Abstract:
A lockout connector arrangement for implantable medical devices having at least one port for receiving a non-cardiac lead connector selectively permits only certain electrical leads to be connected to the implantable medical device. A lead connector pin of a non-cardiac lead connector is specially designed to be larger than a DF-1 lead connector pin, but smaller than an IS-1 lead connector pin. A corresponding header of implantable pulse generator has a connector port for a non-cardiac lead with a proximal-most portion that is larger than the DF-1 lead connector pin, but smaller than the IS-1 lead connector pin; and otherwise generally consistent with the other dimensions of an ISO standard IS-1 pacemaker lead connector.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     The present application is a non-provisional of U.S. Patent Application Ser. No. 60/584,647 (Attorney Docket No. 021433-001400US), filed Jun. 30, 2005, the full disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to implantable electrical medical devices used to stimulate the heart, other tissue, and nerves, to control the functioning of the particular organ or bodily function. More particularly, the present invention is directed to electrical lead connector arrangements for implantable medical devices that selectively permit only certain electrical leads to be connected to the implantable medical device.  
         [0004]     2. Background of the Invention  
         [0005]     Implantable pulse generator medical devices are well known in the art, and include medical devices such as pacemakers, defibrillators, baroreflex activation devices and muscle and nerve stimulators. Generally, these medical electrical devices comprise an implantable pulse generator unit and an electrical lead or leads connected to one or more electrodes. The electrode may be placed adjacent to a particular part of the human body, such as within the myocardial tissue of the heart, within a vein or proximate any other tissue to be stimulated and/or sensed. The electrode, which is attached at the distal end of the lead, is attached to the appropriate location in the human body, and the proximal end of the lead is connected to a lead connector assembly of the implantable pulse generator. The lead connector assembly, sometimes referred to as a header, enables the lead to be mechanically and electrically connected to circuitry within the implantable pulse generator.  
         [0006]     The header of an implantable pulse generator typically has a plurality of connector ports to which a plurality of leads may be connected. For pacemakers and defibrillators, these connector ports are either high voltage ports for receiving high voltage electrical lead connectors of a defibrillation electrode or low voltage connector ports for receiving electrical lead connectors of a sensing/pacing electrode. For other types of tissue stimulation devices, the connector ports are typically low or moderate voltage connector ports for receiving electrical lead connectors to connect to tissue sensing and/or stimulation electrodes.  
         [0007]     For implantable pulse generators having a plurality of ports and a plurality of leads, it is possible for a particular lead to be inserted into an improper port. If this were to happen, the delivery of stimulation pulses through an improperly connected lead would not provide the intended therapy and could be potentially damaging or fatal to a patient. A non-cardiac stimulation lead connected to a pacing port would likely deliver an ineffective therapy, and could even have the dramatic consequence of inducing fibrillation in the patient; however, the non-cardiac stimulation lead most likely would not be damaged due to the relatively low voltage of the pacing stimulation pulses. A potentially more dangerous situation would arise if a low or moderate voltage lead were to be connected to a connector port for a high voltage defibrillation electrode. Not only would the unintended delivery of a high voltage defibrillation shock of up to 750 V through a pacing or stimulation electrode designed for voltages of less than 5 V likely cause damage to that low or moderate voltage electrical lead, the consequences for the unintended delivery of such a shock could be damaging or even fatal to a patient, even if fibrillation were not induced as a result of the shock.  
         [0008]     To prevent defibrillator leads and pacer leads from being connected to the improper port, the International Standards Organization (ISO) developed standards for the pacer lead connector and the pacer port or cavity, as well as standards for the defibrillator lead connector and defibrillator port or cavity. The standard for the defibrillator connector and cavity is ISO 11318 and the standard for the pacemaker connector and cavity is ISO 5841-3, both of which are incorporated herein by reference. The standard pacer port is referred to as an IS-1 port and the standard defibrillator port is referred to as a DF-1 port. If the ISO standards are followed for these structures, then a lead made in accordance with one of the standards cannot be connected to a port constructed in accordance with the other of the standards. Hence, a pacer lead made according to the ISO standard (5841-3) will not be able to be connected to a defibrillator lead connector that was made according to the ISO standard (11318). The details of these ISO standards are hereby incorporated by reference.  
         [0009]     Although the ISO standards provide guidance for defibrillators and pacers to ensure that the lead connectors cannot be operably connected to the improper port in these two types of implantable medical devices, the problem of how to avoid similar improper connections for other types of tissue stimulation leads is not addressed.  
