Vagal stimulation for anti-embolic therapy

• US 20060271115A1
• Filed: 06/10/2004
• Published: 11/30/2006
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: BioControl Medical (B.C.M) Ltd.
• Inventors: Cohen, Ehud, Ben-David, Tamir, Ben-Ezra, Omry
• Granted Patent: US 7,885,711 B2
• Time in Patent Office: Days
• US Class Current: 607/5
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/39624 Pain reduction therapy

Abstract

Apparatus (20) for treating a subject (30) suffering from spontaneous atrial fibrillation includes an electrode device (22), adapted to be coupled to a site of the subject (30) selected from the list consisting of: a vagus nerve (24) of the subject (30), an epicardial fat pad of the subject (30), a pulmonary vein of the subject (30), a carotid artery of the subject (30), a carotid sinus of the subject (30), a vena cava vein of the subject (30), and an internal jugular vein of the subject (30), and a control unit (32), adapted to drive the electrode device (22) to apply an electrical current to the site, and to configure the current to maintain the spontaneous AF for at least about 24 hours, so as to modify blood flow within the atria and reduce risk of thromboembolic events.

Claims

1-20. -20. (canceled)

21. Treatment apparatus, comprising:

an electrode device, adapted to be coupled to tissue of a subject; and

a control unit, adapted to;

drive the electrode device to apply an electrical current to the tissue, and

configure the current to modify atrial motion of the subject to a level sufficient to reduce a risk of an occurrence of a thromboembolic event.

22. Apparatus according to claim 21, wherein the control unit is adapted to configure the current to modify blood flow within an atrium of the subject.

23. Apparatus according to claim 21, wherein the electrode device is adapted to be coupled to the tissue of the subject, the subject suffering from atrial fibrillation (AF) or from increased risk of thromboembolic events.

24. Apparatus according to claim 21, wherein the control unit is adapted to configure the current to increase blood flow out of a left atrial auricle of the subject.

25. Apparatus according to claim 21, comprising a sensor adapted to detect an occurrence of atrial fibrillation (AF) and generate a sensor signal responsive thereto, wherein the control unit is adapted to receive the sensor signal, and to drive the electrode device to apply the current during the occurrence of the AF.

26. Apparatus according to claim 21, comprising a sensor adapted to detect an occurrence of atrial fibrillation (AF) and generate a sensor signal responsive thereto, wherein the control unit is adapted to drive the electrode device to apply the current in the absence of the occurrence of the AF.

27. Apparatus according to claim 21, wherein the tissue includes cardiac tissue of the subject, and wherein the electrode device is adapted to be coupled to the cardiac tissue.

28. Apparatus according to claim 21, wherein the tissue is selected from the list consisting of atrial tissue, cardiac fat pad tissue, a pulmonary vein, a carotid artery, a carotid sinus, a vena cava vein, and an internal jugular vein, and wherein the electrode device is adapted to be coupled to the selected tissue.

29. Apparatus according to claim 21, wherein the tissue includes a vagus nerve of the subject, and wherein the electrode device is adapted to be coupled to the vagus nerve.

30. Apparatus according to claim 29,

wherein the control unit is adapted to configure the current to include a stimulating current, which is capable of inducing action potentials in a first set and a second set of nerve fibers of the vagus nerve, and an inhibiting current, which is capable of inhibiting the induced action potentials traveling in the second set of nerve fibers, the nerve fibers in the second set having generally larger diameters than the nerve fibers in the first set, and

wherein the control unit is adapted to drive the electrode device to apply the stimulating current and the inhibiting current to the vagus nerve.

31. Apparatus according to claim 29,

wherein the control unit is adapted to configure the current to include a stimulating current, which is capable of inducing action potentials in the vagus nerve, and an inhibiting current, which is capable of inhibiting device-induced action potentials traveling in the vagus nerve in an afferent direction toward a brain of the subject, and

wherein the control unit is adapted to drive the electrode device to apply the stimulating current and the inhibiting current to the vagus nerve.

32. Apparatus according to claim 29, wherein the control unit is adapted to:

during a first stimulation period, configure the current to cause a reduction in a force of contraction of atrial cells of the subject, and

during a second stimulation period, configure the current to cause an increase in the reduced force of contraction of the atrial cells.

