Distributed cardiac activity monitoring with selective filtering
View Patent ↗System and techniques for distributed monitoring of cardiac activity include selective T wave filtering. In general, in one implementation, a distributed cardiac activity monitoring system includes a monitoring apparatus, with a selectively activated T wave filter, and a monitoring station. The monitoring apparatus can include a communications interface, a real-time QRS detector, a T wave filter, and a selector that activates the T wave filter to preprocess a cardiac signal provided to the real-time QRS detector in response to a message. The monitoring station can communicatively couple with the monitoring apparatus, over a communications channel, via the communications interface and can transmit the message to the monitoring apparatus to activate the T wave filter based at least in part upon a predetermined criteria (e.g., abnormal T waves for an individual, as identified by a system operator).
1. A machine-implemented method comprising:
identifying heart beats in a sensed cardiac signal;
activating a T wave filter frequency domain, used in said identifying heart beats, in response to a message from a monitoring station generated at least in part based upon discovery of a predetermined characteristic in the sensed cardiac signal; and
outputting information corresponding to the identified heart beats to a communications channel of a distributed cardiac activity monitoring system.
2. The method of claim 1 , wherein said identifying heart beats comprises identifying R waves in the sensed cardiac signal.
3. The method of claim 1 , further comprising sending at least a portion of the sensed cardiac signal to the monitoring station, and wherein the discovery of the predetermined characteristic comprises identification of a tall T wave in the at least a portion of the sensed cardiac signal by an operator at the monitoring station.
4. The method of claim 1 , wherein said activating the T wave filter frequency domain comprises activating a filter that reduces signal amplitude at low frequencies of the sensed cardiac signal.
5. The method of claim 4 , wherein the filter has a frequency response of about 0 dB or more at frequencies above ten Hertz.
6. The method of claim 5 , wherein the filter has a frequency response of about −10 dB or less in a low frequency range of zero to five Hertz.
7. The method of claim 6 , wherein the filter has a frequency response of about +2 dB or more in a high frequency range of twenty to twenty five Hertz.
8. The method of claim 1 , wherein said outputting information comprises outputting heart rate data to a wireless communications channel.
9. The method of claim 1 , further comprising:
determining that an abnormal T wave is possible based on signal morphology analysis; and
notifying a system operator of the possible abnormal T wave.
10. The method of claim 1 , further comprising deactivating the T wave filter frequency domain in response to a second message.
11. A distributed cardiac activity monitoring system comprising:
a monitoring apparatus including a communications interface, a real-time QRS detector, a T wave filter frequency domain, and a selector that activates the T wave filter with respect to the real-time QRS detector in response to a message, wherein the activated T wave filter frequency domain preprocesses a cardiac signal provided to the real-time QRS detector; and
a monitoring station that communicatively couples with the monitoring apparatus via the communications interface and transmits the message to the monitoring apparatus to activate the T wave filter frequency domain based at least in part upon a predetermined criteria.
12. The system of claim 11 , wherein the communications interface comprises a wireless communications interface.
13. The system of claim 11 , wherein the T wave filter frequency domain comprises a filter that reduces signal amplitude at low frequencies.
14. The system of claim 13 , wherein the filter has a frequency response of about −10 dB or less in a low frequency range of zero to five Hertz.
15. The system of claim 13 , wherein the filter has a frequency response of about 0 dB or more at frequencies above ten Hertz.
16. The system of claim 15 , wherein the filter has a frequency response of about +2 dB or more in a high frequency range of twenty to twenty five Hertz.
17. The system of claim 11 , wherein the selector comprises analog, selective activation circuitry.
18. The system of claim 11 , wherein the monitoring apparatus further comprises additional logic that determines if an abnormal T wave is possible based on signal morphology analysis, and notifies a system operator of the possible abnormal T wave.
19. The system of claim 11 , wherein the monitoring station further comprises additional logic that determines if an abnormal T wave is possible based on signal morphology analysis, and notifies a system operator of the possible abnormal T wave.
20. A cardiac monitoring apparatus comprising:
a communications interface;
a real-time heart beat detector;
a T wave filter frequency domain; and
a selector that activates the T wave filter frequency domain with respect to the real-time heart beat detector in response to a message, wherein the activated T wave filter frequency domain preprocesses a cardiac signal provided to the real-time heart beat detector.
21. The apparatus of claim 20 , wherein the communications interface comprises a wireless communications interface.
22. The apparatus of claim 20 , wherein the real-time heart beat detector comprises an analog heart beat detector, the T wave filter frequency domain comprises an analog T wave filter, and the selector comprises analog, selective activation circuitry.
23. The apparatus of claim 20 , wherein the T wave filter frequency domain comprises a filter that reduces signal amplitude at low frequencies.
24. The apparatus of claim 23 , wherein the filter has a frequency response of about −10 dB or less in a low frequency range of zero to five Hertz.
25. The apparatus of claim 24 , wherein the filter has a frequency response of about 0 dB or more at frequencies above ten Hertz.
26. The apparatus of claim 25 , wherein the filter has a frequency response of about +2 dB or more in a high frequency range of twenty to twenty five Hertz.
27. The apparatus of claim 20 , further comprising additional logic that determines if an abnormal T wave is possible based on signal morphology analysis, and notifies a system operator of the possible abnormal T wave.
28. A method comprising:
receiving at least a portion of a sensed cardiac signal from a monitoring apparatus in contact with a living being under active cardiac monitoring;
identify an abnormal T wave in the received cardiac signal; and
sending a message to the monitoring apparatus over a communications channel, the message causing the monitoring apparatus to activate a T wave filter frequency domain used in identifying heart beats of the living being under active cardiac monitoring.
29. The method of claim 28 , further comprising:
determining that an abnormal T wave is possible based on signal morphology analysis; and
notifying a system operator of the possible abnormal T wave, wherein the system operator performs said identifying the abnormal T wave.
30. The method of claim 28 , wherein said sending the message comprises sending the message over a wireless communications channel.
31. The method of claim 28 , further comprising installing the T wave filter frequency domain into the monitoring apparatus, which comprises a preexisting beat detector.
32. A system comprising:
means for identifying heart beats in a sensed cardiac signal;
means for filtering the sensed cardiac signal to reduce T waves in the sensed cardiac signal; and
means for selectively activating the means for filtering in response to discovery of a predetermined characteristic in the sensed cardiac signal.
33. The system of claim 32 , further comprising means for alerting a system operator of a possible abnormal T wave.
34. The system of claim 32 , wherein the means for filtering comprises means for generally highpass filtering.