         [0010]     U.S. Pat. No. 6,044,302 describes a multiport header arrangement for a cardiac rhythm management device includes at least one standard port and a separate port for a left ventricular access lead. The left ventricular access lead can only be electrically and mechanically coupled to the proper port. Standard IS-1 and DF-1 leads cannot be electrically or mechanically coupled to the port for the left ventricular access lead. The lockout solution described in this patent requires the left ventricular access lead to have a smaller diameter than either the IS-1 or DF-1 leads so that the larger leads will not fit in the smaller connector port. The patent requires the physician to realize that the smaller left ventricular access lead has been improperly inserted into a larger IS-1 or DF-1 port because of the difficulty in locking down the smaller diameter lead connector with a set screw that secure the lead connector into the port.  
         [0011]     U.S. Pat. No. 6,705,900 describes an improved connection system for coupling a device such as a pacemaker, cardioverter, defibrillator, nerve stimulator, muscle stimulator, implantable monitor or other medical device to a medical lead that features a coupling member, which includes an inner lumen sized to form a press fit around the proximal end of the lead body and has connector means to enable a connector pin at the proximal end of the lead to mechanically and electrically couple to a device. While this system provides a solution for adapting one type of lead to be used in a different type of connector port, it does not provide a solution to the problem of improperly inserting one type of lead in a different type of connector port.  
         [0012]     Although existing standards have worked well for addressing the problems of proper connection of leads to implantable pulse generators for cardiac stimulation devices, there is a need for a more general solution for addressing the problems of proper connection of leads to implantable pulse generators for other types of tissue stimulation devices.  
       BRIEF SUMMARY OF THE INVENTION  
       [0013]     The present invention is a lockout connector arrangement for implantable medical devices having at least one port for receiving a non-cardiac lead connector that selectively permits only certain electrical leads to be connected to the implantable medical device. Specifically, a lead connector pin of a non-cardiac lead connector is specially designed to be larger than the lead connector pin of a DF-1 defibrillation lead connector port, but smaller than the lead connector pin of an IS-1 pacemaker lead connector port. A corresponding header is provided for an implantable pulse generator in which a connector port for a non-cardiac lead has a proximal-most portion that is larger than the lead connector pin of a DF-1 defibrillation lead, but smaller than the lead connector pin of an IS-1 pacemaker lead. While providing for effective lockout operation, the overall dimensions of the remainder of the lead connector of a preferred embodiment of the present invention remain generally consistent with the IS-1 standards to permit the non-cardiac connector port and connectors to be manufactured with minimal changes to existing header and lead designs.  
         [0014]     As a result of the design of the connector arrangement of the present invention, the non-cardiac lead cannot be mechanically or electrically connected to a DF-1 defibrillation port, thus effectively barring the potential harm that could be done if a high-energy defibrillation pulse were delivered to a non-cardiac lead. Conversely, a DF-1 defibrillation lead cannot be inadvertently electrically connected to a non-cardiac port on the implantable pulse generator. While an IS-1 pacemaker lead could be mechanically inserted into the non-cardiac lead port of a header for an implantable pulse generator in accordance with the present invention, the electrical contact arrangement within the non-cardiac lead port prevents any inadvertent electrical connection from being effectively made. Conversely, the non-cardiac stimulation lead pin cannot make effective electrical connection with an IS-1 pacemaker lead port. Thus, the potential harm caused by a tissue stimulation therapy pulse being delivered to cardiac tissue through a pacing lead that uses an IS-1 standard, or a pacing stimulation therapy pulse being delivered to a non-cardiac lead, is effectively obviated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a perspective view of a medical electrical implantable pulse generator and associated electrical leads.  
         [0016]      FIG. 2  is a cross-sectional view of the IS-1 pacemaker lead connector that meets the ISO 5841-3 standard.  
         [0017]      FIG. 3  is a cross-sectional view of the IS-1 pacemaker lead connector port that meets the ISO 5841 standard.  
         [0018]      FIG. 4  is a cross-sectional view of the DF-1 defibrillator lead connector that meets the ISO 11318:2002 standard.  
         [0019]      FIG. 5  is a cross-sectional view of the DF-1 defibrillator lead connector port that meets the ISO 11318:2002 standard.  
         [0020]      FIG. 6  is a cross-sectional view of the non-cardiac lead connector in accordance with the present invention.  
         [0021]      FIG. 7  is a cross-sectional view of the non-cardiac lead connector port in accordance with the present invention that interfaces with the non-cardiac lead connector as shown in  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     An implantable pulse generator device typically includes an electrical medical device such as a pacemaker, cardioverter, defibrillator, baroreflex activation device, nerve stimulator, muscle stimulator, implantable monitor or other medical device and one or more electrical leads. Typically, the pulse generator device comprises a case and a header attached to the case. The case typically contains the electronics and the power source (usually a battery) for the implantable pulse generator. The leads are connected to the implantable pulse generator through ports in the header.  
