System for cardiac medical condition detection and characterization
A system and method provides monitoring for atrial fibrillation. A data acquisition processor acquires a cardiac signal data stream from a patient and a wave detector detects an R-wave in a cardiac signal of the data stream. A T-wave in the cardiac signal occurring after the detected R-wave and a Q-wave in a subsequent cardiac signal of the data stream is also detected by the wave detector. A filter provides signal gating and extraction of data representing a Region of Interest (ROI) time window from the detected T-wave to the Q-wave. An integration processor detects characteristics of a P wave signal occurring within the ROI time window. At least one of the detected P wave characteristics is compared to characteristics derived from data representing at least one P wave signal and generating an output signal in response to the comparison for use in determining if the patient is in atrial fibrillation.
1. A system for monitoring atrial fibrillation comprising:
a data acquisition processor for acquiring a cardiac signal data stream from a patient;
a wave detector for detecting an R-wave in a cardiac signal of the data stream, said wave detector detecting a T-wave in the cardiac signal occurring after the detected R-wave and a Q point in a successive subsequent cardiac signal of the data stream;
a filter for signal gating and extraction of data representing a Region of Interest (ROI) time window from substantially the end of the detected T-wave to the detected successive subsequent Q point;
an integration processor for detecting characteristics of a P wave signal occurring within the ROI time window, comparing a latency of the P wave comprising a time duration within the ROI time window that the P wave occurs relative to both the T-wave and the Q-wave within the ROT time window, to corresponding characteristics derived from data representing at least one P wave signal and generating an output signal in response to the comparison for use in determining if the patient is in atrial fibrillation.
2. The system as claimed in claim 1 , wherein the detected characteristics include an amplitude of the P wave and an entropy of the cardiac signal.
3. The system of claim 2 , wherein the entropy of the cardiac signal is determined according to:
H
(
P
)
=
-
∑
s
∈
S
P
(
s
)
·
log
P
(
s
)
wherein s is the ROI window.
4. The system of claim 2 , further comprising a processor for performing Max-min analysis; multi-beat averaging; and heart rate variability (HRV) and RR interval analysis.
5. The system of claim 4 , wherein said integration processor generates the output signal in response to any combination of detecting the entropy of the cardiac signal within the T-Q window; Max-min analysis; multi-beat averaging; and heart rate variability (HRV) and RR interval analysis.
6. The system of claim 1 , further including a repository for storing a plurality of data sets from which the data representing at least one P wave signal is selected.
7. The system of claim 6 , wherein the data of each of the plurality of data sets represent at least one P wave signal associated with a respective physiological characteristic.
8. The system of claim 7 , wherein the associated physiological characteristics include at least one of age, weight, gender, sex and ethnicity.
9. The system of claim 1 , further comprising a transmitter for automatically transmitting the output signal to a remote unit for viewing and analysis by a user.
10. The system of claim 1 , further comprising a buffer for recording the output signal generated by the integration processor.
11. The system of claim 1 , further comprising an alarm for notifying a user in response to a determination the patient is in atrial fibrillation.
12. The system of claim 11 , wherein said alarm receives the output signal from said integration processor and generates at least one of an audible and visual alarm in response to a determination the patient is in atrial fibrillation.
13. A method for detecting atrial fibrillation, said method comprising the activities of:
acquiring a cardiac signal data stream;
detecting an R-wave in a cardiac signal of the cardiac signal data stream;
detecting a T-wave in the cardiac signal and a Q point in a successive subsequent cardiac signal of the data stream;
filtering the cardiac signal to obtain a T-Q window from substantially the end of the detected T-wave to the detected successive subsequent Q point;
detecting characteristics of a P wave within the T-Q window; and
comparing the detected P wave characteristics including a latency of the P wave comprising a time duration within the T-Q time window that the P wave occurs relative to both the T-wave and the Q-wave within the T-Q time window, to a threshold value; and
determining if a patient is in atrial fibrillation in response to the comparison.
14. The method as claimed in claim 13 , wherein the activity of detecting characteristics includes determining an amplitude of the P wave and an entropy of the cardiac signal within the T-Q window.
15. The method as claimed in claim 13 , wherein said activity of determining entropy is performed according to:
H
(
P
)
=
-
∑
s
∈
S
P
(
s
)
·
log
P
(
s
)
wherein s is the ROI window.
16. The method as claimed in claim 13 , further comprising the activity of transmitting the output signal to a remote unit for viewing and analysis by a user.
17. The method as claimed in claim 13 , further comprising the activity of recording the output signal generated by the integration processor.
18. The method as claimed in claim 13 , further comprising the activity of determining the patient is in atrial fibrillation in response to the comparison and notifying a user.
19. The method as claimed in claim 13 , further comprising the activities of:
performing at least one of Max-min analysis, multi-beat averaging and heart rate variability (HRV) and RR interval analysis; and
determining if atrial fibrillation has occurred in response to both said activities of comparing and performing.
20. A method for detecting atrial fibrillation, said method comprising the activities of:
acquiring a cardiac signal data stream;
detecting an R-wave in a cardiac signal of the cardiac signal data stream;
detecting a T-wave in the cardiac signal and a Q point in a successive subsequent cardiac signal of the data stream;
filtering the cardiac signal to obtain a T-Q window from substantially the end of the detected T-wave to the detected successive subsequent Q point;
detecting characteristics of a P wave within the T-Q window; and
comparing the detected P wave characteristics including a latency of the P wave comprising a time duration within the T-Q time window that the P wave occurs relative to both the T-wave and the Q-wave within the T-Q time window, to a threshold value; and
determining if a patient is in atrial fibrillation in response to the comparison.
21. The method as claimed in claim 20 , further comprising the activities of:
comparing the detected P wave characteristics including an amplitude of the P wave, to said threshold value.