Abstract:
An epicardial pacing lead comprising a flexible, elongated lead body having a proximal end and a distal end; an electrode coupled to the lead body near the distal end; a housing coupled to the lead body proximal to the electrode; and a platform at least partially encompassed by the housing, the platform including at least four tines, each tine adapted for engagement with the epicardium and including an upper section extending outwardly from the platform and a lower section extending distally at an angle to the upper section.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to cardiac leads used in combination with a cardiac function management device such as a heart pacemaker or defibrillator to monitor and control the rhythm of the heart. The present invention more particularly relates to fasteners used to attach the cardiac lead to the epicardial heart surface.  
       BACKGROUND  
       [0002]     Cardiac function management systems are used to treat heart arrhythmias. Pacemaker systems are commonly implanted in patients to treat bradycardia (i.e., abnormally slow heart rate). A pacemaker system includes an implantable pulse generator and leads, which form the electrical connection between the implantable pulse generator and the heart. An implantable cardioverter defibrillator (“ICD”) is used to treat tachycardia (i.e., abnormally rapid heart rate). An ICD also includes a pulse generator and leads that deliver electrical energy to the heart.  
         [0003]     The leads coupling the pulse generators to the cardiac muscle are commonly used for delivering an electrical pulse to the cardiac muscle, for sensing electrical signals produced in the cardiac muscle, or for both delivering and sensing. The leads are susceptible to categorization according to the type of connection they form with the heart. An endocardial lead includes at least one electrode at or near its distal tip adapted to contact the endocardium (i.e., the tissue lining the inside of the heart). An epicardial lead includes at least one electrode at or near its distal tip adapted to contact the epicardium (i.e., the tissue lining the outside of the heart). Finally, a myocardial lead includes at least one electrode at or near its distal tip inserted into the heart muscle or myocardium (i.e., the muscle sandwiched between the endocardium and epicardium).  
         [0004]     The lead typically consists of a flexible conductor surrounded by an insulating tube or sheath that extends from the electrode at the distal end to a connector pin at the proximal end. The lead electrode at the distal end is attached to the heart tissue using a fastening device. Fastening devices currently known in the art include a helix, which is screwed into the epicardial tissue. There is a need for an electrode fastening device that provides for quick and secure placement and enhances attachment success.  
       SUMMARY  
       [0005]     An epicardial pacing lead comprising a flexible, elongated lead body having a proximal end and a distal end; an electrode coupled to the lead body near the distal end; a housing coupled to the lead body proximal to the electrode; and a platform at least partially encompassed by the housing, the platform including at least four tines, each tine adapted for engagement with the epicardium and including an upper section extending outwardly from the platform and a lower section extending distally at an angle to the upper section.  
         [0006]     A method of using an epicardial pacing lead comprising providing an epicardial pacing lead comprising a flexible, elongated lead body having a proximal end and a distal end, an electrode coupled to the lead body near the distal end, a housing coupled to the lead body proximal to the electrode, and a platform at least partially encompassed by the housing, the platform including at least four tines, each tine including an upper section extending outwardly from the platform and a lower section extending distally at an angle to the upper section; inserting the platform into an attachment device having a support section and a bending section slideably engaged with the support section so that the support section holds the platform; positioning the platform adjacent to the epicardium so that the tines are positioned to pierce the epicardium; and actuating the bending section so that the bending section slides past the support section and forces the lower section of the tines into the epicardium, thereby attaching the platform to the epicardium.  
         [0007]     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. As will be realized, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  shows a perspective view of an implantable cardiac function management system according to the present invention.  
         [0009]      FIG. 2A  shows a side plan view of a fastening device according to one embodiment of the present invention.  
         [0010]      FIG. 2B  shows a top plan view of the fastening device of  FIG. 2A .  
         [0011]      FIG. 3A  shows a bottom plan view of the fastening device of  FIG. 2A  positioned in an attachment device prior to attachment.  
         [0012]      FIG. 3B  shows a side plan view of the fastening device of  FIG. 2A  after the fastening device has been attached to the epicardial tissue.  
         [0013]      FIG. 4A  shows a side plan view of another embodiment of the present invention.  
