Patent Publication Number: US-2006020314-A1

Title: Systems and methods for characterizing leads

Description:
TECHNICAL FIELD  
      Systems and methods for characterizing implantable leads for conducting electrical signals, and, more particularly, systems and methods for characterizing leads that conduct electrical signals to and from the heart.  
     TECHNICAL BACKGROUND  
      Pacemaker leads represent the electrical link between the pulse generator and the heart tissue, which is to be excited and/or sensed. These pacemaker leads include single or multi-conductors that are connected to an electrode in an electrode assembly at an intermediate portion or distal end of a pacing lead. A connector is included at the proximal end to form the electrical connection with the pulse generator, such as a pacemaker. The lead has particular electrical characteristics that are adapted for use with a particular pulse generator and the type of therapy provided by the pulse generator to the heart tissue. Leads are discussed in U.S. Pat. Nos. 6,701,191; 6,672,895; 6,671,560; 6,606,522; 6,584,363; 6,584,362; 6,577,904; 6,574,514; 6,574,512; 6,564,107; and 6,212,434, which are hereby incorporated by reference for any purpose.  
      To implant the lead within the patient, the lead is fed intravenously toward the heart. The lead may be implanted within or travel through complex or tortuous vasculature. The lead may also need to travel through vasculature having increasingly smaller diameters. Accordingly, the lead has particular mechanical characteristics that relate to the lead&#39;s size and flexibility.  
      There is a need for a system to efficiently identify the characteristics of a lead within and between the lead development community, the medical practitioners, sales departments, and the patient community. There exists difficulty in communicating lead characteristics between people involved with leads. There is also a need to standardize the system used to identify leads while minimizing engineering terminology to make the system more acceptable outside the engineering community.  
     SUMMARY  
      Systems and methods for characterizing leads include indicia that represent characteristics of a lead. In an option, the lead is an implantable lead. The indicia are associated with a lead to provide a means of identifying the characteristics of the lead. Characteristics of a lead include operational characteristics of the lead. In an option, the operational characteristics include performance features related to sensing of patient health statistics, delivery of therapeutic signals and/or insertion of the lead into a patient&#39;s body.  
      The lead includes a body and electrical conductor within the body. In an option, the indicia are connected to the body. In an option, the indicia are on the body. In an option, the indicia are covered by a coating. The coating includes therapeutic agent in an option.  
      Several options for the indicia are as follows. The indicia represent at least one mechanical property of the lead. The mechanical property includes at least one of bending stiffness, torsional stiffness, weight, and mass per unit length. The indicia can also represent an electrical property. The indicia include a plurality of alpha-numeric characters, which represent a corresponding plurality of lead characteristics. The indicia include a graphic representation of the characteristics of the lead. The graphic representation includes a grid. The grid is a three-dimensional grid having a plurality of locations each corresponding to a specific characteristic of the lead. The graphic representation includes a bar graph. The bar graph includes a bar representing a lead characteristic variable, and the bar has a height representing a value of the lead characteristic variable. The bar includes shading or coloring representing the lead characteristic.  
      An apparatus of an embodiment includes a display and indicia associated with the display. The indicia represent characteristics of an implantable lead. In an option, the display includes an electronic device. In an option the electronic device includes a computer network. In an option, the computer network includes a unit for entering a request for the indicia, and a server operably connected to the unit and adapted to provide the indicia to the unit. The server is adapted to provide additional data associated with the indicia. In an option, the electronic device includes a computer readable media storing the indicia and data related to the characteristics denoted by the indicia.  
      A method assigns indicia to an implantable lead. The method includes providing characteristics of a lead type, assigning indicia representing the characteristics of the lead type, associating the assigned indicia to leads of the lead type. Several options for the indicia are as follows. Associating indicia includes imprinting the indicia on the lead. Associating indicia includes attaching the indicia to the lead. Assigning indicia includes assigning an alpha-numeric code for the indicia. Associating indicia includes storing the indicia in a computer readable media. Associating indicia includes providing access to the computer readable media. Providing access to the media includes providing access to the indicia through a computer network. Associating indicia includes storing additional data relating to the indicia and the lead type in the computer readable media. Providing access to the media includes requesting the user to select the indicia before providing access to the additional information.  
