Abstract:
A dongle couples an electrophysiologic catheter and a navigational system, including a patient interface unit (PIU). The dongle permits hardware normally carried on catheter control handle to be relocated onto the dongle to render catheter “greener” and less costly to manufacture use. The dongle having a support portion with flexibility, shape memory and/or varying degrees of stiffness also advantageously allows a user more control over the placement, position and orientation of the dongle. The dongle has a body with a first electrical interface unit, and a support portion with a second electrical interface unit, the support portion having an outer flexible tubular member with shape memory. In one embodiment, the support portion comprises a gooseneck tubing. In another embodiment, the support portion comprises a coiled spring.

Description:
FIELD OF INVENTION 
     The present invention relates to a dongle for coupling an electrophysiologic catheter with a patient interface unit. 
     BACKGROUND OF INVENTION 
     Catheterization is used in diagnostic and therapeutic procedures. For example, a cardiac catheter is used for mapping and ablation in the heart to treat a variety of cardiac ailments, including cardiac arrhythmias, such as atrial flutter and atrial fibrillation which persist as common and dangerous medical ailments, especially in the aging population. Diagnosis and treatment of cardiac arrhythmias include mapping the electrical properties of heart tissue, especially the endocardium and the heart volume, and selectively ablating cardiac tissue by application of energy. Such ablation can cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions. Various energy delivery modalities have been disclosed for forming lesions, and include use of microwave, laser and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall. In a two-step procedure—mapping followed by ablation—electrical activity at points within the heart is typically sensed and measured by advancing a catheter containing one or more electrical sensors (or electrodes) into the heart, and acquiring data at a multiplicity of points. These data are then utilized to select the endocardial target areas at which ablation is to be performed. 
     Electroanatomical navigation systems (ENS) are used in conjunction with cardiac diagnostic and therapeutic catheters. One such system is CARTO available from Biosense Webster of Irwindale, Calif., which is a 3-D mapping system that provides electrophysiologists with magnetic location technology and visualization data of catheter tip and curve location, anatomical mapping with rapid creation of high-resolution, CT-like maps, and a patient interface unit (PIU) as a central connection for catheters and equipment. 
     Catheters for use with navigation systems have control handles which carry hardware, such as one or more printed circuit boards (PCB). For example, where electromagnetic sensor location data is transmitted via a sensor cable extending through the catheter, one or more circuit boards housed in the control handle may amplify the signals and convert them to a computer readable form before the data is transmitted to a signal processing unit of the navigation system. Although catheter handles are costly, catheters are not easily sterilized so they are intended for single use only and are discarded along with their hardware/metal bearing handles. 
     Dongles are known. They are pieces of hardware that attach to a computer or other electronic device and enable additional functions. Dongles typically include at least one interface plug for connection to the computer or other electronic device to enable electrical connection with the same. The dongle may include a flexible cable with a second interface plug. 
     With rising medical costs and the move toward more environmentally-friendly (“greener”) catheters, current catheters are designed with the desire to relocate electronic hardware from the control handles to elsewhere in the PIU or other components of the navigation system. Some hardware may be relocated to a temporary location, such as a dongle, before finding a more permanent location within the navigation system. In that regard, a free-hanging dongle or a dongle with a flexible cable can be difficult to manage, especially as more dongles are used to temporarily house more components. A free-hanging dongle or one with a flexible cable may be prone to damage if knocked or bumped against other equipment and cause additional tension on any extension cable between the dongle and the catheter. Moreover, a free-hanging dongle or one with a flexible cable may be a nuisance to users who resort to using tape or zip-ties to secure or position them. 
     Accordingly, there is a desire for a catheter dongle with a stiffening member that would enable a user to better position and secure the dongle. There is also a desire for a catheter dongle that is more durable and less prone to damage from accidental bumping and adding stress or tension to catheter extension cables. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a dongle for coupling an electrophysiologic catheter and a navigational system, including a patient interface unit (PIU). The dongle permits some of the hardware normally carried on the catheter control handle to be relocated so that the catheter—normally intended for single use—is less costly to manufacture and contain less waste when discarded. The dongle having a support portion with flexibility, shape memory and/or varying degrees of stiffness also advantageously allows a user more control over the placement, position and orientation of the dongle. The support portion protects both the dongle body, as well as the catheter and the PIU by providing elastic displacement for shock absorption where the dongle or the catheter are accidentally bumped. The support portion also decreases the amount of stress and tension imposed on any extension cable that is connecting the catheter to the dongle. 
     In one embodiment, the dongle has a body with a first electrical interface unit, and a support portion with a second electrical interface unit, the support portion having an outer flexible tubular member with shape memory. In one embodiment, the support portion comprises a gooseneck tubing. In another embodiment, the support portion comprises a coiled spring. 