         [0014]      FIG. 4B  shows a top plan view of the fastening device of  FIG. 4A .  
         [0015]      FIG. 5A  shows a bottom plan view of the fastening device of  FIG. 4A  positioned for attachment in the attachment device prior to attachment.  
         [0016]      FIG. 5B  shows a side plan view of the fastening device of  FIG. 4A  after the fastening device has been attached to the epicardial tissue.  
         [0017]      FIG. 6A  shows a top plan view of another embodiment of the present invention.  
         [0018]      FIG. 6B  shows a side plan view of the fastening device of  FIG. 6A .  
         [0019]      FIG. 7A  shows a bottom plan view of the fastening device of  FIG. 6A  positioned for attachment in the attachment device prior to attachment.  
         [0020]      FIG. 7B  shows a side plan view of the fastening device of  FIG. 6A  after the fastening device has been attached to the epicardial tissue.  
         [0021]      FIG. 8  shows a flowchart describing a method of using an epicardial lead.  
         [0022]      FIG. 9A  shows a top plan view of the fastening device of  FIG. 2A  positioned for removal in a removal device.  
         [0023]      FIG. 9B  shows a side plan view of the fastening device of  FIG. 2A  after removal. 
     
    
       [0024]     While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.  
       DETAILED DESCRIPTION  
       [0025]      FIG. 1  is a perspective view of a cardiac function management system  10 . The system  10  includes a pulse generator  12  and a cardiac lead  14 . The lead  14  operates to convey electrical signals between the heart  16  and the pulse generator  12 . A proximal end  18  of the lead  14  is coupled to the pulse generator  12  and a distal end  20  is coupled to the heart  16 . The lead  14  includes a lead body  22  extending from the lead proximal end  18  to the lead distal end  20 .  
         [0026]     As shown in  FIG. 1 , an electrode  24  is attached to the epicardium  26  of heart  16  by the fastening device  28 . When positioned as above, the electrode  24  can be used to sense the electrical activity of the heart  16  or to apply a stimulating pulse to the left ventricle  30 . In other embodiments, the cardiac lead  14  of the present invention can also be implanted in any other portion of the heart as known in the art of cardiac function management. For example, it may be implanted in the right atrium  32  or the right ventricle  34 .  
         [0027]      FIG. 2A  is a side plan view of one embodiment of the fastening device  28 . In this embodiment, the fastening device  28  includes a housing  36  and a platform  38  which is partially encompassed by the housing  36 . The housing  36  can be integral with the lead insulation  40 . The platform  38  includes tines  42 . The tines  42  include upper sections  44  and lower sections  46 . The upper sections  44  extend outwardly from the platform  38 . As shown in  FIG. 2A , the upper sections  44  are substantially parallel with the platform  38  and the lower sections  46  are bent at an angle of approximately 90 degrees to the upper sections  44 . The lower sections  46  include proximal ends  48  and distal ends  50 . Points  52  for piercing the epicardium can be located at the distal ends  50 .  
         [0028]     Alternatively, the upper sections  44  need not be substantially parallel to the platform  38 , but instead may be bent at some other angle to the platform  38 . The lower sections  46  may also be bent at some angle other than 90 degrees to the upper sections  44 . In one embodiment, the angle between the upper sections  44  and the lower sections  46  can range from approximately 70 to approximately 120 degrees. The platform  38  and tines  42  can be made out of any malleable metal, such as stainless steel. The tines may be straight, as is shown in  FIG. 2A , or may be curved.  
         [0029]      FIG. 2B  is a top plan view of the fastening device  28  of  FIG. 2A . The housing  36  includes an aperture  54  through which the lead body  22  passes. There is a corresponding aperture  56  in the platform  38 . As shown in  FIG. 2A , the platform  38  has a substantially rectangular shape and also the housing  36  has a substantially rectangular shape. Alternatively, the housing  36  could have any other shape suitable for partially encompassing the platform  38 . The housing  36  can be made out of silicone or polyurethane. The housing  36  can be made out of any other material suitable for retaining the lead body  22 . Four tines  42  are shown in  FIGS. 2A and 2B , but the number of tines  42  may vary as needed. In one embodiment, the penetration of the electrode  24  into the epicardium  26  can range from approximately 0 to 10 millimeters. In one embodiment, the ratio of the length of the platform  38  to the diameter of the lead body  22  can vary between about 2:1 and about 4:1.  