      The indicia system and method provides a user, such as a physician, with an readily understood indicator of how a lead will react during insertion into a patient. In an option, the indicia system will provide the user with an understanding of the physical characteristics of the lead. This information allows a user to determine if the correct lead is being used so that the patient receives the proper lead and the physician is implanting a lead that has the favorable characteristics for the patient physiology and physician preferences.  
      This Summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which are not to be taken in a limiting sense. The scope of the present invention is defined by the appended claims and their equivalents. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagram illustrating a lead system constructed according to one embodiment.  
       FIG. 2  is an enlarged, partial view of a lead according to one embodiment.  
       FIG. 3  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 4  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 5  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 6  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 7  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 8  is an enlarged partial view of a lead according to one embodiment.  
       FIG. 9  is a schematic view of a system according to one embodiment. 
    
    
     DESCRIPTION OF THE EMBODIMENTS  
      The following detailed description of the present invention refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope is defined only by the appended claims, along with the full scope of legal equivalents to which such claims are entitled.  
      An implantable system  100  including an electrical stimulator  105  is illustrated in  FIG. 1 . It should be noted that the system  100  is suitable for use with implantable electrical stimulators, such as, but not limited to, pulse generators, neuro-stimulators, skeletal stimulators, central nervous system stimulators, or stimulators for the treatment of pain. The implantable device  100  includes an implantable lead  107  that includes body  110  and at least one elongate conductor  120  extending within the lead body  110 . The lead body  110  typically surrounds the conductor  120  to insulate the conductor from the surrounding environment, such as tissue, and to target any electrical signal to or from a specific location of a person&#39;s body. The lead  107  extends from a proximal end  112  to a distal end  114 . The proximal end  112  of the lead is electrically coupled with the electrical stimulator  105 , for example, with a connector. Lead  107  is adapted to carry various signals associated with sensing and therapy for cardiac pacing and defibrillation, for example, bradycardia, tachycardia, tachyarrhythmia, and left ventricular pacing.  
      In an embodiment, the electrical stimulator  105  is adapted to be implanted with a person&#39;s body and thus the entire device  100  is adapted to be implanted in a person&#39;s body. In one option, the electrical stimulator  105  is a pulse sensor and generator that contains electronics to sense various electrical signals of the heart and also produce current pulses for delivery to the heart. The pulse sensor and generator also contains electronics and software necessary to detect certain types of health problems, such as arrhythmias, and to provide therapies for them.  
      The implantable device  100  further includes, in one option, one or more electrodes  115 . The one or more electrodes  115  are each electrically coupled with the conductor  120 , which in turn electrically couples the electrode  115  to a signal generation circuit or a detection circuit in implant  105 . The electrode  115  allows for electrical signals to be delivered to the tissue from the electrical stimulator  105 . The implantable device  100  further includes, in one option, features to allow the lead body to be fixated within a patient. For example, in one option, the lead body includes passive fixation features, such as one or more tines. In another option, the lead body includes an active fixation assembly, such as a fixation helix.  
      Indicia  125  are associated with the lead  107 . The indicia  125  provide an indicator of the characteristics and/or properties of the lead  107 . Examples of lead characteristics include, but are not limited to, stiffness, weight, length, diameter, electrical capacity, lubricity, or coating type. Other lead characteristics are fixation features. Stiffness includes, but is not limited to, torsional stiffness and bending stiffness. Electrical capacity includes, but is not limited to, impedance. Coating type includes, but is not limited to, medications or biomedical coatings that provide further therapy to the person receiving the implant. Mass per unit length is a further lead characteristic. Lubricity is a further lead characteristic. Pushability of over-the-wire leads is a further lead characteristic. In an option, the indicia  125  are positioned on an outer surface of lead body  110 . Lead  107  may include a covering, which is inert with respect to the environment in which it is implanted, over the indicia  125 . The covering does not interfere with the indicia&#39;s ability to convey information regarding the characteristics of the lead. In an option, the covering is transparent over the indicia  125 . In an option, indicia  125  are removably attached to the lead  107 . In an option, indicia  125  are displayed on materials describing or promoting lead  107 .  