     In a more detailed embodiment, the electrical interface unit may comprises an electrical connection port or an electrical plug adapted to transmit electrical signals, where the electrical signals may comprise electrical signals are representative of electrical activity in a patient&#39;s body, position data of a distal portion of the catheter within a patient&#39;s body, and/or RF energy. 
     In a more detailed embodiment, the body of the dongle houses components that may be typically found in a catheter control handle, such as electronic hardware, including printed circuit boards which may be used to process electrical signals representative of position data of a distal portion of the catheter within a patient&#39;s body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is pictorial of a catheter-based electroanatomical navigation system using a dongle, in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic pictorial of the catheter-based electroanatomical navigation system of  FIG. 1 , in use in a cardiac procedure. 
         FIG. 3  is a side cross-sectional view of a catheter control handle, in accordance with an embodiment of the present invention. 
         FIG. 4  is a side cross-sectional view of a dongle, in accordance with an embodiment of the present invention. 
         FIG. 5  is a side view of one embodiment of a flexible cable or gooseneck, shown partially broken away. 
         FIG. 5A  is an enlarged detailed view of a portion of the flexible cable of  FIG. 5 . 
         FIG. 6  is a side cross-sectional view of another embodiment of a flexible cable or gooseneck. 
         FIG. 7  is a side view of a dongle in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIG. 1 , a catheter-based electroanatomical navigation system  10  is shown for use with a catheter  40 , an extension cable  41  and a dongle  42 , in accordance with the present invention. The system  10  includes at least one monitor  12 , a patient interface unit (PIU)  14 , a location pad  16 , a signal processing unit  20 , an ablation energy generator  22 , a workstation  24  and a printer  26 . The monitor  12  displays patient data and maps. The PIU  14  allows cable connections between the signal processing unit  20  and all other system components. The location pad  16  is for placement under a patient lying on a patient table  18 , enabling accurate detection of catheter location. The signal processing unit  20  determines all location and performs ECG calculations. The generator  22  may be an RF generator for supplying RF energy to the catheter. The workstation  24  is a computer adapted for storing patient data and maps. The printer  26  is provided to print color maps produced by the system  10 . As shown in  FIGS. 1 and 2 , the dongle  42  extends between PIU  14  and the catheter  40 , providing an electrical connection and performing any function(s) used or necessary for data gathered and transmitted by the catheter to be understood and processed by the system  10 . Accordingly, the PIU  14  includes at least one electrical connection interface, for example, port  30  configured to interface with the catheter  40  via the dongle  42 . 
     In one embodiment, the catheter  40  has an elongated catheter body  112 , a distal section  114  carrying tip and/or ring electrodes  117  and a control handle  116 . As shown in  FIG. 3 , lead wires  140  are connected to the electrodes  117  for receiving and transmitting electronic signals for generating patient data, including 3-D anatomical maps of the patient&#39;s heart and ECG readings which are displayed on the monitor  14  and stored in the workstation  24 . Moreover, electromagnetic position sensor(s) carried in the distal section  114  are responsive to external magnetic fields generated by the location pad  16  below the patient table  18  for generating electrical signals representative of the location of the distal tip section. Sensor cables  132  are connected from the position sensors to transmit these signals. Both the lead wires  140  and the sensor cables  132  extend through the length of the catheter, passing through the distal tip section  114 , the catheter body  112  and the control handle  116 . In that regard, a proximal end  116 P of the control handle has at least one electrical connection port  30  to enable electrical connection with the lead wires  140  and sensor cables  132 . 
     In one embodiment, the extension cable  41  between the catheter  40  and the dongle  42  has a proximal end  41 P and a distal end  41 D, as shown in  FIG. 2 . The distal end  41 D is provided with a first interface, for example, plug  43  configured to be received in the electrical connection port  30  at the proximal end  116 P of the control handle. The proximal end  41 P is provided with a second interface, for example, plug  44  configured to be received in an electrical interface, for example, port  45  provided in a distal end of the dongle  42 . 
     In one embodiment, the dongle  42  has a proximal support portion including a semi-rigid dongle cable  53 , and an elongated distal body or housing  54  with a proximal end  54 P, a distal end  54 D and a generally sealed interior cavity extending therebetween, as shown in  FIG. 4 . At the distal end  54 D, the electrical port  45  is configured to receive the second interface plug  44  of the extension cable  41 . At a proximal end of the cable  53 , an electrical interface, for example, plug  55  is configured to be received in the electrical port  30  of the PIU  14 . 