         [0023]     Referring to  FIG. 1 , there is shown an implantable pulse generator device  10  that is comprised of a header  20  and a case  22  containing a power source  24  and electronics  26 . The header portion  20  of the implantable pulse generator device  10  is typically formed of a molded thermoplastic material, such as an acrylic material, and includes a plurality of ports  50  (pacing),  70  (defibrillation), and  90  (non-cardiac). While the number of ports shown in this embodiment is three, a greater or lesser number of ports is contemplated by the scope of the present invention. Each port  50 ,  70 ,  90  includes a corresponding orifice  51 ,  71 ,  91 , which is the entry point to the port  50 ,  70 ,  90  and the interior of the header  20 . Electrical leads  30 ,  32  connect the implantable pulse generator device  10  to electrodes  34 ,  36  typically located at their distal end that are positioned proximate a particular location in the body to be stimulated or sensed. The electrical leads  30 ,  32  are connected to the header  20  through the appropriate orifice  51 ,  71 ,  91  of the corresponding port  50 ,  70 ,  90  by way of a lead connector  40 ,  60  or  80 . As will be described, a given lead connector  40 ,  60 ,  80  is designed to be inserted into a corresponding one of the ports  50 ,  70 ,  90  and mechanically and electrically couples the associated lead  30 ,  32  with the header  20 .  
         [0024]     The electrical leads may be cardiac leads  30  designed in accordance with either the IS-1 or DF-1 standard, or other types of cardiac leads  30 , such as the left ventricular lead described in U.S. Pat. No. 6,044,302, or may be non-cardiac leads  32  that are intended for stimulation and/or sensing of tissue or organs other than the heart. In a preferred embodiment of the present invention, the non-cardiac lead connector and lead connector port are adapted for a non-cardiac lead  32  that includes a non-cardiac stimulation electrode  36 . One such example of a non-cardiac stimulation electrode is a baroreflex activation lead and electrode for baroreflex activation, such as shown in U.S. Pat. No. 6,522,926 and U.S. Publ. Appl. Nos. 2003/0060857A1 and 2004/0010303A1, the disclosures of which are hereby incorporated by reference. Alternatively, the non-cardiac lead connector and lead connector port of the present invention may be utilized for any non-cardiac stimulation application, such as nerve, muscle or other tissue or organ stimulation.  
         [0025]      FIG. 2  is a cross-sectional view of the pacemaker lead connector  40  that meets the ISO 5841-3 standard. The lead connector  40  for the cardiac lead  30  comprises a lead connector body  42  and a lead connector pin  44 . The lead connector pin  44  is located at the proximal end of the lead connector  40  and, when locked in place in the port  50 , forms a mechanical and physical connection between the lead connector  40  and the header  20 . The lead connector pin  44  is made of conductive material.  
         [0026]     The lead connector body  42  has a number of different diameters, as the lead connector body  42  tapers towards the lead connector pin  44 . The diameter  40   d   l , of the lead connector body  42  proximate the lead is 3.1+/−0.3 millimeters. The diameter of the main section of the lead connector body  42 ,  40   d   2 , is 3.23+/−0.1 millimeters. This section of the lead connector body  42  extends up to the first shoulder  46 , where at least one sealing ring  47  is located. At the first shoulder  46 , the lead connector body  42  tapers to a diameter  40   d   3  of 2.66+/−0.03 millimeters to 2.66+/−0.05 millimeters. A second sealing area with at least one sealing ring  48  precedes the second shoulder  49  of the lead connector body  42 . At the second shoulder  49 , the lead connector body  42  tapers again such that the lead connector pin  44  is formed with a diameter  40   d   4  of 1.59+/−0.03 millimeters. The lead connector pin  44  forms the electrical connection between the lead and the header  20 .  