      In the embodiment shown in  FIG. 1 , there is a plurality of indicia  125 . Each indicia  125  is the same when the indicia represent characteristics of the whole lead  107 . That is the indicia  125  denotes a composite performance grade indicating the operational characteristics of the entire lead. In another option, indicia  125  represent characteristics of portions of lead  107 . That is, the left indicia as shown in  FIG. 1  represents characteristics of the left portion of lead  107 , e.g., to the left of the break line remote from the signal generator/signal analysis device  105 . The right indicia as shown in  FIG. 1  represents characteristics of the right portion of lead  107 , e.g., to the right of the break line adjacent the signal generator/signal analysis device  105 .  
       FIG. 2  shows an enlarged, partial length of lead  107 A including lead body  110  and conductor  120 . Indicia  125 A are associated with lead  107 A. The same elements throughout the figures of the present application are designated by the same reference number. In some embodiments, alphabetic characters are added as suffixes to the reference numbers thereby delineating between the figures. Indicia  125 A include a plurality of alpha-numeric characters  131   1 ,  131   2 , . . .  131   N . Each character  131   1 ,  131   2 , . . .  131   N  represents one characteristic of the lead  107 A. At least one characteristic is a variable. The value of the characters  131   1 ,  131   2 , . . .  131   N  are selected to represent the specific ones of the variable characteristics. In an embodiment, there are three characteristics that are being indicated by indicia  125 A. The first character  131   1  represents bending stiffness of the lead  107 A. In this example, bending stiffness is a lead variable that has two potential values, low and high. First character  131   1  accordingly has two different potential values representing low and high respectively. First character  131   1  is a one for low or a two for high in an embodiment. First character  131   1  is the alphabetic character “L” for low or the alphabetic character “H” for high in an embodiment. Other representative characters may be selected to represent these characteristics and are within the scope of embodiments of the present invention. The second character  131   2  represents the weight of the lead  107 A. In this example, weight is a lead variable that has five potential values over a range. Second character  131   2  accordingly has five different potential values representing a value in the weight range. Second character  131   2  is selected from a group that represents the range of five values. In an embodiment, the group consists of the numeric characters “1”, “2”, “3”, “4”, and “5”. The third character  131   3  represents the torsional stiffness of the lead  107 A. In this example, torsional stiffness is a lead variable that has three potential values over a range. Third character  131   3  is selected from a group that represents the range of three values. In an embodiment, the third character group consists of the numeric characters “1”, “2”, or “3”. In an option, the indicia  125 A would be displayed as H-5-1. Such indicia represent high bending stiffness, the heaviest lead, and the lowest torsional stiffness. While these examples describe bending stiffness, weight, and torsional stiffness, it will be recognized that The indicia described herein are adaptable to other unique physical characteristics of a lead.  
       FIGS. 3 and 4  show an enlarged, partial length of lead  107 B including lead body  110  and conductor  120 . Indicia  125 B are associated with lead  107 B. In an option, indicia  125 B include alpha-numeric characters representing characteristics of lead  107 B as described herein. The indicia  125 B are displayed on a base  135 . In an option, base  135  is printed material on which indicia  125 B are shown and visible to a user. An attachment device  137  secures base  135  to the lead body  110  as shown in  FIG. 3 . Attachment  137  is a plastic strip or fiber device that ties to lead body  110 . Attachment  137  is removed before implant of the lead  107 B into a patient.  FIG. 4  shows the base  135  associated with the lead  107 B without an attachment. The base  135  provides a user with the indicia  125 B, which convey the characteristics of the lead  107 B to the user, e.g., the medical personnel.  
