DETECTING ELECTRICAL CONDUCTION ABNORMALITIES IN A HEART

• US 20100286541A1
• Filed: 05/11/2009
• Published: 11/11/2010
• Est. Priority Date: 05/11/2009
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Splett, Vincent E., Musley, Shailesh Kumar V., Sambelashvili, Aleksandre T.
• Granted Patent: US 8,391,964 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

Techniques are described for detecting conduction abnormalities in a heart of a patient. In particular, an IMD may be configured to obtain electrical signals corresponding to cardiac activity of the heart of the patient and periodically analyze a most recent electrical signal of the obtained electrical signals to detect an electrical conduction abnormality of the heart. The IMD adjusts a frequency at which the most recent electrical signal is analyzed based on at least one physiological parameter of the patient. For example, the IMD may increase the frequency at which the most recent electrical signal is analyzed when a heart rate parameter has significantly changed and the number of detected premature ventricular contractions (PVCs) is greater than or equal to a threshold number. In this manner, the most recent electrical signal is analyzed at a higher frequency in situations in which conduction abnormalities are more likely.

Claims

1. An implantable medical device (IMD) comprising:

a sensing module configured to acquire cardiac electrical signals corresponding to cardiac activity of a heart of a patient via at least one sensor; and

a processor configured to obtain the cardiac electrical signals corresponding to cardiac activity of a heart of a patient, periodically analyze a most recent cardiac electrical signal of the obtained cardiac electrical signals to monitor for an electrical conduction abnormality of the heart and adjust a frequency at which the most recent electrical signal is analyzed based on at least one physiological parameter of the patient.

2. The IMD of claim 1, wherein the processor adjusts a frequency at which the most recent electrical signal is analyzed based on at least a heart rate parameter of the patient and a number of premature ventricular contractions (PVCs).

3. The IMD of claim 2, wherein the heart rate parameter is a heart rate and the processor increases the frequency at which the most recent electrical signal is analyzed when the heart rate of the patient is greater than a heart rate threshold and a number of PVCs detected is greater than a PVC threshold number.

4. The IMD of claim 3, wherein the processor decreases the frequency at which the most recent electrical signal is analyzed when the heart rate falls below a second threshold heart rate.

5. The IMD of claim 2, wherein the processor increases the frequency at which the most recent electrical signal is analyzed to a first increased frequency when a heart rate parameter has changed by a threshold amount and further increases the frequency at which the most recent electrical signal is analyzed to a second increased frequency when the number of detected premature ventricular contractions (PVCs) is greater than a threshold number.

6. The IMD of claim 2, wherein the heart rate parameter comprises one of a change in heart rate variability and a relative change in a heart rate.

7. The IMD of claim 1, wherein the processor determines whether one or more characteristics of the most recent electrical signal have significantly changed relative to a template electrical signal.

8. The IMD of claim 7, wherein the processor analyzes one of an ST segment of the electrical signal, a T-wave segment of the electrical signal and a QRS segment of the electrical signal.

9. The IMD of claim 1, wherein the processor periodically analyzes a most recent cardiac electrical signal by comparing an EGM corresponding with a most recent beat to a template EGM corresponding to a beat during a normal sinus rhythm using a wavelet transform analysis.

10. The IMD of claim 1, wherein the electrical conduction abnormality is associated with at least one of a cardiac ischemia, a cardiac infarction, a branch bundle block, or fascicular block.

11. A method comprising:

obtaining electrical signals corresponding to cardiac activity of a heart of a patient;

periodically analyzing a most recent electrical signal of the obtained electrical signals to monitor for an electrical conduction abnormality of the heart; and

adjusting a frequency at which the most recent electrical signal is analyzed based on at least one physiological parameter of the patient.

12. The method of claim 11, wherein adjusting the frequency at which the most recent electrical signal is analyzed comprises adjusting the frequency at which the most recent electrical signal is analyzed based on at least a heart rate parameter of the patient and a number of premature ventricular contractions (PVCs).

13. The method of claim 12, wherein the heart rate parameter is a heart rate and adjusting the frequency at which the most recent electrical signal is analyzed comprises increasing the frequency at which the most recent electrical signal is analyzed when the heart rate of the patient is greater than a threshold heart rate and a number of PVCs detected is greater than a threshold number.

14. The method of claim 13, further comprising decreasing the frequency at which the most recent electrical signal is analyzed when the heart rate falls below a second threshold heart rate.

15. The method of claim 12, wherein adjusting the frequency at which the most recent electrical signal is analyzed comprises:

increasing the frequency at which the most recent electrical signal is analyzed to a first increased frequency when the heart rate parameter has changed by a threshold amount; and

further increasing the frequency at which the most recent electrical signal is analyzed to a second increased frequency when the number of detected premature ventricular contractions (PVCs) is greater than a threshold number.

16. The method of claim 11, wherein analyzing the most recent electrical signal of the heart comprises determining whether one or more characteristics of the most recent electrical signal have significantly changed relative to a template electrical signal.

17. The method of claim 16, wherein analyzing the most recent electrical signal of the heart comprises analyzing one of an ST segment of the electrical signal, a T-wave segment of the electrical signal and a QRS segment of the electrical signal.

18. The method of claim 11, wherein the electrical conduction abnormality is associated with at least one of a cardiac ischemia, a cardiac infarction, a branch bundle block, or a fascicular block.

19. The method of claim 11, further comprising performing one of a therapy delivery, a patient notification, an event log in memory and a transmission of a communication in response to detecting the electrical conduction abnormality.

20. The method of claim 11, wherein periodically analyzing a most recent cardiac electrical signal comprises comparing an EGM corresponding with a most recent beat to a template EGM corresponding to a beat during a normal sinus rhythm using a wavelet transform analysis.

21. An implantable medical device (IMD) comprising:

means for obtaining electrical signals corresponding to cardiac activity of a heart of a patient;

means for periodically analyzing a most recent electrical signal of the obtained electrical signals to monitor for an electrical conduction abnormality of the heart; and

means for adjusting a frequency at which the most recent electrical signal is analyzed based on at least one condition of the patient.

22. The device of claim 21, wherein the adjusting means adjusts the frequency at which the most recent electrical signal is analyzed based on at least a heart rate parameter of the patient and a number of premature ventricular contractions (PVCs).

23. The device of claim 22, wherein the heart rate parameter is a heart rate and the adjusting means increases the frequency at which the most recent electrical signal is analyzed when the heart rate of the patient is greater than a threshold heart rate and a number of PVCs detected is greater than a threshold number.

24. The device of claim 23, wherein the adjusting means further decreases the frequency at which the most recent electrical signal is analyzed when the heart rate falls below a second threshold heart rate.