US5284491A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cardiac pacemaker with hysteresis behavior
Assignee: Medtronic Inc
•
Filing: 1992-02-27
•
Granted: 1994-02-08
•
Expires: 2012-02-27
Abstract
Abstract A pacemaker having a hysteresis feature which permits intrinsic heart activity, controlled by the sinus node to resume optimally after pacing. The pacemaker has a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable rate (IR) intermediate an upper pacing rate (UR) and a lower pacing rate (LR). A microprocessor measures the average rate of change MAVG in the intervals between consecutive ventricular depolarizations, and compares the last intrinsic escape interval RRN to the lower rate hysteresis interval (LRHI). If the last intrinsic escape interval RRN is longer than the lower rate hysteresis interval (LRHI), and if the value of MAVG is greater than a first preselected value SL1 but less than a second preselected value SL2, the pacemaker stimulates at the lower rate hysteresis (LRH) and thereafter gradually increases the pacing rate up to the intermediate rate (IR). A time counter maintains a continuous pacing at the intermediate rate (IR) for a predefined period of time, and the pacing rate is gradually decreased toward the lower pacing rate (LR).
Inventors
- 👤 Richard Sutton
- 👤 Ivan Bourgeois
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:55
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/365
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
136 words
In a pacemaker having a programmable lower rate and upper rate, a programmable lower rate hysteresis (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable intermediate pacing rate (IR) the improvement comprising: A. means for measuring rate of change M AVG of successive cardiac intrinsic escape intervals; B. means for comparing M AVG to a first predefined limit SL 1 ; C. means for comparing the last intrinsic escape interval to the lower rate hysteresis interval (LRHI); and D. means for stimulating a heart at the lower rate hysteresis (LRH) and for gradually incrementing a pacing rate until the pacing ratio reaches the intermediate pacing rate (IR) if the last intrinsic escape interval is longer than the lower rate hysteresis interval (LRHI) and if said M AVG is greater than SL 1 .
Claim 2
Dependent Claim
136 words
In a pacemaker having a programmable lower rate and upper rate, a programmable lower rate hysteresis (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable intermediate pacing rate (IR) the improvement comprising: A. means for measuring rate of change M AVG of successive cardiac intrinsic escape intervals; B. means for comparing M AVG to a first predefined limit SL 1 ; C. means for comparing the last intrinsic escape interval to the lower rate hysteresis interval (LRHI); and D. means for stimulating a heart at the lower rate hysteresis (LRH) and for gradually incrementing a pacing rate until the pacing ratio reaches the intermediate pacing rate (IR) if the last intrinsic escape interval is longer than the lower rate hysteresis interval (LRHI) and if said M AVG is greater than SL 1 .
Claim 3
Dependent Claim
46 words
The pacemaker according to claim 1 further comprising: A. time counter means for maintaining continuous pacing at the intermediate rate (IR) for a predefined period of time; and B. means for allowing gradual decay of the pacing rate after said selected period of time has lapsed.
Claim 4
Dependent Claim
17 words
The pacemaker according to claim 2, wherein said selected programmable time is set equal to five minutes.
Claim 5
Dependent Claim
46 words
The pacemaker according to claim 1, wherein said means for measuring the rate of change M AVG comprising: A. means for measuring intervals between two successive ventricular depolarizations (RR intervals); and B. means for averaging the rate of change M AVG of said successive RR intervals.
Claim 6
Dependent Claim
89 words
The pacemaker according to claim 4, wherein said means for averaging the rate of change of said RR intervals comprises: A. means for calculating a difference D between two successive RR intervals; B. means for comparing said difference D to a predetermined reference value; C. means for storing those values of D which are greater than said reference value; D. means for calculating a sum M of N stored values of D, wherein N is a predetermined positive integer; and E. means for setting M AVG equal to M/N.
Claim 7
Dependent Claim
32 words
The pacemaker according to claim 5, wherein said means for averaging M AVG comprising means for averaging the values of D greater than said reference value over a predefined period of time.
Claim 8
Dependent Claim
23 words
The pacemaker according to claim 6, wherein said reference value is zero, and wherein only positive values of D are stored and added.
Claim 9
Dependent Claim
14 words
The pacemaker according to claim 5, wherein N is set equal to six beats.
Claim 10
Dependent Claim
33 words
The pacemaker according to claim 4, further including means for comparing M AVG to a second predetermined limit SL 2 wherein SL 2 has a value greater than that of SL 1 .
Claim 11
Dependent Claim
59 words
The pacemaker according to claim 9, wherein said means for stimulating gradually increments the pacing rate until the pacing rate reaches the intermediate pacing rate (IR), if the last intrinsic escape interval RR N is longer than LRHI, and if M AVG is greater than or equal to SL 1 but less than or equal to SL 2 .
