 4  illustrates a view of the transseptal device of  FIG. 1  positioned against an atrial septum; 
       FIG. 5  illustrates a view of the transseptal device of  FIG. 1  after perforating the atrial septum and being advanced into the left atrium; 
       FIG. 6  illustrates an alternate embodiment of the transseptal device in accordance with the invention; 
       FIGS. 7A and 7B  illustrate respectively a side cross-sectional view of the distal and proximal regions of the transseptal device of  FIG. 1 ; 
       FIG. 8  illustrates a cross-sectional view of an alternate embodiment of the transseptal device; 
       FIG. 9  illustrates a side cross-sectional view of a functional tip of the transseptal device of  FIG. 1 ; 
       FIG. 10  illustrates a side cross-sectional view of an alternate embodiment of a distal region of a transseptal device in accordance with the invention; and 
       FIG. 11  illustrates a side cross-sectional view of an alternate embodiment of the distal and proximal regions of a transseptal device. 
   

   It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a preferred embodiment of a transseptal device  100  in accordance with the invention. Transseptal device  100  comprises an elongate member  102  having a distal region  104 , and a proximal region  106 . The Distal region  104  is adapted to be inserted within and along a lumen of a body of a patient, such as a patient&#39;s vasculature, and maneuverable therethrough to a desired location proximate to septal tissue to be cut. 
   The elongate member  102  is typically tubular in configuration, having at least one lumen extending from the proximal region  106  to the distal region  104 . Elongate member  102  is preferably constructed of a biocompatible polymer material that provides column strength. The elongate member  102  is sufficiently stiff to permit a soft guiding catheter to be easily advanced over the transseptal device  100  and through a perforation. Examples of suitable materials for the tubular portion of elongate member  102  are polyetheretherketone (PEEK), and polyimide. In a preferred embodiment, the outer diameter of the tubular portion of elongate member  102  tapers down to connect to the distal region  104 . In alternate embodiments the outer diameter of the elongate member  102  and the outer diameter of distal region  104  are the same. 
   The distal region  104  comprises a functional tip  108 . A preferred embodiment of the functional tip  108  comprises at least one active electrode made of an electrically conductive and radiopaque material, such as stainless steel, tungsten, platinum, or another metal. Distal region  104  defines at least one opening  110  in fluid communication with a main lumen as described further below. Radiopaque markers (not shown) may be affixed to the elongate member  102  to highlight the location of the transition from the distal region  104  to the elongate member  102 , or other important landmarks on the transseptal device  100  such as locations of openings  110 . 
   The distal region  104  is constructed of a softer polymer material than the proximal region  106  so that it is pliable and atraumatic when advanced through vasculature. The material is also formable, so that its shape can be changed during manufacturing, typically by exposing it to heat while it is fixed in a desired shape. In an alternate embodiment, the shape of distal region is modifiable by the operator during use. An example of a suitable material is Pebax (a registered trademark of Atofina Chemicals, Inc.). The distal region  104  comprises a curve  126  such that the distal region  104  curls up inside a patient&#39;s left atrium as the functional tip  108  crosses the patient&#39;s atrial septum. This ensures that functional tip  108  is not in a position to inadvertently injure unwanted areas within a patient&#39;s heart after septal perforation. The curve is further described in following paragraphs. Distal region  104  preferably has a smaller outer diameter than elongate member  102  so that dilation of a perforation is limited while the distal region  104  is advanced through the perforation. Limiting dilation ensures that the perforation will not cause hemodynamic instability once the transseptal device  100  is removed. The outer diameter of distal region  104  will preferably be no larger than 0.035″ (0.897 mm). This is comparable to the distal outer diameter of the transseptal needle that is traditionally used for creating a perforation in atrial septums. The elongate member  102  has a diameter preferably no larger than 0.050″ (1.282 mm), which is also comparable to the transseptal needle dimensions. 
   The proximal region  106  comprises a handle  111 , a hub  112 , a cable  114 , and a connector  116 . The proximal region  106  may also have one or more markings  117  to indicate distances from functional tip  108 , or other important landmarks on the transseptal device  100 . Handle  111  comprises a curve direction or orientation indicator  113  that is located on the same side of the transseptal device  100  as the curve  126  in order to indicate the direction of the curve  126 . Orientation indicator  113  may comprise inks, etching, or other materials that enhance visualization or tactile sensation. Persons of ordinary skill in the art will appreciate that one or more curve direction indicators may be used and that they may be of any suitable shape and size and a location thereof may be varied about the proximal region  106 . 
   The hub  112  is configured to releaseably couple the transseptal device  100  to an external pressure transducer  118  via external tubing  119 . The pressure transducer  118  is coupled to a monitoring system  120  that converts a pressure signal from the pressure transducer  118  and displays pressure as a function of time. Cable  114  is coupled to the connector  116 , which is used to releaseably couple the transseptal device  100  to an energy source such as a generator  122 . 