33. Apparatus according to claim 32, wherein the control unit is adapted to set the first stimulation period to have a duration of between about 100 milliseconds and about 1000 milliseconds.

34. Apparatus according to claim 32, wherein the control unit is adapted to set the second stimulation period to have a duration of between about 200 milliseconds and about 15 seconds.

35. Apparatus according to claim 32, wherein the control unit is adapted to configure the current to have a first frequency during the first stimulation period, and a second frequency during the second stimulation period, the first frequency greater than the second frequency.

36. Apparatus according to claim 32, wherein the control unit is adapted to configure the current to have a first amplitude during the first stimulation period, and a second amplitude during the second stimulation period, the first amplitude greater than the second amplitude.

37. Apparatus according to claim 32, wherein the control unit is adapted to:

drive the electrode device to apply the current during the first stimulation period, and

withhold the electrode device from applying the current during the second stimulation period.

38. Apparatus according to claim 32, wherein the control unit is adapted to:

during the first stimulation period, configure the current so as to induce action potentials in the vagus nerve, and

during the second stimulation period, configure the current so as to block action potentials in the vagus nerve.

39. Apparatus according to claim 32, wherein the control unit is adapted to configure the current so as to induce action potentials in the vagus nerve during the first and the second stimulation periods.

40. Apparatus according to claim 32, wherein the control unit is adapted to:

drive the electrode device to apply the current in respective bursts in each of a plurality of cardiac cycles of the subject, and

configure each pulse of each of the bursts to have a pulse width of at least a first pulse width during the first stimulation period, and to have a pulse width of less than a second pulse width during the second stimulation period, the first pulse width being greater than or equal to the second pulse width.

41. Apparatus according to claim 32, wherein the control unit is adapted to:

drive the electrode device to apply the current in respective bursts in each of a plurality of cardiac cycles of the subject, and

configure each of the bursts to have a number of pulses of at least a first number of pulses during the first stimulation period, and to have a number of pulses of less than a second number of pulses during the second stimulation period, the first number of pulses being greater than or equal to the second number of pulses.

42. Apparatus according to claim 32, comprising a sensor, adapted to sense at least one physiological variable of the subject, and to generate a sensor signal responsive thereto, and wherein the control unit is adapted to receive the sensor signal and to synchronize therewith a commencement of at least one of the first and second stimulation periods.

43. Apparatus according to claim 42, wherein the sensed physiological variable includes a QRS-complex of the subject, and wherein the control unit is adapted to initiate the first stimulation period within about 50 milliseconds after an occurrence of the QRS-complex.

44. Apparatus according to claim 42, wherein the sensed physiological variable includes an expiration by the subject, and wherein the control unit is adapted to initiate the first stimulation period within about 500 milliseconds after a beginning of the expiration.

45. Apparatus according to claim 42, wherein the sensed physiological variable includes diastole of the subject, and wherein the control unit is adapted to initiate the second stimulation period substantially simultaneously with a portion of the diastole.

46-163. -163. (canceled)

164. A treatment method, comprising:

applying an electrical current to tissue of a subject; and

configuring the current to modify atrial motion of the subject to a level sufficient to reduce a risk of an occurrence of a thromboembolic event.

165. A method according to claim 164, wherein configuring the current comprises configuring the current to modify blood flow within an atrium of the subject.

166. A method according to claim 164, comprising identifying that the subject is suffering from atrial fibrillation (AF) or from increased risk of thromboembolic events.

167. A method according to claim 164, wherein configuring the current comprises configuring the current to increase blood flow out of a left atrial auricle of the subject.

168. A method according to claim 164, wherein applying the current comprises applying the current during an occurrence of atrial fibrillation.

169. A method according to claim 164, wherein applying the current comprises applying the current in the absence of atrial fibrillation.

170. A method according to claim 164, wherein the tissue includes cardiac tissue of the subject, and wherein applying the current comprises applying the current to the cardiac tissue.