         [0027]     The connector port or cavity  50  that is designed to fit with the pacemaker lead connector  40  is shown in  FIG. 3 . In one embodiment, the pacemaker lead connector port  50  also meets the requirement of ISO 5841-3 and is referred to as an IS-1 port. The lead connector port  50  has an orifice  25  that provides access for the lead connector  40  into the lead connector port  50 . The lead connector port has a main body  52  with a diameter  50   d   1  of 3.15+/−0.15 millimeters that, at the sealing ring zone  57  is  50   d   2  3.48+/−0.05 millimeters. Just past the sealing ring zone  57  the first shoulder  56  of the lead connector port  50  is formed. The lead connector port  50  tapers at the first shoulder  56  and at the second sealing zone  58 , the diameter  50   d   3  is 2.75+/−0.03 millimeters. Following the second sealing zone  58 , a second shoulder  59  is formed in the lead connector port  50 , proximate the lead connector pin port  54 . The lead connector port  50  tapers again to form the lead connector pin port  54  that has a minimum diameter  50   d   4  of 1.65 millimeters. Hence, the lead connector pin  44  of the pacemaker lead connector  40  fits through the lead connector pin port  54 , allowing for the lead connector pin  44  to form a mechanical and electrical connection with the header  20 .  
         [0028]      FIG. 4  is a cross-sectional view of the defibrillator lead connector  60  that meets the ISO 11318:2002 standard. The lead connector  60  for the cardiac lead  30  comprises a lead connector body  62  and a lead connector pin  64 . The lead connector pin  64  is located at the proximal end of the lead connector  60  and, when locked in place in the port  70 , forms a mechanical and physical connection between the lead connector  60  and the header  20 . The lead connector pin  64  is made of conductive material.  
         [0029]     The lead connector body  62  has a number of different diameters, as the lead connector body  62  tapers towards the lead connector pin  64 . The diameter  60   d   1  of the lead connector body  62  proximate the lead is 3.23+/−0.1 millimeters. The diameter of the main section of the lead connector body  62 ,  60   d   2  is 3.23 +0.1, −0.2 millimeters. This section of the lead connector body  62  extends up to the first shoulder  66 , where at least one sealing ring  67  is located. At the first shoulder  66 , the lead connector body  62  tapers slightly and then expands to accommodate the at least one sealing ring to a diameter  60   d   3  of 3.36+/−0.01 millimeters. A second sealing area with at least one sealing ring  68  precedes the second shoulder  69  of the lead connector body  62 . At the second shoulder  69 , the lead connector body  62  tapers again such that the lead connector pin  64  is formed with a diameter  60   d   4  of 1.25+/−0.03 millimeters. The lead connector pin  64  forms the electrical connection between the lead and the header  20 .  
         [0030]     The connector port or cavity  70  that is designed to fit with the defibrillator lead connector  60  is shown in  FIG. 5 . In one embodiment, the defibrillator lead connector port  70  also meets the requirement of ISO 11318:2002(E) and is referred to as a DF-1 port. The lead connector port  70  has an orifice  25  that provides access for the lead connector  60  into the lead connector port  70 . The lead connector port  70  has a main body  72  with a minimum diameter  70   d   1  of 3.43+/−0.15 millimeters that, at the sealing ring zone  77  is  70   d   2  3.48+/−0.05 millimeters. Just past the sealing ring zone  77  the first shoulder  76  of the lead connector port  70  is formed. The lead connector port  70  tapers at the first shoulder  76 . However, just prior to the first shoulder  76 , and at the second sealing zone  78 , the diameter  70   d   3  is 3.5+/−0.25 millimeters. Following the second sealing zone  78 , the first shoulder  76  is formed in the lead connector port  70 , proximate the lead connector pin port  74 . The lead connector port  70  tapers to form the lead connector pin port  74  that has a diameter  70   d   4  of 1.31 millimeters. Hence, the lead connector pin  64  of the defibrillator lead connector  60  fits through the lead connector pin port  74 , allowing for the lead connector pin  64  to form a mechanical and electrical connection with the header  20 .  
         [0031]      FIG. 6  is a cross-sectional view of a preferred embodiment of a non-cardiac lead connector  80  for a non-cardiac lead  32 . The non-cardiac lead connector  80  comprises a lead connector body  82  and a lead connector pin  84 . The lead connector pin  84  is located at the proximal end of the lead connector  80  and, when locked in place in the non-cardiac lead port  90 , forms a mechanical and physical connection between the non-cardiac lead connector  80  and the header  20 . The lead connector pin  84  is made of conductive material.  