   The generator  122  is preferably a radiofrequency (RF) electrical generator that is designed to work in a high impedance range. Because of the small size of the functional tip  108 , impedance encountered during RF energy application is very high. General electrosurgical generators are typically not designed to deliver energy in this impedance range, so only appropriate RF generators can be used with this transseptal device  100 . In the preferred embodiment, energy is delivered as a continuous wave at a frequency between about 400 kHz and about 550 kHz. An appropriate generator for this application is the BMC RF Perforation Generator (model number RFP-100, Baylis Medical Company, Montreal, Canada). This generator delivers continuous RF energy at about 460 kHz. A grounding pad  124  is coupled to the generator  122  for attaching to a patient to provide a return path for the RF energy. Other embodiments could use pulsed or non-continuous RF energy, or using RF energy to ionize a conductive medium on top of the target tissue resulting in a low temperature molecular disintegration. This is sometimes referred to as, Coblation (registered trademark of Arthrocare Corporation, Sunnyvale, Calif.). In still other embodiments of the invention, different energy sources may be used, such as microwave, ultrasound, and laser, with appropriate energy delivery coupling devices. 
     FIG. 2  depicts the curve  126  of the preferred embodiment of the transseptal device  100 . Preferably, curve length is approximately 6 cm (about 2.36″) and traverses 270 degrees of the circumference of a circle. The curve  126  directs functional tip away from cardiac structures after septal perforation, decreasing the risk of inadvertent cardiac perforation.  FIGS. 3 ,  4  and  5  depict transseptal device  100  during use. The transseptal device  100  is introduced into patient through a guiding catheter  300 . Distal region  104  is pliable so that the curve  126  straightens out within guiding catheter  300  and takes on the shape of guiding catheter  300  as it is advanced to the atrial septum  302 , as shown in  FIG. 3 . The transseptal device  100  is longer than the guiding catheter  300  so that it may be advanced slightly out of the tip of guiding catheter  300 , exposing functional tip  108 , as shown in  FIG. 4 . Functional tip  108  is positioned against a desired perforation site on atrial septum  302 , and energy is delivered to perforate septum  302 . In the preferred embodiment curve  126  begins 1 cm (about 0.39″) proximal to functional tip  108 , leaving a 1 cm (about 0.39″) distal portion of the transseptal device  100  straight. This ensures that the transseptal device  100  will exit guiding catheter  300  straight, enabling operator to easily position the transseptal device against septum  302 . After the 1 cm (about 0.39″) distal portion of the transseptal device  100  has been advanced out of the guiding catheter  300  and across the atrial septum  302 , distal region  104  exits guiding catheter  300  and establishes its curved shape within left atrium  500 , protecting heart structures from inadvertent injury. In an alternate embodiment, the shape of distal region  104  is modifiable by the operator during use. In this embodiment, distal region  104  is connected to a control (not shown) associated with proximal region  106 . The control is typically a lever attached to a cord extending within the transseptal device and attached to the distal region  104 . When the lever is moved, tension on cord increases or decreases, and alters the shape of distal region. An operator uses the control to position functional tip  108  in a location within the heart such that inadvertent cardiac injury is unlikely. 
   In a further embodiment of a transseptal device  600  as shown in  FIG. 6 , the energy form used to perforate septum  302  is mechanical. In this embodiment, elongate member  602  is preferably made of a very stiff material such as stainless steel, or a shape-memory metal. The transseptal device  600  comprises a lumen connecting distal region  604  to proximal region  606 . Distal region  604  comprises a functional tip  608  configured as a sharp needle tip. When functional tip  108  is in position adjacent septum  302 , perforation is achieved by applying a mechanical force to proximal region  606  to push functional tip  608  to cut the septum  302  and create the desired perforation. Distal region  604  comprises a curved portion  610  made of a super-elastic material to enable the curve to straighten when advanced through a guiding catheter. The super-elastic material is preferably a memory metal such as Nitinol. In this embodiment, the transseptal device  600  is made of one continuous metal tube with a sharpened functional tip  608 . Curved region  610  begins 1 cm (about 0.39″) proximal to the functional tip  608  and continues for approximately 6 cm (about 2.36″). Curved region  610  is preferably ground down to achieve a smaller wall thickness, and its surface about its outer diameter may be etched to increase pliability. The transseptal device  600  is secured in a desired curve shape and exposed to high temperatures to set the desired curve. Proximal region  606  comprises a handle  611  for operator to grip while applying mechanical energy to perforate septum  302 , and a hub  612  to connect a pressure monitor or syringe for fluid injection. 
