Automatic detection of defibrillation lead

An implantable apparatus for treating cardiac arrhythmia, the apparatus comprising:

• a plurality of electrical leads for sensing cardiac signals and delivering high and low energy therapy;
• high energy shocking lead electrodes distributed around multiple regions of a heart, including a superior vena cava region, a coronary sinus region, and a right ventricle region;
• a conductive housing covering a part of the apparatus adaptable to be an electrode;
• an impedance measurement circuit connected to the plurality of leads and the conductive housing wherein the impedance circuit is adaptable to measure the impedance between sets of electrodes;
• a comparison circuit connected to the impedance circuit, wherein the comparison circuit compares the measured impedance values to a predetermined range including an upper boundary value and a lower boundary value;
• a lead electrode status indicator circuit, wherein the lead electrode status indicator circuit is in an active state when the measured impedance between sets of high-energy shocking electrodes is within the predetermined range;
• and
• a processor connected to the impedance measurement circuit and the output of the lead electrode status indicator circuit, wherein the processor is adaptable to change the electrode combination that delivers the therapy.

A method comprising:

• measuring an impedance between first and second lead electrodes;
• comparing a value of the measured impedance to a predetermined range including an upper boundary value and a lower boundary value to detect whether a high-energy shocking lead is present;
• and
• activating a lead electrode status indicator when the impedance is within the range indicating a presence among the first and second lead electrodes of a high-energy shocking lead electrode.

A system for treating cardiac arrhythmia comprising:

• an external programmer;
• and
• an implantable apparatus for treating cardiac arrhythmia, the implantable apparatus capable of determining status of a high-energy shocking electrode by an impedance measurement;
• wherein the implantable apparatus communicates the status of an electrode set to the external programmer and the external programmer allows or disallows selection of a therapy combination involving that electrode set depending on the status of the electrode set.