         [0032]     The lead connector body  82  has a number of different diameters, as the lead connector body  82  tapers towards the lead connector pin  84 . The diameter  80   d   1  of the lead connector body  82  proximate the lead is 3.1+/−0.3 millimeters. The diameter of the main section of the lead connector body  82 ,  80   d   2  is 3.23+/−0.1 millimeters. This section of the lead connector body  82  extends up to the first shoulder  86 , where at least one sealing ring  87  is located. At the first shoulder  86 , the lead connector body  82  tapers to a diameter  80   d   3  of 2.66+/−0.03 millimeters to 2.66+/−0.05 millimeters. A second sealing area with at least one sealing ring  88  precedes the second shoulder  89  of the lead connector body  82 . At the second shoulder  89 , the lead connector body  82  tapers again such that the lead connector pin  84  is formed with a diameter  80   d   4  of 1.410+/−0.013 millimeters. The lead connector pin  84  forms the electrical connection between the lead and the header  20 . As will be seen from a comparison of the lead connector body  82  of the non-cardiac lead  32  with the lead connector body  42  of the pacemaker IS-1 lead  30 , all of the other dimensions up to the lead connector pin  84  are generally consistent with the dimensions of the IS-1 lead connector body  42 .  
         [0033]     The non-cardiac lead connector port or cavity  90  that is designed to fit with the non-cardiac lead connector  80  is shown in  FIG. 7 . The non-cardiac lead connector port  90  has an orifice  91  that provides access for the lead connector  80  into the lead connector port  90 . The lead connector port  90  has a main body  92  with a diameter  90   d   1  of 3.15+/−0.15 millimeters that, at the sealing ring zone  97  is  90   d   2  3.48+/−0.05 millimeters. Just past the sealing ring zone  97  the first shoulder  96  of the lead connector port  90  is formed. The lead connector port  90  tapers at the first shoulder  96  and at the second sealing zone  98 , where the diameter  90   d   3  is 2.75+/−0.03 millimeters. Following the second sealing zone  98 , a second shoulder  99  is formed in the lead connector port  90 , proximate the lead connector pin port  94 . The lead connector port  90  tapers again to form the lead connector pin port  94  that has a diameter  90   d   4  of 1.50+/−0.02 millimeters. Hence, the lead connector pin  84  of the non-cardiac lead connector  80  fits through the lead connector pin port  94 , allowing for the lead connector pin  94  to form a mechanical and electrical connection with the header  20 .  
         [0034]     The non-cardiac lead connector pin  84  has been designed to have a diameter that is intermediate the defibrillator (DF-1) lead connector pin diameter and the pacemaker (IS-1) lead connector pin diameter. The ranges of diameters for lead connector pins and lead connector pin ports for the defibrillation lead (DF-1), the pacemaker lead (IS-1) and a preferred embodiment of a non-cardiac lead are provided in Table 1.  
                                         TABLE 1                                   LEAD   LEAD CONNECTOR           CONNECTOR PIN   PIN PORT           DIAMETER (mm)   DIAMETER (mm)                                    DEFIBRILLATOR   1.25 ± 0.03   1.31       DF-1       PACEMAKER IS-1   1.59 ± 0.03   1.65 minimum       NON-CARDIAC (e.g.,   1.410 ± 0.013   1.50 ± 0.02       BAROREFLEX       ACTIVATION DEVICE)                  
 
         [0035]     An advantage derived from the design of the non-cardiac lead connector  80  and corresponding port  90  is that an effective lockout connector arrangement is provided between the non-cardiac lead  32  and any standardized cardiac leads  30  for the implantable medical devices noted above. Due to the size of the diameter of the non-cardiac lead connector pin  84 , the non-cardiac lead  32  cannot be mated with the defibrillator lead connector pin port  70 . Since this connection is prevented, the possibility of high-energy defibrillation pulses inducing localized tissue damage, or worse trauma, is effectively eliminated. Another advantage derived from the configuration of the non-cardiac lead connector  80  and the corresponding port  90  is that the pacemaker lead connector (IS-1) pin  44  cannot be operably coupled with the non-cardiac lead connector pin port  94 . Hence, the possibility of baroreflex activation therapies, for example, causing harm because they were delivered to cardiac tissue through a pacing lead (IS-1) also has been effectively eliminated as a result of the design in accordance with the present invention.  
         [0036]     While the present invention has been described with respect to particular standards for the cardiac leads  30  and to one embodiment of a non-cardiac lead  32  for baroreflex activation proximate the carotid sinus, it is to be understood that variations in the present invention can be made without departing from the novel aspects of this invention as defined in the claims. For example, it is not necessary for an implantable pulse generator to have one or both of connector ports  50  (pacing) and  70  (defibrillation), such as in the case where the implantable pulse generator is solely designed for non-cardiac stimulation/sensing purposes. Alternatively, an implantable pulse generator which combined one or both of pacing and defibrillation therapies with a non-cardiac therapy, such as nerve stimulation, would have one or both of the connector ports ( 50 ) and  70  (defibrillation) in conjunction with the non-cardiac port  90  in accordance with the present invention.