Pacing site and configuration optimization using a combination of electrical and mechanical information
An apparatus comprises a cardiac signal sensing circuit configured to sense a plurality of intrinsic cardiac signals using a plurality of cardiac pacing sites, a heart sound sensing circuit, a stimulus circuit configured to provide an electrical cardiac pacing stimulus to the plurality of pacing sites, and a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit. The control circuit includes a pacing site locating circuit configured to generate an indication of a preferred pacing site as one of a) a subset of the respective cardiac pacing sites selected using the intrinsic ventricular activation time interval, from which subset the preferred pacing site is selected using the heart sound characteristic; or b) a subset of the respective cardiac pacing sites selected using the heart sound characteristic, from which subset the preferred pacing site is selected using the ventricular activation time interval.
1. An apparatus for coupling to a plurality of electrodes to be arranged at a plurality of cardiac pacing sites, the apparatus comprising:
a stimulus circuit configured to provide an electrical pacing stimulus to the plurality of pacing sites;
a heart sound sensing circuit including a heart sound sensor, the heart sound sensing circuit configured to produce a heart sound signal representative of mechanical cardiac activity;
a control circuit electrically coupled to the stimulus circuit, wherein the control circuit includes a pacing site locating circuit configured to:
determine an intrinsic S1 heart sound parameter using an intrinsic heart sound signal sensed using the heart sound sensing circuit;
initiate delivery of electrical pacing stimulation to two or more of the plurality of pacing sites;
determine a paced S1 heart sound parameter using a sensed paced heart sound signal for the two or more of the plurality of pacing sites; and
generate an indication of a pacing site for pacing stimulation using a comparison of the intrinsic S1 heart sound parameter and the paced S1 heart sound parameter, and
wherein the control circuit is configured to initiate delivery of the pacing stimulation using the indicated pacing site.
2. The apparatus of claim 1 , wherein the pacing site locating circuit is configured to generate the indication of a pacing site using a difference between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound.
3. The apparatus of claim 2 , wherein the pacing site locating circuit is configured to generate the indication of a pacing site as the pacing site with the largest difference between the amplitude of the paced S1 heart sound and the amplitude of the intrinsic S1 heart sound.
4. The apparatus of claim 1 , including a cardiac signal sensing circuit configured to produce a sensed cardiac signal representative of electrical cardiac activity; wherein the pacing site locating circuit is configured to identify a pacing site as a viable pacing site when a difference between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound satisfies a specified threshold difference; and select the indicated pacing site from identified viable pacing sites using a parameter determined from the sensed cardiac signal.
5. The apparatus of claim 4 , wherein the control circuit includes a signal processing circuit configured to determine a ventricular activation time interval value using the sensed cardiac signal, and wherein the pacing site locating circuit is configured to initiate delivery of an electrical pacing pulse to the plurality of pacing sites; identify a subset of the plurality of pacing sites as the viable pacing sites using the intrinsic S1 heart sound amplitude and the paced S1 heart sound amplitude; and select the indicated pacing site from the subset of viable pacing sites using the ventricular activation time interval value.
6. The apparatus of claim 4 , wherein the pacing site locating circuit is configured to measure a plurality of differences between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound for the plurality of pacing sites and determine the threshold difference from the determined plurality of differences.
7. The apparatus of claim 1 , including a cardiac signal sensing circuit configured to sense a cardiac signal, wherein a cardiac signal is representative of electrical cardiac activity; wherein the control circuit includes a signal processing circuit configured to determine an intrinsic ventricular activation time interval value using the sensed cardiac signal, and wherein the pacing site locating circuit is configured to identify a subset of the plurality of cardiac pacing sites using the intrinsic ventricular activation time interval value, initiate delivery of an electrical pacing pulse to the subset of the cardiac pacing sites, and select the indicated pacing site from the subset of the cardiac pacing sites using the intrinsic S1 heart sound parameter and the paced intrinsic S1 heart sound parameter.
8. The apparatus of claim 7 , wherein the intrinsic ventricular activation time interval value includes one or more of a time interval between a Q-wave and left ventricular activation (Q-LV interval), a time interval between right ventricular activation and left ventricular activation (RV-LV) interval, and a time delay between activation of an atrium and activation of a ventricle (AV delay).