       FIG. 5  shows an enlarged, partial length of lead  107 C including lead body  110 , conductor  120  and indicia  125 C. Indicia  125 C include a grid that has, in an option, horizontal and vertical lines to define areas  141 - 146  in the grid. The areas  141 - 146  within the grid are selectively darkened or colored to indicate the properties of the lead. The grid is read vertically in an embodiment to define three features of the lead  107 C, i.e., vertically aligned area pairs  141 / 142 ,  143 / 144 , and  145 / 146  indicate the value of one feature, respectively. In an option the areas  141 - 146  each have two possible values. Accordingly, each area pair has four possible values with the areas  141 - 146  either being undarkened, i.e., a zero value, or darkened, i.e., a one value, in a binary system. In the illustrated example of  FIG. 5 , the first feature of lead  107 C is indicated with pair  141 / 142  having area  141  darkened and area  142  undarkened, i.e., a 01 value. The second feature of lead  107 C is indicated with pair  143 / 144  having area  143  undarkened and area  144  darkened, i.e., a 01 value. The third feature of lead  107 C is indicated with pair  145 / 146  having areas  145  and  146  undarkened, i.e., a 00 value. In an option, the areas  141 - 146  are cross-hatched to indicate a value of a lead characteristic. In an option, the areas  141 - 146  are colored to indicate a value of a lead characteristic. In an option, each of areas  141 - 146  represents a binary value for six different lead characteristics.  
       FIG. 6  shows an enlarged, partial length of lead  107 D including lead body  110 , conductor  120  and indicia  125 D. Indicia  125 D include a graph that has a plurality of vertical segments  151   1 ,  151   2 , . . .  151   N . Each of the segments  151   1 ,  151   2 , and  151   N  are selectively darkened or colored to indicate a characteristic of the lead  107 D. The characteristics of lead  107 D are denoted by the combination of vertical segments  151   1 ,  151   2 , and  151   N .  
       FIG. 7  shows an enlarged, partial length of lead  107 E including lead body  110 , conductor  120  and indicia  125 E. Indicia  125 E include a graph that has, in an option, a plurality of vertical segments  161   1 ,  161   2 , and  161   N . Each of the segments  161   1 ,  161   2 , and  161   N  are respectively set at a height to indicate a characteristic of the lead  107 E. In an option, the height of at least one of segments  161   1 ,  161   2 , and  161   N  indicates a particular value of a characteristic of lead  107 E. For example, indicia  125 E indicates the following characteristics by segment: the first segment  161   1  indicates the type of connector on lead  107 E; the second segment  161   2  indicates the weight of lead  107 E; and the third segment  161   N  indicates the stiffness of lead  107 E. Other characteristics of a lead are illustratable using similar and/or additional segments.  
       FIG. 8  shows an enlarged, partial length of lead  107 F including lead body  110 , conductor  120  and indicia  125 F. Indicia  125 F includes a three dimensional graphic extending in X, Y, and Z directions and has three visible surfaces. Each of the three visible surfaces is divided into distinct parts or surface portions  171   1 ,  171   2 ,  171   3 , . . .  171   N . Each surface portion  171   1 ,  171   2 ,  171   3 , . . .  171   N  is adapted to indicate characteristics of lead  107 F. In the illustrated embodiment, a single surface portion  171   1  indicates the characteristics of lead  107 F. In an option, a plurality of surface portions is shaded to designate lead characteristics. For example, each side of the indicia  125 F is dedicated to one characteristic and at least one of the plurality of surface portions on a specific side indicate a specific value of the lead characteristic associated with that specific side.  
      The above description provides exemplary embodiments for conveying information regarding characteristics of an implantable lead for medical applications. There remains a need for an effective system to disseminate the definitions of the indicia. That is, some of the indicia described may not be readily understood by users of this information conveying system until indicia are widely accepted into standard practice.  
