Atrial fibrillation detection
Embodiments of a wearable monitoring device system can include one or more dry ECG electrodes and a processor that can be configured with one or more algorithms for detecting atrial fibrillation (AF) from sensed ECG signals sensed by the one or more dry ECG electrodes, and optionally other signals. In some embodiments the algorithms include one or more AF detection algorithms and optionally a noise detection algorithm. In some embodiments the wearable monitoring device or a remote system that receives data from the wearable medical device may calculate and/or characterize AF burden from ECG signals sensed by the one or more dry ECG electrodes.
1. A wearable medical device (WMD) system for detecting atrial fibrillation (AF) in a patient capable of being ambulatory while using the WMD system, the WMD system comprising:
a plurality of electrocardiogram (ECG) electrodes configured to sense a multichannel ECG signal while the patient is using the WMD system;
a support structure configured to position at least one of the plurality of ECG electrodes to contact a body of the patient while the support structure is worn by the patient;
one or more processors, communicatively coupled to the plurality of ECG electrodes, configured with:
a first AF detection module configured to analyze the multichannel ECG signal using a first algorithm and output first information, and
a second AF detection module configured to analyze the multichannel ECG signal using a second algorithm with a different noise tolerance from the first algorithm and output second information,
wherein, based at least in part on the first information and the second information, the one or more processors determine whether the multichannel ECG signal is indicative of AF; and
a communication module, communicatively coupled to the one or more processors, configured to:
responsive to a determination that the multichannel ECG signal is indicative of AF, provide a notification that the AF has been detected.
2. The WMD system of claim 1 , wherein the one or more processors are further configured with a noise detection module configured to analyze the multichannel ECG signal and output third information, and wherein the one or more processors determine whether the multichannel ECG signal is indicative of AF, based at least in part on the first information, the second information, and the third information.
3. The WMD system of claim 2 , wherein responsive to the third information provided by the noise detection module, the one or more processors determine whether the multichannel ECG signal is indicative of noise.
4. The WMD system of claim 3 , wherein the one or more processors analyze a plurality of multichannel ECG signals over a predetermined time period and determine AF burden over the predetermined time period without using ECG signals of the plurality of multichannel ECG signals that are determined to be indicative of noise.
5. The WMD system of claim 3 , wherein the one or more processors analyze a plurality of multichannel ECG signals over a predetermined time period and characterize AF burden over the predetermined time period by providing a metric corresponding to an amount of time during the predetermined time period in which one or more ECG signals of the plurality of multichannel ECG signals were determined to be indicative of noise.
6. The WMD system of claim 3 , wherein the one or more processors analyze a plurality of multichannel ECG signals over a predetermined time period and characterize AF burden over the predetermined time period by providing a metric corresponding to a first amount of time during the predetermined time period in which one or more ECG signals of the plurality of multichannel ECG signals were determined to be indicative of detected AF, and a metric corresponding to a second amount of time during the predetermined time period in which one or more ECG signals of the plurality of multichannel ECG signals were determined to be indicative of suspected AF.
7. The WMD system of claim 6 , wherein the first algorithm determines the detected AF and the second algorithm determines the suspected AF.
8. The WMD system of claim 2 , wherein the third information provided by the noise detection module includes information indicating one or more channels of the multichannel ECG signal meeting a noise criterion, and one or more channels of the multichannel ECG signal not meeting the noise criteria, and wherein the one or more processors use the first AF detection module to analyze the one or more channels that meet the noise criterion and the second AF detection module to analyze the one or more channels that do not meet the noise criterion.
9. The WMD system of claim 1 , wherein the one or more processors analyze a plurality of multichannel ECG signals over a predetermined time period and determine AF burden over the predetermined time period.
10. The WMD system of claim 1 , wherein the first algorithm comprises a high specificity AF algorithm and the second algorithm comprises a noise-tolerant AF algorithm with less specificity than the first algorithm.
11. The WMD system of claim 1 , wherein the WMD comprises an external defibrillator.
12. A wearable medical device (WMD) system for detecting atrial fibrillation (AF) in a patient capable of being ambulatory while using the WMD system, the WMD system comprising:
a plurality of electrocardiogram (ECG) electrodes configured to sense a multichannel ECG signal while the patient is using the WMD system;
a support structure configured to position at least one of the plurality of ECG electrodes to contact a body of the patient while the support structure is worn by the patient;
an AF detector, communicatively coupled to at least the plurality of ECG electrodes, configured to:
analyze, using a first algorithm, the multichannel ECG signal, wherein the first algorithm outputs first information,
analyze, using a second algorithm, the multichannel ECG signal, wherein the second algorithm has a different noise tolerance from the first algorithm and outputs second information,
determine whether the multichannel ECG signal is indicative of AF based at least in part on the first information and the second information, and
determine whether the multichannel ECG signal is indicative of suspected AF based at least in part on the first information and the second information; and
a communication module, communicatively coupled to at least the AF detector, configured to:
responsive to a determination that the multichannel ECG signal is indicative of AF, provide a notification that the AF has been detected, and
responsive to a determination that the multichannel ECG signal is indicative of suspected AF, provide a notification that the suspected AF has been detected.
13. The WMD system of claim 12 , wherein the AF detector is configured to analyze the multichannel ECG signal further using a noise detection algorithm, wherein the noise detection algorithm outputs noise analysis information, and wherein the AF detector is configured to determine whether the multichannel ECG signal is indicative of AF further based on the noise analysis information.
14. The WMD system of claim 13 , wherein the noise analysis information includes information indicating one or more channels of the multichannel ECG signal that exceeded a noise criterion and one or more channels of the multichannel ECG signal that did not exceed the noise criterion.
15. The WMD system of claim 14 , wherein the one or more channels that exceeded the noise criterion are analyzed using the first algorithm, and the one or more channels that did not exceed the noise criterion are analyzed using the second algorithm.
16. The WMD system of claim 14 , wherein the AF detector is further configured to determine an AF burden over a predetermined time period without using the one or more channels of the multichannel ECG signal that exceeded the noise criterion.
17. The WMD system of claim 14 , wherein the AF detector is further configured to:
determine a metric corresponding to a first amount of time over a predetermined time period in which the multichannel ECG signal was determined to be indicative of the detected AF, and
determine another metric corresponding to a second amount of time over the predetermined time period in which the multichannel ECG signal was determined to be indicative of the suspected AF.
18. The WMD system of claim 12 , wherein in response to a determination that the multichannel ECG signal is indicative of AF, the AF detector is further configured to determine an AF burden over a predetermined time period.
19. The WMD system of claim 12 , wherein the first algorithm is used to determine the detected AF and the second algorithm is used to determine the suspected AF.
20. The WMD system of claim 12 , wherein the first algorithm comprises a high specificity AF algorithm and the second algorithm comprises a noise-tolerant AF algorithm with less specificity than the first algorithm.