Fatigue resistant design for leads employing multi-strand cables as primary conductors

A lead comprising:

• a tubular body including a flex-strain relief segment and a conventional body segment;
• and
• a conductor cable including a first length and a second length, the first length extending helically about a longitudinal axis of the tubular body through the flex-strain relief segment, the second length joining the first length and extending longitudinally along the conventional body segment of the tubular body in a generally linear fashion;
• wherein the flex-strain relief segment includes a flexible core, wherein the flexible core comprises a locating feature that is coaxial to the tubular body and offset in a radial direction from the tubular body, and wherein the locating feature is angled relative to the longitudinal axis and assists in providing a helical pitch for the first length.

A lead for connecting to a pacing and/or defibrillation power source, the lead comprising

• a lead tubular body;
• a power source connector for connecting the lead to the power source;
• and
• a strain-flex relief assembly joining the lead tubular body to the power source connector, wherein the strain-flex assembly includes:
• a helical cable conductor configuration;
• and
• a flexible core, wherein at least a portion of the flexible core is shaped into at least two locating features spaced apart from each other along the length of the flexible core, the at least two locating features each receiving a portion of the helical cable conductor configuration.

A lead for connecting to a pacing and/or defibrillation power source, the lead comprising:

• a lead tubular body;
• a power source connector for connecting the lead to the power source;
• and
• a strain-flex relief assembly joining the lead tubular body to the power source connector assembly, wherein the strain-flex assembly includes:
• a cable conductor;
• and
• a flexible core, at least a portion of which is shaped into a location feature for receiving the cable conductor and maintaining the cable conductor in a helical configuration, wherein the location feature has a length, as measured in a direction generally parallel to a longitudinal axis of the flexible core, that is less than a length of the longitudinal axis of the flexible core.