Claim 12
Dependent Claim
34 words
The pacemaker according to claim 9, further comprising means for inhibiting stimulation if M AVG is greater than SL 2 , and if the RR N interval is less than or equal to LRHI.
Claim 13
Dependent Claim
34 words
The pacemaker according to claim 11, further comprising means for stimulating at the lower rate if M AVG is greater than SL 2 , and if the RRN interval will be longer than LRHI.
Claim 14
Dependent Claim
64 words
The pacemaker according to claim 11, further comprising: A. means for inhibiting stimulation if M AVG is greater than SL 2 , and if the RR N interval is less than or equal to LRH; and B. means for stimulating at the lower rate if M AVG is greater than SL 2 , and if the RR N interval will be longer than LRHI.
Claim 15
Dependent Claim
37 words
The pacemaker according to claim 4, further including means for inhibiting stimulation if M AVG is less than SL 1 , and if the last intrinsic escape interval RR N is less than or equal to LRHI.
Claim 16
Dependent Claim
35 words
The pacemaker according to claim 14, further comprising means for stimulating at the lower rate if M AVG is less than SL 1 , and if the RR N interval will be greater than LRHI.
Claim 17
Independent Claim
134 words
A method for pacing with a pacemaker having a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable intermediate pacing rate (IR), the pacing method comprising the steps of: A. measuring a rate of change of M AVG of successive intrinsic escape intervals; B. comparing M AVG to a first predetermined limit SL 1 ; C. comparing a last intrinsic escape interval RR N to the lower rate hysteresis interval (LRHI); and D. stimulating at the lower rate hysteresis (LRH) and gradually incrementing a pacing rate until it reaches the intermediate pacing rate (IR) if the RR N interval will be longer than the lower rate hysteresis interval (LRHI) and if said M AVG is greater than SL 1 .
Claim 18
Independent Claim
134 words
A method for pacing with a pacemaker having a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable intermediate pacing rate (IR), the pacing method comprising the steps of: A. measuring a rate of change of M AVG of successive intrinsic escape intervals; B. comparing M AVG to a first predetermined limit SL 1 ; C. comparing a last intrinsic escape interval RR N to the lower rate hysteresis interval (LRHI); and D. stimulating at the lower rate hysteresis (LRH) and gradually incrementing a pacing rate until it reaches the intermediate pacing rate (IR) if the RR N interval will be longer than the lower rate hysteresis interval (LRHI) and if said M AVG is greater than SL 1 .
Claim 19
Dependent Claim
44 words
The pacing method according to claim 16 further comprising the steps of: A. maintaining continuous pacing at the intermediate rate (IR) for a predefined period of time; and B. allowing gradual decay of the pacing rate after said selected period of time has lapsed.
Claim 20
Dependent Claim
43 words
The pacing method according to claim 17, wherein, said step of measuring the rate of change M AVG comprises: A. measuring intervals between two successive ventricular depolarizations (RR intervals); and B. averaging the rate of change M AVG of said successive RR intervals;
Claim 21
Dependent Claim
80 words
The pacing method according to claim 18, wherein said step of averaging the rate of change of said RR intervals comprises: A. calculating a difference D between two successive RR intervals; B. comparing the difference D to a predetermined reference value; C. storing those values of D which are greater than said reference value; D. calculating a sum M of N stored values of D, wherein N is a predetermined positive integer; and E. setting M AVG equal to M/N.
Claim 22
Dependent Claim
35 words
The pacing method according to claim 19, further comprising the step comparing M AVG to a second predetermined limit SL 2 , wherein SL 2 has a value greater than that of SL 1 .
Claim 23
Dependent Claim
56 words
The pacing method according to claim 20, wherein said step of stimulating comprises gradually incrementing the pacing rate until it reaches the intermediate pacing rate (IR), if the RRN interval will be longer than LRHI, and if M AVG is greater than or equal to SL 1 but less than or equal to SL 2 .
Claim 24
Dependent Claim
125 words
The pacing method according to claim 18, further comprises: A. the step of inhibiting stimulation if M AVG is less than SL 1 , and if the last sensed RR interval is less than or equal to LRHI; B. the step of stimulating at the lower rate if M AVG is less than SL 1 , and if the RR N interval will be longer than LRHI; C. the step of inhibiting stimulation if M AVG is greater than SL 2 , and if the RR N interval is less than or equal to LRHI; and D. the step of stimulating at the lower rate if M AVG is greater than SL 2 , and if the RR N interval will be longer than LRHI.
References Cited (Backward Citations)
US3661157A
Cited
US3857399A
Cited
US3921642A
Cited
US4169480A
Cited
US4363325A
Cited
US4856523A
Cited
US4972834A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-07 | 1997-08-09 | 1998-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-07 | 2001-08-09 | 2002-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-07 | 2005-08-09 | 2006-02-08 | $7700.00 | Window Closed / Lapsed |