Systems and methods for therapy titration in heart failure

Abstract

Systems and methods for treating a medical condition such as worsening heart failure (WHF) are described. A medical system may sense one or more physiological signals, and generate from the sensed physiological signals a signal metric trend indicating a progression of heart failure. A detector may detect a physiological event leading to WHF. A therapy control circuit may generate a therapy titration protocol using the generated signal metric trend. The therapy titration protocol includes a temporal profile of therapy dosage relative to a target dosage. The therapy control circuit may adjust the target dosage based on patient response. Therapies may be administered by a clinician or automatically delivered to the patient according to the therapy titration protocol.

What is claimed is: 
     
         1 . A system for adjusting a therapy delivered to a patient, the system comprising:
 a physiological event detector circuit configured to:
 generate a composite signal metric using a plurality of physiological signals sensed from the patient; and 
 trend the composite signal metric over time; and 
   a therapy control circuit configured to adjust a therapy parameter in response to the trended composite signal metric satisfying a predetermined trend condition.   
     
     
         2 . The system of  claim 1 , wherein the therapy delivered to the patient includes an electrostimulation therapy,
 wherein to adjust the therapy parameter includes to adjust an electrostimulation parameter in response to the trended composite signal metric satisfying the predetermined trend condition.   
     
     
         3 . The system of  claim 1 , wherein the therapy delivered to the patient includes an drug therapy,
 wherein to adjust the therapy parameter includes to adjust a drug dosage in response to the trended composite signal metric satisfying the predetermined trend condition.   
     
     
         4 . The system of  claim 1 , wherein the physiological event detector circuit is configured to detect a worsening heart failure (WHF) event using the trended composite signal metric,
 wherein the therapy control circuit is configured to adjust the therapy parameter further in response to the detection of the WHF event.   
     
     
         5 . The system of  claim 1 , wherein the therapy control circuit is configured to generate a therapy titration protocol including values of the therapy parameter varied over time relative to a target therapy parameter value. 
     
     
         6 . The system of  claim 5 , wherein the values of the therapy parameter are varied in accordance with the trended composite signal metric. 
     
     
         7 . The system of  claim 6 , wherein the therapy titration protocol includes a stepwise change in the values of the therapy parameter in accordance with the trended composite signal metric. 
     
     
         8 . The system of  claim 5 , wherein the target therapy parameter includes a baseline electrostimulation parameter value for an electrostimulation therapy, or a baseline drug dosage for a drug therapy. 
     
     
         9 . The system of  claim 5 , wherein the therapy control circuit is further configured to, when the values of the therapy parameter are above the target therapy parameter value for a predetermined time period, increase the target therapy parameter value to a level corresponding to a lowest therapy parameter value during the predetermined time period. 
     
     
         10 . The system of  claim 5 , wherein the therapy control circuit is further configured to:
 evaluate a patient response to a therapy delivered over a monitoring time period in accordance with a lower therapy parameter value than the target therapy parameter value; and   change the target therapy parameter value to the lower therapy parameter value if the patient response indicates no worsening of the physiological condition during the monitoring time period.   
     
     
         11 . The system of  claim 1 , wherein to adjust the therapy parameter, the therapy control circuit is configured to:
 increase an electrostimulation energy or a drug dosage in response to the trended composite signal metric indicating an increasing trend; and   maintain or decrease the electrostimulation energy or the drug dosage in response to the trended composite signal metric indicating a decreasing trend.   
     
     
         12 . The system of  claim 1 , wherein to adjust the therapy parameter, the therapy control circuit is configured to:
 increase an electrostimulation energy or a drug dosage in response to the trended composite signal metric exceeding a composite signal metric threshold value; and   maintain or decrease the electrostimulation energy or the drug dosage in response to the trended composite signal metric falling below the composite signal metric threshold value.   
     
     
         13 . A method of adjusting a therapy dosage in a patient using a medical system, the method comprising:
 receiving a plurality of physiological signals sensed from a patient;   generating a composite signal metric of the received plurality of physiological signals using a physiological event detector circuit;   trending the composite signal metric over time using the physiological event detector circuit; and   adjusting a therapy parameter in response to the trended composite signal metric satisfying a predetermined trend condition.   
     
     
         14 . The method of  claim 13 , wherein the therapy delivered to the patient includes an electrostimulation therapy,
 wherein adjusting the therapy parameter includes adjusting an electrostimulation parameter in response to the trended composite signal metric satisfying the predetermined trend condition.   
     
     
         15 . The method of  claim 13 , wherein the therapy delivered to the patient includes an drug therapy,
 wherein adjusting the therapy parameter includes adjusting a drug dosage in response to the trended composite signal metric satisfying the predetermined trend condition.   
     
     
         16 . The method of  claim 13 , comprising generating a therapy titration protocol including values of the therapy parameter varied over time relative to a target therapy parameter value. 
     
     
         17 . The method of  claim 16 , wherein the values of the therapy parameter are varied in accordance with the trended composite signal metric. 
     
     
         18 . The method of  claim 16 , comprising, when the values of the therapy parameter are above the target therapy parameter value for a predetermined time period, increasing the target therapy parameter value to a level corresponding to a lowest therapy parameter value during the predetermined time period. 
     
     
         19 . The method of  claim 13 , wherein adjusting the therapy parameter includes:
 increasing an electrostimulation energy or a drug dosage in response to the trended composite signal metric indicating an increasing trend; and   maintaining or decreasing the electrostimulation energy or the drug dosage in response to the trended composite signal metric indicating a decreasing trend.   
     
     
         20 . The method of  claim 13 , wherein adjusting the therapy parameter includes:
 increasing an electrostimulation energy or a drug dosage in response to the trended composite signal metric exceeding a composite signal metric threshold value; and 
 maintaining or decreasing the electrostimulation energy or the drug dosage in response to the trended composite signal metric falling below the composite signal metric threshold value.