       FIG. 9  shows an embodiment of system  200  for conveying information to familiarize a user with regard to the meaning of the indicia. System  200  includes a central information system  202  connected over a network  204 , such as an electronic or computer network, to a first interface device  206  and a second interface device  208 . The computer network  204  is a global computer network, such as the internet, in an embodiment. The computer network  204  is a wide area network (WAN), local area network (LAN) or other similar network in an embodiment. Computer network  204  includes a wireless network in an embodiment. Information system  202  is adapted to communicate with the interface devices  206  and  208  through the network  204 . Such communication requires a communications interface between the components of system  200 . Examples of a communication interface include protocols such as File Transfer Protocol (FTP) and other network communication standards such as html, xml, or other codes compatible with network interfaces such a web browsers (Internet Explorer, Netscape, etc.). The communications over the computer network can be made using known secure means such as using the Secure Sockets Layer (SSL) Protocol or using other forms of encryption. Interface devices  206  and  208  each include a network input/output unit to allow the interface device to communicate with the network  204 . The network input/output units may not be the same in each interface device. Accordingly, the first interface device  206  may be a personal computer connected to the internet through a modem. The second interface  208  device may be a portable electronic device such as a mobile telephone of personal data assistant. Interface devices  206  and  208  further include user input/output devices such as keyboards, number pads, view screens, and other typical devices.  
      System  202  includes a central database  210  that stores data related to the indicia for lead characteristics. The data includes the code and/image of the indicia and specific data related to the lead as indicated by the indicia. In an option, the specific data includes a detailed specification list of the lead. In an option, the specific data includes manufacturing data. In an example, the indicia  125 A are associated with a lead to denote its characteristics. The central database  210  stores the indicia value and the lead characteristics represented by each specific indicia. In a further example, one of the graphic indicia  125 C- 125 F is used to denote lead characteristics. Central database  210  stores each graphic indicia and lead characteristics denoted by indicia. System  202  further includes a database server  212  to provide access to the central database  210 . The database server  212  in an embodiment use Microsoft (Trade Mark) SQL Server  2000 . Database server  212  communicates through a web server  214  and firewall  216  with the computer network  204 . The web server  214  is an Apache web server running Perl scripts and JavaScript and use stored static HTML templates and dynamic page generation code. The Apache servers also use Mason (Trade Mark) to allow mix of Perl and HTML to be used.  
      In use, system  200  allows a user through interface devices  206  and  208  to access data that explains the indicia  125 A- 125 F. A user accesses the central information system  202  for example by visiting a web page or logging into a private computer network. The user may enter the indicia into an input of the central information system  202 , which will in turn display or download data related to the lead identified by the indicia. If the indicia are a graphic, then the central information system  202  may provide a menu, icons, or thumbnail of all indicia for the users to choose from. The user will select at least one of the indicia for to access additional data. Selection is made by clicking on the menu item, icon, or thumbnail. Selection can be further automated such that data is displayed as the user passes a cursor over one of the menu items, icons, or thumbnails. The central information system further includes a contact interface that allows the user to contact support or sales personnel through voice or email.  
      Central information system  202  is stored on a computer readable medium in an option. The computer readable medium includes read only memory, random access memory, static memory, EEPROM, optically read memory, compact disks, DVD formatted disks, magnetic media, and other computer readable medium known in the computer readable media art. When the central information system  202  is stored on portable computer readable media, then the data associated with the indicia  125 A- 125 F can be taken to and left with users so that a user need not access central information system  202  through computer network  204 .  
      Advantageously, the system described herein allows a user, such as a physician, research and developer, marketer, etc., to effectively communicate regarding lead characteristics. The characteristics relate to the lead, per se. Such characteristics relate to implantation of the lead in a patients body and include diameter, length, stiffness, lubricity, and pushability, which are directly related to inserting the lead into a patient&#39;s body. Other characteristics related to the lead include electrical characteristics. Once the system described herein users of leads will be able to accurately communicate their needs and preferences with regard to leads so that patients receive improved products and care.  
      It is to be understood that the above description is intended to be illustrative, and not restrictive. It will be understood that the examples and illustrations described herein are adaptable to any characteristic of a lead in need of description to facilitate communication of a lead&#39;s characteristics. Although the use of the implantable device has been described for use as a lead in, for example, a cardiac stimulation system, the implantable device could as well be applied to other types of body stimulating systems. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.