   Referring to  FIGS. 7A and 7B  a cross-section of proximal  106  and distal  104  regions of the transseptal device  100  is illustrated in accordance with the preferred embodiment of  FIG. 1 . Functional tip  108  comprises an active electrode  700  that is coupled to an electrically insulated conducting wire  702 . Conducting wire  702  is preferably attached to distal region  104  using an adhesive. Alternately, distal region  104  is melted onto insulation  704  on conducting wire  702  to form a bond. 
   Conducting wire  702  carries electrical energy from generator  122  to active electrode  700 . Conducting wire  702  is covered with insulation  704  made of a biocompatible material that is able to withstand high temperatures such as polytetrafluoroethylene (PTFE), or other insulating material. Conducting wire  702  preferably extends through a main lumen  706  of the transseptal device  100  which lumen extends from proximal region  106  to distal region  104 . In an alternate embodiment illustrated in cross-section in  FIG. 8 , an elongate member  801  comprises a main lumen  806  and a separate lumen  800 . Separate lumen  800  contains a conducting wire  802  therein and main lumen  806  is used for aspiration of blood and injection of contrast and other media. This embodiment of elongate member  801  allows a dedicated lumen for each function of the transseptal device  100 . 
   In the preferred embodiment of  FIGS. 7A and 7B , main lumen  706  extends from distal region  106  along elongate member  102  and through distal region  104  of the transseptal device  100 . At least one opening  110  at the distal region  104  provides a pathway between main lumen  706  and the environment surrounding distal region  104 , such as a desired location within a patient&#39;s body. Openings  110  are sufficiently dimensioned to easily aspirate blood and to inject radiopaque contrast to and through main lumen  706 ; however, openings  110  are limited in number and dimension so that they do not compromise the structural integrity of distal region  104 . The location of openings  110  is as close to functional tip  108  as possible so that only a small portion of the transseptal device  100  is required to be proximate to the desired location for the determination of pressure. 
   Hub  112  is configured for releaseably coupling to an external pressure transducer  118 , or a standard syringe. Preferably, hub  112  comprises a female luer lock connection. Hub  112  is coupled to main lumen  706  via tubing  712  to provide a pathway from main lumen  706  to external pressure transducer  118  so that blood pressure can be determined using a method that is known to those of ordinary skill in the art. Conducting wire  702  exits elongate member  102  through an exit point  708 . Exit point  708  is sealed with an adhesive or a polymeric material. Conducting wire  702  is electrically coupled to cable  114  by a joint  710 . This joint can be made by soldering, or another wire joining method known to persons of ordinary skill in the art. Cable  114  terminates with a connector  116  that can mate with either the generator  122 , or a separate extension connector cable (not shown). Cable  114  and connector  116  are made of materials suitable for sterilization, and will insulate the user from energy travelling through the conductor. 
   Elongate member  102  is coupled to tubing  712  at proximal end  714  of member  102 . Tubing  712  is made of a polymeric material that is more flexible than member  102 . A suitable material for tubing is polyvinylchloride (PVC), or another flexible polymer. Tubing  712  is coupled to hub  112 . This configuration provides a flexible region for the user to handle when releaseably coupling external pressure transducer  118 , or other devices to hub  112 . Couplings between member  102  and tubing  712 , and tubing  712  and hub  112  are made with an adhesive such as a UV curable adhesive, an epoxy, or another type of adhesive. 
   A handle  111  surrounds the joint  710  and the proximal end of member  714  in order to conceal these connections. Handle  111  is made of a polymeric material, and is filled with a filling agent  718  such as an epoxy, or another polymeric material in order to hold the cable  114  and the tubing  712  in place. 
   Referring to  FIG. 9  there is illustrated a view of a preferred embodiment of functional tip  108 . Functional tip  108  comprises one active electrode  700  configured in a bullet shape. Active electrode  700  is preferably 0.059″ (0.15 cm) long and preferably has an outer diameter of 0.016″ (0.04 cm). Active electrode  700  is coupled to an end of the conducting wire  702 , also made out of a conductive and radiopaque material. RF energy is delivered through the active electrode  700  to tissue, and travels through the patient to the grounding pad  124 , which is connected to the generator  122 . Alternate embodiments of an active electrode are configured in shapes other than a bullet. These shapes include a spherical shape, a rounded shape, a ring shape, a semi-annular shape, an ellipsoid shape, an arrowhead shape, a spring shape, a cylindrical shape, among others. 
