Claims
- 1. A method of discriminating between captured and loss-of-captured heartbeats, comprising the steps of:
- (a) stimulating a patients heart with a pulse generator;
- (b) monitoring a plurality of segments of a cardiac impedance signal, each segment corresponding to one of a plurality of heartbeats occurring over a time interval corresponding to at least one of said patient's respiratory cycles;
- (c) measuring a peak-to-peak value for each monitored impedance signal segment;
- (d) computing a minimum peak-to-peak value for said plurality of impedance signal segments;
- (e) storing a threshold value corresponding to said minimum peak-to-peak value;
- (f) determining a direction value for each of said monitored impedance signal segments;
- (g) repeating steps (a) through (f) if all of said direction values determined in step (f) are not equal to a common direction;
- (h) monitoring a new plurality of segments of said cardiac impedance signal, each segment corresponding to a new plurality of heartbeats;
- (i) comparing a direction value for each of said new plurality of segments with said common direction;
- (j) for each one comparison performed in step (i), generating a loss-of-capture signal if said one comparison indicates that said direction for said one of said new plurality of segments is not said common direction;
- (k) for each of said new plurality of segments, comparing a peak-to-peak value therefor to said threshold value stored in step (e);
- (l) for each one comparison performed in step (k), generating a loss-of-capture signal if said one comparison indicates that said peak-to-peak value for said one of said plurality of segments is less than said threshold value;
- (m) for each one comparison performed in step (k), generating a capture signal if said one comparison indicates that said peak-to-peak value for said one of said plurality of segments is less than said threshold value.
- 2. A method in accordance with claim 1 above, further comprising the steps of:
- (n) sensing atrial electrical signals occurring during each of said new plurality of impedance signal segments; and
- (o) generating a atrial capture detected signal in response to a predetermined set of conditions relating to said capture signal, said loss-of-capture signals, and said atrial electrical signals.
- 3. A method in accordance with claim 1 above, further comprising the steps of:
- (n) sensing ventricular electrical signals occurring during each of said new plurality of impedance signal segments; and
- (o) generating a ventricular capture detected signal in response to a predetermined set of conditions relating to said capture signal, said loss-of-capture signals, and said ventricular electrical signals.
Parent Case Info
This application is a division of application Ser. No. 346,815 filed 30 Nov. 1994, now U.S. Pat. No. 5,713,933.
US Referenced Citations (21)
Divisions (1)
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Number |
Date |
Country |
Parent |
346815 |
Nov 1994 |
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