Method and apparatus for detecting atrial filling pressure
A cardiac rhythm management system provides for ambulatory monitoring of hemodynamic performance based on quantitative measurements of heart sound related parameters for diagnostic and therapeutic purposes. Monitoring of such heart sound related parameters allows the cardiac rhythm management system to determine a need for delivering a therapy and/or therapy parameter adjustments based on conditions of a heart. This monitoring also allows a physician to observe or assess the hemodynamic performance for diagnosing and making therapeutic decisions. Because the conditions of the heart may fluctuate and may deteriorate significantly between physician visits, the ambulatory monitoring, performed on a continuous or periodic basis, ensures a prompt response by the cardiac rhythm management system that may save a life, prevent hospitalization, or prevent further deterioration of the heart.
1. A system comprising:
an implantable medical device, including:
a heart sound sensor, configured to sense a heart sound signal of a heart;
a heart sound detector, coupled to the heart sound sensor, the heart sound detector configured to detect at least one parameter using the heart sound signal, the at least one parameter including an amplitude and a duration of a heart sound; and
a processor, coupled to the heart sound detector, the processor configured to adjust the duration using the amplitude, and to provide the adjusted duration as a diagnostic indicator;
wherein the processor is configured to use the adjusted duration to distinguish between at least two atrial filling pressure magnitudes.
2. The system of claim 1 , wherein the at least two atrial filling pressure magnitudes includes a high atrial filling pressure, wherein the high atrial filling pressure includes an atrial filling pressure above a threshold.
3. The system of claim 2 , wherein the threshold includes an absolute pressure threshold of 20 mmHg.
4. The system of claim 2 , wherein the threshold includes an absolute pressure threshold of 25 mmHg.
5. The system of claim 2 , wherein the threshold includes a population-based threshold.
6. The system of claim 1 , wherein the at least one parameter includes a measured duration of an S 2 heart sound normalized by a measured amplitude of the same S 2 heart sound.
7. The system of claim 1 , wherein the implantable medical device includes a cardiac sensor, coupled to the heart sound detector, the cardiac sensor configured to sense a cardiac signal of the heart; and
wherein the heart sound detector is configured to detect the at least one parameter using the heart sound signal and the cardiac signal.
8. The system of claim 1 , including:
a posture sensor, coupled to the processor, the posture sensor configured to sense a posture signal; and
wherein the processor is configured to use the posture signal and the adjusted duration as a diagnostic indicator to distinguish between the at least two atrial filling pressure magnitudes.
9. A system comprising:
an implantable medical device, including:
a heart sound sensor, configured to sense a heart sound signal of a heart;
a heart sound detector, coupled to the heart sound sensor, the heart sound detector configured to detect at least one parameter using the heart sound signal, the at least one parameter including a frequency characteristic of a heart sound; and
a processor, coupled to the heart sound detector, the processor configured to use the frequency characteristic as a diagnostic indicator.
10. The system of claim 9 , wherein the processor is configured to use the frequency characteristic to distinguish between at least two atrial filling pressure magnitudes.
11. The system of claim 10 , wherein the at least two atrial filling pressure magnitudes includes a high atrial filling pressure, wherein the high atrial filling pressure includes an atrial filling pressure above a threshold.
12. The system of claim 11 , wherein the threshold includes an absolute pressure threshold of 20 mmHg.
13. The system of claim 11 , wherein the threshold includes an absolute pressure threshold of 25 mmHg.
14. The system of claim 11 , wherein the threshold includes a population-based threshold.
15. The system of claim 9 , wherein the at least one parameter includes a frequency characteristic comprising a fundamental frequency of an S 1 , S 2 , S 3 , or S 4 heart sound.
16. The system of claim 15 , wherein the at least one parameter includes a frequency characteristic comprising a fundamental frequency of an S 3 heart sound.
17. The system of claim 15 , wherein the at least one parameter includes a frequency characteristic comprising a fundamental frequency of an S 4 heart sound.
18. The system of claim 9 , wherein the implantable medical device includes a cardiac sensor, coupled to the heart sound detector, the cardiac sensor configured to sense a cardiac signal of the heart; and
wherein the heart sound detector is configured to detect the at least one parameter using the heart sound signal and the cardiac signal.
19. The system of claim 9 , including:
a posture sensor, coupled to the processor, the posture sensor configured to sense a posture signal; and
wherein the processor is configured to use the posture signal and the at least one parameter comprising a frequency characteristic as a diagnostic indicator to distinguish between the at least two atrial filling pressure magnitudes.
20. A system comprising:
a heart sound sensor, configured to sense a heart sound signal of a heart;
a heart sound detector, coupled to the heart sound sensor, the heart sound detector configured to detect at least one parameter using the heart sound signal, the at least one parameter including an amplitude and a duration of a heart sound; and
a processor, coupled to the heart sound detector, the processor configured to adjust the duration using the amplitude, and to use the adjusted duration to distinguish between at least two atrial filling pressure magnitudes.