         [0030]      FIG. 3A  is a bottom plan view of the fastening device  28  of  FIG. 2A  after the fastening device  28  has been slideably inserted in an attachment device  58 . One such attachment device is disclosed in U.S. Pat. No. 5,829,662 to Allen, et al., which is hereby incorporated by reference. As shown, the attachment device  58  includes a support section  60  and bending sections  62 . The fastening device  28  is interposed between the support section  60  and the bending sections  62 . The bending sections  62  overlay the tines  42 . During deployment, the platform  38  of the fastening device  28  is positioned so tines  42  can pierce the epicardium  26 . The support section  60  includes an opening  64  adapted to fit around the lead body  22 .  
         [0031]      FIG. 3B  shows a side plan view of the fastening device of  FIG. 2A  in a deformed or deployed configuration. When a force is applied to the attachment device  58  so that the bending sections  62  slide past the support section  60  toward the epicardium  26 , the upper sections  44  of tines  42  are bent, creating a bend  66 . As shown in  FIG. 3B , this bending forces the points  52  of lower sections  46  through the epicardium  26  and into the myocardium  68 , thereby attaching the fastening device  28  and the electrode  24  to the heart  16 . After attachment, the support section  60  of the attachment device  58  can then be slid in direction y (as shown in  FIG. 3A ) and the fastening device  28  is thereby released from the attachment device  58 .  
         [0032]      FIG. 4A  shows an alternative embodiment of the present invention. In this embodiment, the housing  36  partially encompasses two platforms  38 . Each platform  38  includes tines  42 . The tines  42  include upper sections  44  and lower sections  46 . The upper sections  44  extend outwardly from the platforms  38 . The lower sections  46  include proximal ends  48  and distal ends  50 . The distal ends  50  can include points  52  for piercing the epicardium. As shown in  FIG. 4B , the housing  36  includes an aperture  54  through which the lead body  22  passes. Although four tines  42  are shown in  FIGS. 4A and 4B , the number of tines  42  may vary. The angle between the upper sections  44  and the lower sections  46 , as well as the angle between the upper sections  44  and the platforms  38  may also vary. In one embodiment, the angle between the upper sections  44  and the lower sections  46  can range from approximately 70 to approximately 120 degrees. In one embodiment, the penetration of the electrode  24  into the epicardium  26  can range from approximately 0 to 10 millimeters. In one embodiment, the ratio of the length of the platforms  38  to the diameter of the lead body  22  can vary between about 2:1 and about 4:1.  
         [0033]      FIG. 5A  is a bottom plan view of the fastening device  28  of  FIG. 4A  after the fastening device  28  has been slideably inserted in the attachment device  58 . The attachment device  58  includes a support section  60  and a bending sections  62 . The fastening device  28  is interposed between the support section  60  and the bending sections  62 . During deployment, the support section  60  is located adjacent to the epicardium  26 . The support section  60  includes an opening  64  adapted to fit around the lead body  22 .  
         [0034]      FIG. 5B  shows a side plan view of the fastening device of  FIG. 4A  in a deformed or deployed configuration. When a force is applied to the attachment device  58  so that bending sections  62  slide past the support section  60  toward the epicardium  26 , the upper sections  44  of tines  42  are bent, creating a bend  66 . As shown in  FIG. 5B , this bending forces the points  52  of lower sections  46  through the epicardium  26  and into the myocardium  68 , thereby securing the fastening device  28  and the electrode  24  to the heart  16 . After attachment, the support section  60  of the attachment device  58  can then be slid in direction Y as shown in  FIG. 5A , and the fastening device  28  is thereby released from the attachment device  58 .  
         [0035]      FIGS. 6A-6B  show yet another alternative embodiment of the present invention. In this embodiment, the platform  38  has a substantially annular shape and includes an aperture  56 . The housing  36  encompassing the platform  38  is also substantially annular and includes an aperture  54 . The lead body  22  passes through the apertures  54  and  56 . Tines  42  extend from the platform  38 . The tines  42  have an upper section  44  and a lower section  46 . The lower sections  46  have proximal ends  48  and distal ends  50 . The points  52  for piercing the epicardium  26  can be located at the distal ends  50 .  
