Medical electrical lead having bending stiffness which increase in the distal direction

An elongated implantable medical electrical lead for electrically *stimulating a human heart or sensing electrical signals originating therefrom, comprising:

• (a) a lead body having proximal and distal sections;
• (b) at least one electrode for sensing or electrically stimulating the heart;
• (c) a proximal end comprising an electrical connector, the electrical connector being contiguous with the proximal section of the lead body;
• (d) a distal end contiguous with the distal section of the lead body;
• (e) at least one electrical conductor having proximal and distal ends, the distal end of the conductor being operatively connected to the at least one electrode, the proximal end of the conductor being operatively connected to the electrical connector;
• wherein the distal section of the lead body comprises at least first and second segments, the first segment having a bending stiffess Sbs which exceeds the bending stiffness Sbf of the second segment, the first and second segments being configured and dimensioned to impart a distally directed force to the distal end of the lead when the first and second segments are subjected to a bending moment resulting in a sufficient curvature of the distal section of the lead body, the first segment being located distally in respect of the second segment, the distal section of the lead body having an outer diameter ranging between about 0.5 mm and about 3 mm, the lead being adapted, sized and configured for placement in one or more of a coronary vein, a coronary sinus and a right atrial appendage, and,
• wherein the lead, the at least one electrode, and the first and second segments are configured and dimensioned to form a single pass lead for dual chamber pacing of a left atrium and a left ventricle via implantation within a coronary sinus and a great cardiac vein of the heart.

A method of electrically stimulating a patient's heart with an implantable cardiac stimulator and an elongated implantable medical electrical lead, the lead comprising a lead body having proximal and distal sections, at least one electrode for sensing or electrically stimulating the heart, a proximal end comprising an electrical connector, the electrical connector being contiguous with the proximal section of the lead body, the electrical connector being configured for operative attachment to the cardiac stimulator, a distal end contiguous with the distal section of the lead body, at least one electrical conductor having proximal and distal ends, the distal end of the conductor being operatively connected to the at least one electrode, the proximal end of the conductor being operatively connected to the electrical connector, the distal section of the lead body comprising at least first and second segments, the first segment having a bending stiffness Sbs which exceeds the bending stiffness Sbf of the second segment, the first and second segments being configured and dimensioned to impart a distally directed force to the distal end of the lead when the first and second segments are subjected to a bending moment resulting in a sufficient curvature of the distal section of the lead body, the first segment being located distally in respect of the second segment, the distal section of the lead body having an outer diameter ranging between about 0.5 mm and about 3 mm, the lead being adapted, sized and configured for placement in one or, more of a coronary vein, a coronary sinus and a right atrial appendage, the method comprising:

• (a) providing the cardiac stimulator;
• (b) providing the medical electrical lead;
• (c) transvenously inserting and positioning the lead through a coronary sinus and into a coronary vein in the heart,
• (d) operatively connecting the connector of the lead to the cardiac stimulator;
• and
• (e) delivering at least one electrical pulse originating in the cardiac stimulator through the lead and the at least one electrode to the heart.

A method of electrically stimulating a patient's heart with an implantable cardiac stimulator and an elongated implantable medical electrical lead, the lead comprising an elongated lead body comprising proximal and distal sections, the elongated lead body defining axial distances which increase distally, at least one electrode for sensing or electrically stimulating the heart, a proximal end comprising an electrical connector, the connector being contiguous with the proximal section of the lead body, a distal end portion contiguous with the distal section of the lead body, the distal end portion extending distally from the distal section of the lead body, at least one electrical conductor having proximal and distal ends, the distal end of the conductor being operatively connected to the at least one electrode, the proximal end of the conductor being operatively connected to the electrical connector, the distal section of the lead body further comprising a variable bending stiffness portion having bending stiffnesses which increase in respect of axial distance, the method comprising:

• (a) providing the cardiac stimulator;
• (b) providing the medical electrical lead;
• (c) transvenously inserting and positioning the lead through a coronary sinus and into a coronary vein in the heart,
• (d) operatively connecting the connector of the lead to the cardiac stimulator;
• and
• (e) delivering at least one electrical pulse originating in the cardiac stimulator through the lead and the at least one electrode to the heart.

A method of electrically stimulating a patient's heart with an implantable cardiac stimulator and an elongated implantable medical electrical lead, the lead comprising a lead body having proximal and distal sections, at least one electrode for sensing or electrically stimulating the heart, a proximal end comprising an electrical connector, the connector being contiguous with the proximal section of the lead body, a distal end connected to the distal section of the lead body, at least one electrical conductor having proximal and distal ends, the distal end of the conductor being operatively connected to the at least one electrode, the proximal end of the conductor being operatively connected to the electrical connector, the distal section of the lead body comprising at least first and second segments, the first segment having a bending stiffness Sb1, the second segment having a bending stiffness Sb2, Sb1 not equaling Sb2, the first segment, and the second segment being configured and characterized such that a distally directed force is imparted to the distal end of the lead when the first and second segments are subjected to a bending moment resulting in a sufficient curvature of the distal section of the lead body, the bending moment being provided by an external force applied to the lead, the first segment being located distally in respect of the second segment, the distal section of the lead body having an outer diameter ranging between about 0.5 mm and about 3 mm, the lead being adapted, sized and configured for placement in one or more of a coronary vein, a coronary sinus and a right atrial appendage, the method comprising:

• (a) providing the cardiac stimulator;
• (b) providing the medical electrical lead;
• (c) transvenously inserting and positioning the lead through a coronary sinus and into a coronary vein in the heart,
• (d) operatively connecting the connector of the lead to the cardiac stimulator;
• and
• (e) delivering at least one electrical pulse originating in the cardiac stimulator through the lead and the at least one electrode to the heart.