     In the illustrated embodiment of  FIG. 4 , the dongle  42  houses hardware, for example, at least one printed circuit board (PCB)  60  which receives the electrical signals representative of catheter location transmitted by the sensor cables  136  to through the extension cable. The PCB  60  may amplify the signals and convert to a form readable by the signal processing unit  20  of the system  10  which are then transmitted via the proximal dongle cable  53 . 
     With reference to  FIGS. 5 and 6 , the proximal cable  53  has an elongated flexible outer tubing member  62  defining a lumen  63  through which dongle wires  64  extend between the proximal and distal ends of the cable. In accordance with a feature of the present invention, the cable  53  is semi-rigid with shape memory so that the cable can be manipulated and configured by a user to selectively position or orient the dongle body  54  as desired. In one embodiment, the outer tubing member  62  comprises spirally wound flat strip(s)  67  of metal, metal alloy or generally rigid plastic material with longitudinal folds  69 , interlocking adjacent longitudinal side edges  71  to form what is commonly referred to as a “gooseneck” tubular structure with a corrugated-like profile which provides flexibility and shape memory such that it can be manipulated into and retain a variety of desired configurations. The tubular structure may also act as a strain relief and/or a trunk cable insulation covering. The wires  64  extending through the tubing member  62  are protected and sealed within the tubing member  62 . 
       FIG. 6  illustrates another embodiment of a flexible cable or gooseneck tubular structure comprising an inner coiled spring  80  and an outer sectional wire  82  wrapped around the coiled spring  80 . In the illustrated embodiment, the underlying wire of the spring  80  has a circular cross-section and the outer sectional wire  82  has a triangular cross-section, wherein the underlying wire of the spring  80  is nested between two inner vertices V of adjacent pairs of sectional wires  82 . 
     In use, the dongle  42  is connected to the PIU  14  via the connector plug  55  being received in the connector port  30 , as shown in  FIG. 2 . A distal end of the dongle  42  receives the proximal connector  44  of the extension cable  41 . The distal connector  43  of the extension cable  41  is received in the connector port  30  of the control handle  116 . In a diagnostic procedure, as electrical signals are sensed by the tip and ring electrodes  117  on the distal tip section  114  of the catheter  40  positioned in patient&#39;s heart  125 , the signals are transmitted via the lead wires  114  through the distal tip section  114 , the catheter body  112  and the control handle  116 . The signals are transmitted from the control handle  116  to the PIU  14  for processing by the signal processing unit  20  by the extension cable  41  and the dongle  42 . In a therapeutic procedure, RF energy from the RF generator  22  of the system  10  is delivered to the tip and ring electrodes  117  via the PIU  14 , the dongle  42 , the extension cable, and the lead wires  140  extending through the control handle  116 , the catheter body  112  and the distal tip section  114 . 
     For position sensing of the catheter distal tip section  114  in the heart  125 , electrical signals from the position sensors carried in the catheter distal tip section are transmitted via the sensor cables  132  which extends from the distal tip section, to the catheter body  12 , and the control handle  116 . The signals are further transmitted via the extension cable  41  to the dongle  42  which provides the PCB  60  that may amplify and/or convert the signals before transmitting them to the PIU  14  for processing by the signal processing unit  20  of the system  20 . 
     Accordingly, the dongle of the present invention renders a catheter more disposable and “greener” by allowing expensive and metal-bearing hardware to be relocated from the catheter and onto the dongle. Moreover, the semi-rigid dongle of the present invention reduces the risk of damage to the dongle, the catheter and the navigation system by allowing the user more selection in the placement and positioning of the dongle. 
     In an alternate embodiment as shown in  FIG. 7 , a dongle  42 ′ is illustrated with a proximal support portion including a semi-rigid dongle arm  66  whose proximal end carries the electrical plug  55 . The arm  66  comprises a tightly coiled spring whose diameter may vary or be uniform throughout the length of the arm. The wires  64  extending through the spring are protected by the spring. The spring may be manufactured with different degrees of stiffness depending on the use and application, and be provided with a preformed shape. In the disclosed embodiment, the spring has sufficient stiffness to support the dongle body in a horizontal position but allows elastic bending or displacement where the dongle body is accidentally bumped. 
     It is understood by one of ordinary skill in the art that the body of the dongle may house a variety of electrical hardware for receiving and processing (including, for example, amplifying, converting, digitizing, etc.) a variety of electrical signals (including, for example, optical, audio, etc.) between the catheter and the navigation system, as needed or appropriate. 
     The preceding description has been presented with reference to presently preferred embodiments of the invention. Workers skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structure may be practiced without meaningfully departing from the principal, spirit and scope of this invention. In that regard, the drawings are not necessarily to scale. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and illustrated in the accompanying drawings, but rather should be read consistent with and as support to the following claims which are to have their fullest and fair scope.