Transvascular nerve stimulation apparatus and methods

1. A system for stimulating a left phrenic nerve and a right phrenic nerve of a patient, the system comprising:

a signal generator to produce stimulation signals;

a lead structure configured for insertion into a venous system of the patient, the lead structure defining a longitudinal axis along a length of the lead structure and between a proximal portion of the lead structure and a distal portion of the lead structure, and the lead structure having a plurality of leads along the longitudinal axis to receive stimulation signals from the signal generator;

a plurality of second pairs of electrodes on the lead structure proximate the distal portion of the lead structure, wherein the plurality of second pairs of electrodes includes second electrodes configured to receive stimulation signals from at least one lead of the plurality of leads for stimulation of the right phrenic nerve;

a plurality of first pairs of electrodes on the lead structure proximate the proximal portion of the lead structure wherein the plurality of first pairs of electrodes includes first electrodes configured to receive stimulation signals from at least one lead of the plurality of leads for stimulation of the left phrenic nerve, wherein the signal generator is proximal to the first electrodes;

a blood chemistry sensor for insertion into a blood vessel proximate at least one of the first electrodes and the second electrodes, the blood chemistry sensor configured to sense a condition of blood of the patient, wherein the signal generator adjusts the stimulation signals based on the sensed condition of blood;

a motion sensor configured to sense motion of the patient, wherein the signal generator adjusts the stimulation signals based on the sensed motion; and a control system programmed to (a) select the first electrodes from the plurality of first pairs of electrodes to stimulate the left phrenic nerve, and (b) select the second electrodes from the plurality of second pairs of electrodes to stimulate the right phrenic nerve.

2. The system of claim 1 , wherein the blood chemistry sensor is at least one of a blood oxygen concentration sensor and a blood CO 2 concentration sensor.

3. The system of claim 2 , wherein the signal generator changes an intensity of the stimulation signals when the blood chemistry sensor senses at least one of a low blood oxygen concentration and a high blood CO 2 concentration.

4. The system of claim 1 , wherein the motion sensor is one of an accelerometer or an inclinometer.

5. The system of claim 4 , wherein the signal generator changes the intensity of the stimulation signals when the motion sensor senses changes in motion of the patient.

6. The system of claim 1 , further comprising:

wherein the first electrodes include two electrodes best positioned, relative to other electrodes of the first pairs of electrodes, to stimulate the left phrenic nerve, and wherein the second electrodes include two electrodes best positioned, relative to other electrodes of the second pairs of electrodes, to stimulate the right phrenic nerve.

7. The system of claim 1 , wherein the control system is programmed to select the second electrodes by determining that the second electrodes have a stimulation efficacy for the right phrenic nerve that is greater than a stimulation efficacy of any of the other electrodes of the second pairs of electrodes.

8. The system of claim 1 , wherein the control system is programmed to cause the signal generator to produce stimulation signals for delivery to the first electrodes and the second electrodes approximately simultaneously.

9. The system of claim 1 , wherein the signal generator is configured to be implantable in the patient.

10. The system of claim 1 , wherein the distal portion of the lead structure has a first configuration for insertion of the lead structure into a venous system of the patient, and a second configuration, different than the first configuration, for urging the second electrodes toward an inner wall of a superior vena cava.

11. The system of claim 10 , wherein the distal portion of the lead structure expands from the first configuration to the second configuration.

12. The system of claim 10 , wherein, when the lead structure is in the second configuration, the second electrodes are configured to be proximate multiple circumferentially spaced points of the inner wall of the superior vena cava.

