Pulse pressure variability

1. A system, comprising:

a first ambulatory medical device (AMD) comprising an implantable cardiac monitor (ICM) configured to detect physiologic information from a patient and to determine an initial atrial fibrillation (AF) indication using the detected physiologic information;

a second AMD comprising a wearable medical device, different than the first AMD, configured to detect pulse pressure information from the patient; and

an AF circuit configured to confirm the determined initial AF indication using pulse pressure information from the second AMD,

wherein the AF circuit is configured to:

receive physiologic information from N beats of the patient, the physiologic information comprising heart rate (HR) information of the N beats;

receive pulse pressure information of the N beats of the patient; and

sort the N beats based on HR into at least two groups comprising:

a high HR group comprising one or more of the N beats having a relative high HR with respect to the N beats; and

a low HR group comprising one or more of the N beats having a relative low HR with respect to the N beats; and

determine a difference between pulse pressure information from the high HR group and pulse pressure information from the low HR group, and

wherein the AF circuit is configured to confirm the determined initial AF indication using the determined difference between pulse pressure information from the high HR group and pulse pressure information from the low HR group.

2. The system of claim 1 , wherein the wearable medical device includes at least one of a wrist-worn medical device or a finger-worn medical device configured to detect a photoplethysmogram (PPG) signal from the patient.

3. The system of claim 1 , wherein the first AMD is configured to detect at least one of electrocardiogram (ECG) information or heart sound (HS) information from the patient, and to determine the initial AF indication using the detected ECG information, the detected HS information, or the detected ECG and HS information.

4. The system of claim 1 , wherein the first AMD is configured to determine the initial AF indication using the received physiologic information and a threshold, and

wherein the AF circuit is configured to adjust the threshold using the received pulse pressure information.

5. The system of claim 1 , wherein the first AMD comprises the AF circuit.

6. A system, comprising:

an atrial fibrillation (AF) circuit configured to receive physiologic information of a patient from a first ambulatory medical device (AMD); and

a signal receiver circuit configured to receive pulse pressure information of the patient from a second AMD, different than the first AMD, the received pulse pressure information different than the received physiologic information,

wherein the AF circuit is configured to determine a change in the received pulse pressure information and to determine an AF indication using the determined change in the received pulse pressure information with respect to the received physiologic information,

wherein the AF circuit is configured to receive physiologic information from N beats of the patient, the physiologic information comprising heart rate (HR) information of the N beats,

wherein the signal receiver circuit is configured to receive pulse pressure information of the N beats of the patient,

wherein the AF circuit is configured to sort the N beats based on HR into at least two groups comprising:

a high HR group comprising one or more of the N beats having a relative high HR with respect to the N beats; and

a low HR group comprising one or more of the N beats having a relative low HR with respect to the N beats,

wherein, to determine the change in the received pulse pressure information, the AF circuit is configured to determine a difference between pulse pressure information from the high HR group and pulse pressure information from the low HR group, and

wherein the AF circuit is configured to determine the AF indication using the determined difference.

7. The medical device of claim 6 , wherein the AF circuit is configured to determine the AF indication using the received physiologic information, and to confirm the determined AF indication using the received pulse pressure information.

8. The medical device of claim 6 , wherein the AF circuit is configured to determine the AF indication using the received physiologic information and a threshold, and

wherein the AF circuit is configured to adjust the threshold using the received pulse pressure information.

9. The system of claim 6 , comprising the first AMD and the second AMD,

wherein the first AMD comprises an implantable cardiac monitor (ICM) configured to detect physiologic information from the patient, and

wherein the second AMD comprises a wearable medical device configured to detect pulse pressure information from the patient.

10. The system of claim 9 , wherein the first AMD comprises the AF circuit.

11. A method, comprising:

receiving, using an atrial fibrillation (AF) circuit, physiologic information of a patient from a first ambulatory medical device (AMD);

receiving, using a signal receiver circuit, pulse pressure information of the patient from a second AMD, different than the first AMD, the received pulse pressure information different than the received physiologic information; and

determining, using the AF circuit, an initial AF indication using the received physiologic information; and

confirming, using the AF circuit, the determined initial AF indication using the received pulse pressure information,

wherein receiving physiologic information of the patient comprises receiving physiologic information from N beats of the patient, the physiologic information comprising heart rate (HR) information of the N beats,

wherein receiving pulse pressure information of the patient comprises receiving pulse pressure information of the N beats of the patient,

wherein confirming the determined initial AF indication using the received pulse pressure information comprises:

sorting the N beats based on HR into at least two groups comprising:

a high HR group comprising one or more of the N beats having a relative high HR with respect to the N beats; and

a low HR group comprising one or more of the N beats having a relative low HR with respect to the N beats; and

determining a difference between pulse pressure information from the high HR group and pulse pressure information from the low HR group,

wherein confirming the determined initial AF indication comprises using the determined difference between pulse pressure information from the high HR group and pulse pressure information from the low HR group.

12. The method of claim 11 , wherein the first AMD includes an implantable cardiac monitor (ICM), and the second AMD includes a wearable medical device,

wherein the wearable medical device includes at least one of a wrist-worn medical device or a finger-worn medical device configured to detect a photoplethysmogram (PPG) signal from the patient.

13. The method of claim 11 , wherein receiving physiologic information includes receiving at least one of electrocardiogram (ECG) information or heart sound (HS) information from the patient using the first AMD, and

wherein determining the initial AF indication using the received physiologic information includes using the detected ECG information, the detected HS information, or the detected ECG and HS information.

14. The method of claim 11 , wherein determining the initial AF indication comprises using the received physiologic information and a threshold, the method further comprising:

adjusting, using the AF circuit, the threshold using the received pulse pressure information.