   Referring to  FIG. 10  there is illustrated an alternate embodiment of a functional tip  1008 . Functional tip  1008  comprises one active electrode  1000  in a ring configuration. Conducting wire  1002  is coupled to the active electrode  1000 , and active electrode  1000  is positioned around a perimeter of a single opening  1010  that provides a pathway between main lumen  1006  and a patient&#39;s body. Another similar embodiment to a functional tip comprises an active electrode in a partially annular shape (not shown). In other embodiments (not shown), functional tip comprises multiple electrodes. Such electrodes may operate in a monopolar mode as with the embodiments detailed in  FIGS. 7A ,  7 B and  10 . Otherwise, such electrodes are arranged such that the RF energy is delivered through at least one active electrode at functional tip, and returns to the generator through at least one return electrode at functional tip. The use of an active and a passive electrode on board the transseptal device  100  eliminates the need for a grounding pad  124  to be attached to the patient as is well understood by persons of ordinary skill in the art. 
   In the preferred embodiment, external pressure transducer  118  is releaseably coupled to the transseptal device  100 . Hub  112  is coupled to external tubing  119  that is coupled to external pressure transducer  118  as shown in  FIG. 1 . External tubing  119  is flushed with saline to remove air bubbles. When the transseptal device  100  is positioned in a blood vessel in a body, pressure of fluid at distal region  104  exerts pressure through openings  110  on fluid within main lumen  706 , which exerts pressure on saline in the external tubing  119 , which exerts pressure on the external pressure transducer  118 . The at least one opening  110  and the main lumen  706  provide a pressure sensing mechanism in the form of a pressure transmitting lumen for coupling to pressure transducer  118 . External pressure transducer  118  produces a signal that varies as a function of the pressure it senses. External pressure transducer  118  is also releaseably electrically coupled to a pressure monitoring system  120  that converts the transducer&#39;s signal and displays a pressure contour as a function of time. 
   Referring to  FIG. 11  there is illustrated an alternate embodiment of a transseptal device  1100  that does not use an external pressure transducer  118  as in the embodiment of  FIG. 1 . In the embodiment of  FIG. 11  the pressure sensing mechanism comprises an on-board pressure transducer  1101  coupled by an adhesive to elongate member  1102  at distal region  1104 . Pressure transducer  1101  is configured at distal region  1104  such that pressure close to functional tip  1108  can be transduced. The on-board pressure transducer  1101  is electrically coupled to a pressure communicating cable  1103  to provide power to the pressure transducer  1101  and to carry a pressure signal to proximal region  1106  of the transseptal device  1100 . The pressure communicating cable  1103  terminates in a monitoring system connector  1105  that is configured to be releaseably coupled to a pressure monitoring system  120 . Monitoring system  120  converts the pressure signal and displays pressure as a function of time. In the embodiment of  FIG. 11 , a main lumen is not required for fluid communication with an external pressure transducer. In addition, this embodiment does not require openings at distal region  106  for fluid communication with a main lumen. However, a lumen with openings may be provided for injecting or aspirating fluids, if desired. 
   The present invention thus provides a device that is capable of creating a perforation in the atrial septum while minimizing the risk of inadvertent cardiac injury. The perforation is created by the application of energy to a functional tip on the transseptal device. A preferred means for minimizing the risk of inadvertent injury comprises a curve at the distal end of the transseptal device. In the preferred embodiment, there is at least one opening near the distal region of the transseptal device for blood or other fluid to enter and fill the lumen and exert a measurable pressure on a coupled external transducer. The lumen and opening may also be useful for injecting radiopaque contrast or other agents through the transseptal device. 
   The transseptal device of the invention is useful as a substitute for a traditional transseptal needle to create a transseptal perforation. The transseptal device of the present invention preferably has a soft and curved distal region with a functional tip that uses RF energy to create a perforation across a septum, making the procedure more easily controlled and less operator dependent than a transseptal needle procedure. The soft distal region of the transseptal device reduces incidents of vascular trauma as the transseptal device is advanced through the vasculature. The application of RF energy is controlled via an electric generator, eliminating the need for the operator to subjectively manage the amount of force necessary to cross the septum with a traditional needle. The present invention eliminates the danger of applying too much mechanical force and injuring the posterior wall of the heart. 
   In an alternate embodiment, the transseptal device is a metal needle with a curved distal end. In this embodiment the operator applies mechanical energy to perforate the septum, however because the transseptal device curls in the left atrium the risk of inadvertent cardiac injury is minimized. 
   The preferred embodiment of this invention is intended to be used to create a perforation in the atrial septum of a patient, however it could also be used in other locations within the heart such as the ventricular septum, or one of the valves. In addition, it could be used in other medical applications where a perforation is required. Applications may include perforating through occluded conduits within the body including but not limited to arteries and veins. Alternately, it could be used for perforating through organs in order to gain access to other areas in the body. 
   Although the above description relates to specific embodiments as presently contemplated by the inventors, it is understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein. The embodiment(s) of the invention described above is(are) intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.