9. The apparatus of claim 1 , including a cardiac signal sensing circuit configured to produce a sensed cardiac signal, wherein a cardiac signal is representative of electrical cardiac activity; wherein the pacing site locator circuit is configured to determine a time interval between an R-wave of the sensed cardiac signal and the intrinsic S1 heart sound (intrinsic R-S1 interval); determine a paced R-S1 interval; and generate the indication of a pacing site using a difference between the intrinsic R-S1 interval and the paced R-S1 interval.
10. The apparatus of claim 1 , wherein the pacing site locating circuit configured to generate the indication of a pacing site using a difference between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound; and generate an indication of a weak responder to electrical pacing therapy when detecting that the difference between the paced S1 amplitude and the intrinsic S1 amplitude is less than a specified threshold difference.
11. A method of controlling operation of a medical device system, the method comprising:
measuring a parameter of an intrinsic S1 heart sound using a heart sound sensor of the medical device system;
delivering electrical pacing stimulation to two or more of a plurality of cardiac pacing sites;
measuring a parameter of a paced S1 heart sound for the two or more of the plurality of cardiac pacing sites;
generating an indication of a pacing site of the plurality of pacing sites for pacing stimulation using a comparison of the intrinsic S1 heart sound parameter and the paced S1 heart sound parameter measured for the two or more of the plurality of pacing sites; and
delivering pacing stimulation using the indicated pacing site.
12. The method of claim 11 , wherein the measuring the parameter of the intrinsic S1 heart sound and the measuring the parameter of the paced S1 heart sound includes measuring amplitude of the intrinsic S1 heart sound and measuring amplitude of the paced S1 heart sound, and wherein generating the indication of a pacing site includes generating the indication of a preferred pacing site using a difference between the amplitude of the intrinsic S1 heart sound and the amplitude of the paced S1 heart sound measured for the two or more of the plurality of pacing sites.
13. The method of claim 12 , wherein generating the indication of a preferred pacing site includes generating the indication of a pacing site as the pacing site with the largest difference between the amplitude of the paced S1 heart sound parameter and the amplitude of the intrinsic S1 heart sound parameter.
14. The method of claim 11 , including sensing a cardiac signal representative of electrical cardiac activity using the medical device system; identifying a pacing site as a viable pacing site when a difference between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound satisfies a specified threshold difference; and selecting the indicated pacing site from identified viable pacing sites using a parameter determined from the sensed cardiac signal.
15. The method of claim 14 , including: determining a ventricular activation time interval value using the sensed cardiac signal, delivering electrical pacing pulses to the plurality of pacing sites; identifying a subset of the plurality of pacing sites as the viable pacing sites using the comparison of the intrinsic S1 heart sound amplitude and the paced S1 heart sound amplitude; and selecting the indicated pacing site from the subset of viable pacing sites using the ventricular activation time interval value.
16. The method of claim 14 , including measuring a plurality of differences between amplitude of paced S1 heart sounds and amplitude of the intrinsic S1 heart sound for the plurality of pacing sites and determining the threshold difference from the determined plurality of differences.
17. The method of claim 11 , including: sensing a cardiac signal representative of electrical cardiac activity using the medical device system; determining an intrinsic ventricular activation time interval value using the sensed cardiac signal; identifying a subset of the plurality of cardiac pacing sites using the intrinsic ventricular activation time interval value, delivering the electrical pacing stimulation to the subset of the cardiac pacing sites; and selecting the indicated pacing site from the subset of the cardiac pacing sites using the intrinsic S1 heart sound parameter and the paced intrinsic S1 heart sound parameter.
18. The method of claim 17 , wherein the intrinsic ventricular activation time interval value includes one or more of a time interval between a Q-wave and left ventricular activation (Q-LV interval), a time interval between right ventricular activation and left ventricular activation (RV-LV) interval, and a time delay between activation of an atrium and activation of a ventricle (AV delay).
19. The method of claim 11 , including: sensing a cardiac signal representative of electrical cardiac activity using the medical device system; determining a time interval between an R-wave of the sensed cardiac signal and the intrinsic S1 heart sound (intrinsic R-S1 interval); determining a paced R-S1 interval; and generating the indication of a pacing site using a difference between the intrinsic R-S1 interval and the paced R-S1 interval.
20. The method of claim 11 , including: generating the indication of a pacing site using a difference between amplitude of the paced S1 heart sound and amplitude of the intrinsic S1 heart sound; and generating an indication of a weak response to electrical pacing therapy when detecting that the difference between the paced S1 amplitude and the intrinsic S1 amplitude is less than a specified threshold difference.