Method and apparatus for controlling cardiac therapy based on electromechanical timing
Devices and methods for therapy control based on electromechanical timing involve detecting electrical activation of a patient's heart, and detecting mechanical cardiac activity resulting from the electrical activation. A timing relationship is determined between the electrical activation and the mechanical activity. A therapy is controlled based on the timing relationship. The therapy may improve intraventricular dyssynchrony of the patient's heart, or treat at least one of diastolic and systolic dysfunction and/or dyssynchrony of the patient's heart, for example. Electrical activation may be detected by sensing delivery of an electrical stimulation pulse to the heart or sensing intrinsic depolarization of the patient's heart. Mechanical activity may be detected by sensing heart sounds, a change in one or more of left ventricular impedance, ventricular pressure, right ventricular pressure, left atrial pressure, right atrial pressure, systemic arterial pressure and pulmonary artery pressure.
1. A method of treating dyssynchrony of a patient's heart, comprising:
detecting electrical depolarization of a patient's ventricular tissue;
detecting mechanical cardiac activity of the ventricular tissue resulting from the electrical depolarization;
determining a timing relationship between the detected electrical depolarization and the detected mechanical cardiac activity; and
controlling a therapy delivered to the patient based on the timing relationship to treat at least one of intraventricular dyssynchrony and dyssynchrony between the left and right ventricles, wherein at least one of the steps of determining and controlling is implemented at least in part by a circuit.
2. The method of claim 1 , wherein the detected mechanical cardiac activity comprises at least one of contraction and relaxation of the patient's heart.
3. The method of claim 1 , wherein the therapy comprises a therapy to improve interventricular dyssynchrony of the patient's heart.
4. The method of claim 1 , wherein the therapy comprises a therapy to treat at least one of diastolic and systolic dysfunction of the patient's heart.
5. The method of claim 1 , wherein the therapy comprises a therapy to treat at least one of diastolic and systolic dyssynchrony.
6. The method of claim 1 , wherein the therapy comprises a ventricular remodeling reversal therapy.
7. The method of claim 1 , wherein the therapy comprises a therapy to improve dyssynchrony between the left and right ventricles.
8. The method of claim 1 , wherein detecting the mechanical cardiac activity comprises detecting a change in at least one of left ventricular pressure, right ventricular pressure, left atrial pressure, right atrial pressure, systemic arterial pressure and pulmonary artery pressure, indicative of mechanical cardiac activity resulting from the electrical depolarization.
9. The method of claim 1 , wherein detecting the mechanical cardiac activity comprises transthoracically or intrathoracically detecting a change in ventricular impedance indicative of mechanical cardiac activity resulting from the electrical depolarization.
10. The method of claim 1 , wherein detecting the mechanical cardiac activity comprises detecting heart sounds indicative of mechanical cardiac activity resulting from the electrical depolarization.
11. The method of claim 1 , wherein detecting the mechanical cardiac activity comprises detecting a change in blood flow rate or blood perfusion indicative of mechanical cardiac activity resulting from the electrical depolarization.
12. The method of claim 1 , wherein detecting the mechanical cardiac activity comprises detecting ventricular motion or acceleration indicative of mechanical cardiac activity resulting from the electrical depolarization.
13. The method of claim 1 , wherein each of detecting electrical depolarization and detecting mechanical cardiac activity is performed patient-internally.
14. The method of claim 1 , wherein the electrical depolarization of the patient's ventricular tissue is evoked by a pace pulse.
15. The method of claim 1 , wherein the electrical depolarization of the patient's ventricular tissue is caused by intrinsic electrical activation of the patient's heart.
16. The method of claim 1 , wherein controlling the therapy delivered to the patient comprises controlling the therapy to reduce a time interval between the detected electrical depolarization and the detected mechanical cardiac activity.
17. The method of claim 1 , further comprising performing a capture test and detecting capture using the timing relationship.
18. An implantable cardiac device, comprising:
means for detecting electrical depolarization of a patient's ventricular tissue;
means for detecting mechanical cardiac activity of the ventricular tissue resulting from the electrical depolarization;
means for determining a timing relationship between the detected electrical depolarization and the detected mechanical cardiac activity; and
means for controlling a therapy delivered to the patient based on the timing relationship to treat at least one of intraventricular dyssynchrony and dyssynchrony between the left and right ventricles.