         [0036]     Although four tines  42  are shown in  FIGS. 6A and 6B , the number of tines  42  may vary. In one embodiment, the tines  42  are spaced at approximately 90 degrees from each other. The angle between the upper sections  44  and the lower sections  46 , as well as the angle between the upper sections  44  and the platforms  38  may also vary. In one embodiment, the angle between the upper sections  44  and the lower sections  46  can range from approximately 70 to approximately 120 degrees. In one embodiment, the penetration of the electrode  24  into the epicardium  26  can range from approximately 0 to 10 millimeters. In one embodiment, the ratio of the diameter of the platform  38  to the diameter of the lead body  22  can vary between about 2:1 and about 4:1.  
         [0037]      FIG. 7A  shows the fastening device of  FIGS. 6A and 6B  after it has been positioned in the attachment device  58 . The attachment device includes support sections  60  and bending sections  62 . The fastening device  28  is interposed between the support sections  60  and the bending sections  62 . The bending sections  62  overlay the tines  42 . During deployment, the support sections  60  are located adjacent to the epicardium  26  and retain the fastening device  28  by clamping onto the fastening device  28 .  
         [0038]      FIG. 7B  shows a side plan view of the fastening device of  FIG. 6A  in a deformed or deployed configuration. When a force is applied to the attachment device  58  so that the bending sections  62  slide past the support sections  60  toward the epicardium  26 , a bend  66  is created in the upper sections  44  of tines  42 . As shown in  FIG. 7B , this bending forces the points  52  of lower sections  46  through epicardium  26  and into the myocardium  68 , thereby securing the fastening device  28  and the electrode  24  to the heart  16 . After attachment, the support sections  60  of the attachment device  58  move in direction z shown in  FIG. 7A , thus releasing the fastening device  28 .  
         [0039]      FIG. 8  depicts an exemplary implantation process  100  for attaching the cardiac lead  14  to the heart  16 . The cardiac lead may be implanted using any technique known in the art. Exemplary techniques include a thoracotomy/thorascopic approach and an endoscopic subxiphoid surgical procedure, such as is disclosed in U.S. Patent Publication 2004/0111101 A1 to Chin, which is hereby incorporated by reference. As shown, a cardiac lead  14  and a fastening device  28  having a platform  38  and housing  36  are provided (block  110 ). The platform  38  is inserted into an attachment device  58  having a support section  60  and bending sections  62  (block  120 ). The fastening device  28  may be slideably inserted into the attachment device  58  (see  FIGS. 3A and 5A ) or it may be clamped by the attachment device  58  (see  FIG. 7A ). The platform  38  is then located adjacent to the epicardium  26  so that the tines  42  are positioned to pierce the epicardium  26  (block  130 ). The attachment device  58  is actuated, causing the bending section  62  to slide past the support section  60 , thus bending lower sections  46  of tines  42  and thereby attaching the fastening device  28  to the heart  16  (block  140 ).  
         [0040]      FIG. 9A  shows a top plan view of the fastening device  28  of  FIG. 2A  positioned for removal in a removal device  70 . As shown in  FIG. 9A , the removal device  70  includes a support section  72  and bending sections  74 . The fastening device  28  is interposed between the support section  72  and the bending sections  74 . During removal, the bending sections  74  are positioned adjacent to the epicardium  26 . The support section  72  includes an opening  76  adapted to fit around the lead body  22 . When the removal device  70  is actuated, the bending sections  74  slide past the support section  72  and away from the epicardium  26 .  
         [0041]      FIG. 9B  shows a side plan view of the fastening device of  FIG. 2A  after removal. As bending sections  74  slide past the support section  72 , a bend  78  is created in the fastening device  28  and the tines  42  are pulled out of the heart  16 . As shown, the removal device  70  is adapted to pull four tines  42  out of the epicardium  26 , but the removal device  70  can pull as many tines  42  as is necessary.  
         [0042]     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.