Muscle and nerve stimulation

1. An implantable medical device comprising:

a. an intravascularly implantable cardiac lead configured for stimulating cardiac tissue;

b. an intravascularly implantable respiration lead configured for transvascularly stimulating a phrenic nerve;

c. an intravascularly implantable intercostal lead with at least one electrode configured to be located in an intercostal vein;

d. an implantable medical device with at least one external electrode configured to be implanted subcutaneously in a patient's chest;

e. circuitry within the implantable medical device configured to measure impedance between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of a patient and the at least one electrode on the implantable medical device when the device implanted subcutaneously in the patient; and

f. circuitry within the implantable medical device configured to stimulate the phrenic nerve using the stimulation electrode.

2. The lead system of claim 1 , wherein:

a. the cardiac lead is selected from a group consisting of a pacemaker lead, a defibrillation leads, and a CRT lead; and

b. the respiration lead is installed in a pericardiophrenic vein.

3. The lead system of claim 1 , wherein:

a. the cardiac lead is selected from a group consisting of a pacemaker lead, a defibrillation lead, and a CRT lead; and

b. the respiration lead is installed in a brachiocephalic vein.

4. The lead system of claim 3 , wherein the respiration lead has pre-formed biases that assist in stabilizing the lead in the vein and positioning electrodes on the lead proximate a phrenic nerve.

5. The lead system of claim 1 , wherein:

a. cardiac lead is selected from a group consisting of a pacemaker lead, a defibrillation leads, and a CRT lead; and

b. the respiration lead is installed in an internal jugular vein.

6. The lead system of claim 5 , wherein the respiration lead has pre-formed biases that assist in stabilizing the lead in the vein and positioning electrodes on the lead proximate a phrenic nerve.

7. The lead system of claim 1 , wherein:

a. the cardiac lead is selected from a group consisting of a pacemaker lead, a defibrillation lead, and a CRT lead; and

b. the respiration lead is installed in a superior intercostal vein.

8. A respiration sensing and stimulation system for use with an implantable medical device comprising:

a. an intravascular intercostal lead with at least one electrode configured to be located in an intercostal vein;

b. an implantable medical device with at least one electrode configured to be implanted subcutaneously in a patient's chest;

c. circuitry within the implantable medical device configured to measure impedance between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of a patient and the at least one electrode on the implantable medical device when the device implanted subcutaneously in the patient;

d. at least one stimulation electrode that is configured to be positioned proximate a phrenic nerve; and

e. circuitry within the implantable medical device configured to stimulate the phrenic nerve using the stimulation electrode.

9. The respiration sensing system of claim 8 , wherein the intercostal vein is a superior intercostal vein.

10. The respiration sensing system of claim 8 , wherein at least one electrode on the intercostal lead is configured to be located proximate a diaphragm and the circuitry is configured to sample impedance measurements between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device when the device is implanted subcutaneously in the patient at a first interval and the circuitry is further configured to sample diaphragmatic EMG at the electrode proximate the diaphragm when the electrode is located in an intercostal vein of the patient at a second or offset interval so that samples of impedance and EMG can be taken at separate times.

11. The respiration sensing system of claim 8 , wherein at least one electrode on the intercostal lead is configured to be located proximate a diaphragm and the circuitry is configured to sample impedance measurements between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device when the device is implanted subcutaneously in the patient at a first interval and the circuitry is further configured to sample electrocardiogram measurements between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device when the device is implanted subcutaneously in the patient at a second or offset interval so that samples of impedance and electrocardiogram measurements can be taken at separate times.

12. The respiration sensing system of claim 8 , wherein at least one electrode on the intercostal lead is configured to be located proximate a diaphragm and the circuitry is configured to sample impedance measurements between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device when the device is implanted subcutaneously in the patient at a first interval and is configured to sample diaphragmatic EMG at an electrode proximate the diaphragm at a second interval and is configured to sample electrocardiogram measurements between the at least one electrode on the intercostal lead when the electrode is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device when the device is implanted subcutaneously in the patient at a third interval so that samples of each of the three measurements can be taken at separate times.

13. A sensing and stimulation system comprising:

a. an intravascular intercostal lead with at least two electrodes configured to be located in an intercostal vein proximate a diaphragm;

b. circuitry that is configured to sample measurements of diaphragmatic EMG based on signals received by the at least two electrodes when the electrodes are located in an intercostal vein of a patient;

c. at least one stimulation electrode that is configured to be positioned proximate a phrenic nerve on the same intercostal lead as the other electrodes; and

d. circuitry within the implantable medical device configured to stimulate the phrenic nerve using the stimulation electrode.

14. The sensing system of claim 13 , further comprising an implantable medical device having at least one electrode configured to be implanted subcutaneously in a patient's chest and circuitry that is configured to sample electrocardiogram measurements between at least one electrode on the intercostal lead when the electrode on the intercostal lead is located in an intercostal vein of the patient and the at least one electrode on the implantable medical device at an interval so that samples of diaphragmatic EMG and electrocardiogram signals can be taken at separate times.

15. A method of modifying and detecting respiration by stimulating a phrenic nerve and sensing impedance between an electrode located on a lead and disposed in an intercostal vein of a patient and a second electrode located elsewhere in the patient.

16. The method of claim 15 , wherein the second electrode is located on an implantable medical device that contains circuitry configure to sense the impedance between the electrodes and stimulate the phrenic nerve.

17. The method of claim 15 , wherein the second electrode is located on a second lead implanted in a brachiocephalic vein.