Heart treatment apparatus and heart treatment method

• US 20070118178A1
• Filed: 08/19/2004
• Published: 05/24/2007
• Est. Priority Date: 08/26/2003
• Status: Active Grant

• Current Assignee: Terumo Kabushiki Kaisha (Terumo Corporation)
• Original Assignee: Terumo Corporation
• Inventors: Fukui, Yoshihito
• Granted Patent: US 7,881,788 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions

Abstract

Precursor of fatal arrhythmia is detected and by setting the tolerance level for carrying out nerve stimulation depending on the severity degree of the precursor, significant variation of the heart rate is suppressed and induction of the fatal arrhythmia is repressed. For this purpose, precursor of tachyarrhythmia occurrence such as premature contraction, ST change, repolarization abnormality or the like is detected and the lower-limit of the atrium interval which becomes the tolerance level of the nerve stimulation is set according to the detected result. Then, it is constituted according to the precursor of aforesaid tachyarrhythmia such that time for making the nerve stimulation means in an operation state is to be adjusted or nerve stimulation is to be carried out as much as the heart rate of a predetermined number of times.

Claims

1. A heart treatment apparatus comprising:

nerve stimulation means for generating a nerve stimulation signal which stimulates a vagus nerve;

tachyarrhythmia precursor detection means for detecting a precursor of a tachyarrhythmia occurrence;

heart activity measuring means for measuring a heart activity;

means for defining a tolerance level of said heart activity; and

control means for connecting said nerve stimulation means and said tachyarrhythmia precursor detection means to said heart activity measuring means, wherein

said control means controls said nerve stimulation means such that the output of said heart activity measuring means is to be maintained within said tolerance level in response to said tachyarrhythmia precursor detection means.

2. A heart treatment apparatus according to claim 1, wherein the precursor detection of said tachyarrhythmia occurrence is carried out according to an electrogram.

3. A heart treatment apparatus according to claim 2, wherein the precursor of said tachyarrhythmia occurrence is any one of premature contraction, ST change and repolarization abnormality.

4. A heart treatment apparatus according to claim 1, wherein control of said nerve stimulation means, which responded to said tachyarrhythmia precursor detection means, is carried out for a predetermined period.

5. A heart treatment apparatus according to claim 4, wherein said predetermined period is adjusted according to the output of said tachyarrhythmia precursor detections means.

6. A heart treatment apparatus according to claim 1, wherein control of said nerve stimulation means, which responded to said tachyarrhythmia precursor detection means, is carried out for a period until said heart activity reaches a predetermined number of times.

7. A heart treatment apparatus according to claim 6, wherein said predetermined number of times is adjusted according to the output of said tachyarrhythmia precursor detection means.

8. A heart treatment apparatus according to claim 1, wherein when the output of said heart activity measuring means is out of said tolerance level, said nerve stimulation means generates said nerve stimulation signal.

9. A heart treatment apparatus according to claim 8, wherein when the output of said heart activity measuring means is out of said tolerance level, said nerve stimulation signal parameter which said nerve stimulation means generates is adjusted according to difference between the output of said heart activity measuring means and said tolerance level.

10. A heart treatment apparatus according to claim 9, wherein said nerve stimulation signal parameter is at least one of period between pulses, pulse width, number of pulses, pulse current, pulse voltage, delay time, rest time and repetition times or a combination of a plurality of ones selected from these.

11. A heart treatment apparatus according to claim 1, wherein said heart activity is heartbeats.

12. A heart treatment apparatus according to claim 11, wherein heartbeat measurement by said heart activity measuring means is measurement of heartbeat interval or heart rate.

13. A heart treatment apparatus according to claim 12, wherein said tolerance level is defined to a heartbeat interval range longer than a predetermined lower-limit of a heartbeat interval or to a heart rate range lower than said predetermined upper-limit of a heart rate.

14. A heart treatment apparatus to claim 13, wherein said lower-limit of heartbeat interval or said upper limit of heart rate is adjusted according to the output of said tachyarrhythmia precursor detection means.

15. A heart treatment apparatus according to claim 14, wherein said lower-limit of heartbeat interval is adjusted to be longer than a heartbeat interval at a normal time or said upper-limit of heart rate is adjusted to be lower than a heart rate at a normal time.