13. A system for stimulating a left phrenic nerve and a right phrenic nerve of a patient, the system comprising:

a signal generator to produce stimulation signals;

a lead structure configured for insertion into (a) at least one of a left jugular vein and a left subclavian vein, (b) a left brachiocephalic vein, and (c) a vena cava of the patient, the lead structure defining a longitudinal axis along a length of the lead structure and having a plurality of leads to receive stimulation signals from the signal generator;

a plurality of second pairs of electrodes along the longitudinal axis of the lead structure proximate a distal portion of the lead structure and configured to receive stimulation signals from at least one lead of the plurality of leads;

a plurality of first pairs of electrodes along the longitudinal axis of the lead structure proximal to the plurality of second pairs of electrodes, the plurality of first pairs of electrodes configured to receive stimulation signals from at least one lead of the plurality of leads, wherein the signal generator is proximal to the first pairs of electrodes; and

a control system programmed to (a) select a first stimulation pair of electrodes from the plurality of first pairs of electrodes to stimulate the left phrenic nerve, and (b) select a second stimulation pair of electrodes from the plurality of second pairs of electrodes to stimulate the right phrenic nerve.

14. The system of claim 13 , wherein the plurality of second pairs of electrodes comprises at least two pairs of electrodes.

15. The system of claim 14 , wherein the second stimulation pair of electrodes is one of the at least two pairs of electrodes, and the control system is programmed to select the second stimulation pair of electrodes from the at least two pairs of electrodes.

16. The system of claim 15 , wherein the control system is programmed to select the second stimulation pair of electrodes by determining that the second stimulation pair of electrodes has a stimulation efficacy for the right phrenic nerve that is greater than a stimulation efficacy of any of the other pairs of electrodes of the at least two pairs of electrodes.

17. The system of claim 13 , wherein the first stimulation pair of electrodes includes a first electrode and a second electrode, and the first electrode and the second electrode are aligned along a line generally parallel to the left phrenic nerve, and wherein the second stimulation pair of electrodes includes a third electrode and a fourth electrode, and the third electrode and the fourth electrode are aligned along a line generally parallel to the right phrenic nerve.

18. The system of claim 13 , wherein the control system is programmed to cause the signal generator to produce stimulation signals for delivery to the first and second stimulation pair of electrodes approximately simultaneously.

19. The system of claim 13 , wherein the signal generator is configured to be implantable in the patient.

20. The system of claim 13 , wherein the distal portion of the lead structure has a first configuration for insertion of the lead structure through an insertion point of a blood vessel and a second configuration, different than the first configuration, for urging the plurality of second pairs of electrodes toward an inner wall of the superior vena cava.

21. The system of claim 20 , wherein the distal portion of the lead structure expands from the first configuration to the second configuration.

22. The system of claim 20 , wherein the distal portion of the lead structure is biased to the second configuration.

23. The system of claim 20 , wherein, when the lead structure is in the second configuration, the plurality of second pairs of electrodes are configured to be proximate to multiple circumferentially spaced points of the inner wall of the superior vena cava.

24. The system of claim 13 , further comprising:

a blood chemistry sensor for insertion in a blood vessel proximate at least one of the plurality of first pairs of electrodes and the plurality of second pairs of electrodes, the blood chemistry sensor configured to sense a condition of blood of the patient, wherein the signal generator adjusts the stimulation signals based on the sensed condition of blood; and

a motion sensor configured to sense motion of the patient, wherein the signal generator adjusts the stimulation signals based on the sensed motion.

25. The system of claim 24 , wherein the blood chemistry sensor is at least one of a blood oxygen concentration sensor and a blood CO 2 concentration sensor, and the signal generator changes an intensity of the stimulation signals when the blood chemistry sensor senses at least one of a low blood oxygen concentration and a high blood CO 2 concentration.

26. The system of claim 24 , wherein the motion sensor is one of an accelerometer or an inclinometer, and the signal generator changes an intensity of the stimulation signals when the motion sensor senses a change in motion of the patient.

27. The system of claim 13 , wherein the first stimulation pair of electrodes includes a source electrode and a sink electrode a sink electrode.

28. The system of claim 13 , wherein the plurality of leads connect the plurality of first pairs of electrodes and the plurality of second pairs of electrodes to the signal generator.