Method and apparatus for termination of tachyarrhythmias

An implantable cardioversion/defibrillation system, comprising:

• an implantable cardioverter/defibrillator comprising means for generating biphasic output pulses;
• a plurality of cardioversion/defibrillation electrodes, coupled to said pulse generating means, said electrodes comprising a first electrode portion displaying essentially equal attenuation of positive and negative voltage pulses and a second electrode portion displaying differential attenuation of positive and negative voltage pulses.

A implantable medical lead, comprising:

• an elongated insulative lead body carrying a cardioversion/defibrillation electrode, wherein the cardioversion/defibrillation electrode comprises a first portion displaying essentially equal attenuation of positive and negative voltage pulses and a second portion having an exterior surface of tantalum oxide.

An implantable cardioversion/defibrillation system, comprising:

• an implantable cardioverter/defibrillator comprising means for generating biphasic output pulses;
• a plurality of cardioversion/defibrillation electrodes, coupled to said pulse generating means, said electrodes comprising a first electrode portion displaying essentially equal attenuation of positive and negative voltage pulses and a second electrode portion having an exterior surface of tantalum oxide.

A method of fabricating a cardioversion/defibrillation lead, comprising:

• selecting a metal member fabricated of a first material capable of displaying unequal attenuation of positive and negative voltage pulses, coated with a second material displaying essentially equal attenuation of positive and negative voltage pulses;
• removing a portion of said second material to expose a portion of said first material;
• mounting said member to an insulative lead body and coupling said member to a conductor located within said lead body.

A method of fabricating a cardioversion/defibrillation lead, comprising:

• selecting a metal member fabricated of a first material capable of displaying unequal attenuation of positive and negative voltage pulses;
• coating a portion of said first material with a second material displaying essentially equal attenuation of positive and negative voltage pulses;
• mounting said member to an insulative lead body and coupling said member to a conductor located within said lead body.