16. A heart treatment apparatus according to claim 15, wherein said lower-limit of heartbeat interval is adjusted to be longer than a heartbeat interval at a normal time by a predetermined amount or said upper-limit of heart rate is adjusted to be lower than a heart rate at a normal time by a predetermined amount.

17. A heart treatment apparatus according to claim 16, wherein said predetermined amount is a fixed value.

18. A heart treatment apparatus according to claim 17, wherein said predetermined amount is a function of a heartbeat interval at a normal time or of a heart rate at a normal time.

19. A heart treatment apparatus according to claim 18, wherein said function is a predetermined ratio of a heartbeat interval at a normal time or of a heart rate at a normal time.

20. Heart treatment method comprising:

a nerve stimulation step for generating a nerve stimulation signal which stimulates a vagus nerve;

a step for detecting a precursor of a tachyarrhythmia occurrence;

a step for measuring a heart activity and;

a step for defining a tolerance level of said heart activity, wherein

said nerve stimulation is controlled such that the measured output of said heart activity is to be maintained within said tolerance level in response to the precursor detection of said tachyarrhythmia occurrence.

21. Heart treatment method according to claim 20, wherein the precursor detection of said tachyarrhythmia occurrence is carried out according to an electrogram.

22. Heart treatment method according to claim 21, wherein the precursor of said tachyarrhythmia occurrence is any one of premature contraction, ST change and repolarization abnormality.

23. Heart treatment method according to claim 20, wherein said nerve stimulation in response to the precursor detection of said tachyarrhythmia occurrence is carried out for a predetermined period.

24. Heart treatment method according to claim 23, wherein said predetermined period is adjusted according to the precursor detection of said tachyarrhythmia occurrence.

25. Heart treatment method according to claim 20, wherein said nerve stimulation which responded to the precursor detection of said tachyarrhythmia occurrence is carried out for a period until said heart activity reaches a predetermined number of times.

26. Heart treatment method according to claim 25, wherein said predetermined number of times is adjusted according to the precursor detection of said tachyarrhythmia occurrence.

27. Heart treatment method according to claim 20, wherein said nerve stimulation signal is generated when the measured output of said heart activity is out of said tolerance level.

28. Heart treatment method according to claim 27, wherein said nerve stimulation signal parameter is adjusted according to difference between the measured output of said heart activity and said tolerance level when the measured output of said heart activity is out of said tolerance level.

29. Heart treatment method according to claim 28, wherein said nerve stimulation signal parameter is at least one of period between pulses, pulse width, number of pulses, pulse current, pulse voltage, delay time, rest time and repetition times or a combination of a plurality of ones selected from these.

30. Heart treatment method according to claim 20, wherein said heart activity is heartbeats.

31. Heart treatment method according to claim 30, wherein said heartbeat measurement is measurement of heartbeat interval or heart rate.

32. Heart treatment method according to claim 31, wherein said tolerance level is defined to a heartbeat interval range longer than a predetermined lower-limit of a heartbeat interval or to a heart rate range lower than said predetermined upper-limit of a heart rate.

33. Heart treatment method according to claim 32, wherein said lower-limit of heartbeat interval or said upper-limit of heart rate is adjusted according to said tachyarrhythmia precursor detection.

34. Heart treatment method according to claim 33, wherein said lower-limit of heartbeat interval is adjusted to be longer than a heartbeat interval at a normal time or said upper-limit of heart rate is adjusted to be lower than a heart rate at a normal time.

35. Heart treatment method according to claim 34, wherein said lower-limit of heartbeat interval is adjusted to be longer than a heartbeat interval at a normal time by a predetermined amount or said upper-limit of heart rate is adjusted to be lower than a heart rate at a normal time by a predetermined amount.

36. Heart treatment method according to claim 35, wherein said predetermined amount is a fixed value.

37. Heart treatment method according to claim 36, wherein said predetermined amount is a function of a heartbeat interval at a normal time or of a heart rate at a normal time.

38. Heart treatment method according to claim 37, wherein said function is a predetermined ratio of a heartbeat interval at a normal time or of a heart rate at a normal time.