Endocardial stimulation/defibrillation system of the left ventricle

Abstract

A system for the endocardial stimulation/defibrillation of the left ventricle. This system includes a generator ( 60 ) and an endocardial lead having a distal end ( 30 ) which extends into the right ventricle ( 14 ). The lead includes anchor ( 32 ) for coupling the distal end to the interventricular septum ( 20 ). The lead body carries on it a stimulating and/or defibrillation electrode ( 38 ) ( 64, 66 ). A microcable ( 42 ) extends into the lead body and beyond, with an intermediate portion ( 56 ) crossing from one side of the interventricular septum ( 20 ) to the other, and an active free portion ( 58 ) that emerges in the left ventricle ( 16 ). The microcable is coupled to the generator, to produce an electric field ( 62 ) between, on one hand, the stimulation electrode ( 38 ) or defibrillation electrode ( 64, 66 ) of the lead body and, on the other hand, a bare region of the active free portion ( 58 ) of microcable ( 42 ).

1 . A system for the endocardial stimulation/defibrillation of the left ventricle comprises:
 a generator;   an endocardial lead comprising a body having a distal end which extends into the right ventricle, wherein the endocardial lead further comprises an anchor which anchors the distal end to the interventricular septum, and wherein the lead body comprises an electrode;   a microcable extending from the distal end of the lead body through the interventricular septum and emerging in the left ventricle, wherein the microcable is electrically coupled to the generator such that the generator produces an electric field between the electrode and an active portion of the microcable within the left ventricle.   
     
     
         2 . The system of  claim 1 , wherein the microcable comprises an intermediate portion which extends through the interventricular septum. 
     
     
         3 . The system of  claim 2 , wherein the microcable comprises an insulating sheath which covers an electrical conductor in the intermediate portion and wherein the active portion comprises a portion wherein a conductor is exposed and not covered by the insulating sheath. 
     
     
         4 . The system of  claim 3 , wherein the body comprises a deformable material having an inner lumen through which the microcable extends. 
     
     
         5 . The system of  claim 4 , wherein the microcable is slidable through the inner lumen of the body. 
     
     
         6 . The system of  claim 5 , wherein the electrical conductor comprises a core in the active portion of between about 0.2 and 0.4 mm. 
     
     
         7 . The system of  claim 6 , wherein the microcable comprises a strand formed of a plurality of strands with at least one composite strand comprising a first material having properties of mechanical resistance to bending fatigue superior to those of other materials of the strand. 
     
     
         8 . The system of  claim 7 , wherein the composite strand comprises a second material that is radio-opaque. 
     
     
         9 . The system of  claim 8 , wherein the composite strand further comprises: a third material having properties of electrical conductivity greater than those of the other materials of the strand. 
     
     
         10 . The system of  claim 9 , wherein the microcable is formed of a plurality of composite strands, with a core wire comprising said second material, this core wire being surrounded by composite wires each including said first material as a surface material. 
     
     
         11 . The system of  claim 1 , wherein the anchor comprises an extending helical screw for penetration into the interventricular septum wall under the effect of a screw motion imparted to the lead body from the proximal end thereof. 
     
     
         12 . The system of  claim 1 , wherein the length of the active portion is between about 30 and 120 mm. 
     
     
         13 . The system of  claim 1  wherein the length of the active free portion is between about 45 and 55 mm. 
     
     
         14 . The system of  claim 1 , wherein the length of the intermediate portion is between about 10 and 20 mm. 
     
     
         15 . An endocardial lead comprising:
 an elongated lead body having an internal lumen and a distal end;   a screw anchor projecting front a distal end of the elongated body; and   a microcable separate from the screw anchor and slidably engaged with the lead body through a lumen extending through the lead body, wherein the lead does not include a guide catheter.   
     
     
         16 . The lead of  claim 15 , wherein the microcable does not exceed 0.7 mm. 
     
     
         17 . A method for endocardial stimulation/defibrillation of the left ventricle, comprising:
 inserting an elongated lead body into the right ventricle;   securing a distal end of the elongated lead body to the interventricular septum using an anchor extending from the elongated lead body;   sliding a microcable through an internal lumen in the elongated body and through the interventricular septum such that a free end of the microcable extends within the left ventricle, wherein the portion of the microcable which moves through the interventricular septum is between about 0.5 and 0.7 mm in diameter.   
     
     
         18 . The method of  claim 17 , wherein the microcable is extended through the interventricular septum without the use of a guide catheter. 
     
     
         19 . The method of  claim 18 , further comprising:
 using a radiofrequency puncture generator coupled to the microcable to generate radiofrequency energy to puncture the interventricular septum.   
     
     
         20 . The method of  claim 19 , wherein the microcable comprises a conductive core covered by an insulating sheath and wherein the microcable comprises at least one strand of material resistant to flexing.