171. A method according to claim 164, wherein the tissue is selected from the list consisting of atrial tissue, cardiac fat pad tissue, a pulmonary vein, a carotid artery, a carotid sinus, a vena cava vein, and an internal jugular vein, and wherein applying the current comprises applying the current to the selected tissue.

172. A method according to claim 164, wherein the tissue includes a vagus nerve of the subject, and wherein applying the current comprises applying the current to the vagus nerve.

173. A method according to claim 172,

wherein applying the current comprises applying a stimulating current and an inhibiting current, and

wherein configuring the current comprises configuring the stimulating current to induce action potentials in a first set and a second set of nerve fibers of the vagus nerve, and configuring the inhibiting current to inhibit the induced action potentials traveling in the second set of nerve fibers, the nerve fibers in the second set having generally larger diameters than the nerve fibers in the first set.

174. A method according to claim 172,

wherein applying the current comprises applying a stimulating current and an inhibiting current, and

wherein configuring the current comprises configuring the stimulating current to induce action potentials in the vagus nerve, and configuring the inhibiting current to inhibit action potentials induced by the stimulating current and traveling in the vagus nerve in an afferent direction toward a brain of the subject.

175. A method according to claim 172, wherein configuring the current comprises:

during a first stimulation period, configuring the current to cause a reduction in a force of contraction of atrial cells of the subject; and

during a second stimulation period, configuring the current to cause an increase in the reduced force of contraction of the atrial cells.

176. A method according to claim 175, wherein configuring the current comprises setting the first stimulation period to have a duration of between about 100 milliseconds and about 1000 milliseconds.

177. A method according to claim 175, wherein configuring the current comprises setting the second stimulation period to have a duration of between about 200 milliseconds and about 15 seconds.

178. A method according to claim 175, wherein configuring the current comprises configuring the current to have a first frequency during the first stimulation period, and a second frequency during the second stimulation period, the first frequency greater than the second frequency.

179. A method according to claim 175, wherein configuring the current comprises configuring the current to have a first amplitude during the first stimulation period, and a second amplitude during the second stimulation period, the first amplitude greater than the second amplitude.

180. A method according to claim 175, wherein applying the current comprises:

applying the current during the first stimulation period; and

withholding applying the current during the second stimulation period.

181. A method according to claim 175, wherein configuring the current comprises:

during the first stimulation period, configuring the current so as to induce action potentials in the vagus nerve; and

during the second stimulation period, configuring the current so as to block action potentials in the vagus nerve.

182. A method according to claim 175, wherein configuring the current comprises configuring the current so as to induce action potentials in the vagus nerve during the first and the second stimulation periods.

183. A method according to claim 175,

wherein applying the current comprises applying the current in respective bursts in each of a plurality of cardiac cycles of the subject, and

wherein configuring the current comprises configuring each pulse of each of the bursts to have a pulse width of at least a first pulse width during the first stimulation period, and to have a pulse width of less than a second pulse width during the second stimulation period, the first pulse width being greater than or equal to the second pulse width.

184. A method according to claim 175,

wherein applying the current comprises applying the current in respective bursts in each of a plurality of cardiac cycles of the subject, and

wherein configuring the current comprises configuring each of the bursts to have a number of pulses of at least a first number of pulses during the first stimulation period, and to have a number of pulses of less than a second number of pulses during the second stimulation period, the first number of pulses being greater than or equal to the second number of pulses.

185. A method according to claim 175, comprising sensing at least one physiological variable of the subject, wherein configuring the current comprises synchronizing a commencement of at least one of the first and second stimulation periods with the sensed physiological variable.

186. A method according to claim 185, wherein the sensed physiological variable includes a QRS-complex of the subject, and wherein configuring the current comprises initiating the first stimulation period within about 50 milliseconds after an occurrence of the QRS-complex.

187. A method according to claim 185, wherein the sensed physiological variable includes an expiration by the subject, and wherein configuring the current comprises initiating the first stimulation period within about 500 milliseconds after a beginning of the expiration.

188. A method according to claim 185, wherein the sensed physiological variable includes diastole of the subject, and wherein configuring the current comprises initiating the second stimulation period substantially simultaneously with a portion of the diastole.

189-360. -360. (canceled)