# US 7,744,560 B2 · Implantable drug delivery system responsive to intra-cardiac pressure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,560 B2 - Document ID: US7744560B2 - Status: Granted - Kind: B2 - Application number: 11/289,055 - Filed: 2005-11-29 - Published: 2006-04-06 - Granted: 2010-06-29 - Earliest claimed: 2002-04-22 - Assignees: Medtronic, Inc. - Inventors: Chester Struble - Web page: https://patentgrep.com/patent/US7744560B2 ## CPC - A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition - A61B 5/0031: {Implanted circuitry} - A61M 5/1723: {using feedback of body parameters, e.g. blood sugar or pressure} - A61B 5/7239: {using differentiation including higher order derivatives} - A61M 5/14276: {specially adapted for implantation} - A61M 2205/3523: using telemetric means - A61M 2210/125: Heart - A61M 2230/30: Blood pressure (A61M2230/04 takes precedence) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract The invention is directed to techniques for monitoring the condition of a patient, such as a patient having congestive heart failure, and appropriately modifying the patient's drug therapy as a function of a pressure in the patient's heart, such as the estimated pulmonary artery diastolic pressure. The drugs may be administered by an implanted drug delivery device. The drug selection, the drug dosage or both may be controlled as a function of the pressure and/or the activity level of the patient. ## Claims ### Claim 1 An implantable medical device comprising: a pressure monitor that estimates a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient, a processor that selects a drug that corresponds to the estimated pulmonary artery diastolic pressure, and a pressure sensor that generates a pressure signal as a function of the pressure in the heart of the patient, wherein the pressure monitor comprises a differentiating circuit that generates a derivative signal that is representative of a first derivative of the pressure signal, and wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the derivative signal. ### Claim 2 (depends on 1) The device of claim 1, wherein the processor selects the drug that corresponds to the estimated pulmonary artery diastolic pressure from a look-up table that maps drugs to estimated pulmonary artery diastolic pressures. ### Claim 3 (depends on 1) The device of claim 1, wherein the device is implanted in the abdomen of the patient. ### Claim 4 (depends on 1) The device of claim 1, wherein the pressure sensor includes one of a capacitive absolute pressure sensor, a piezoelectric crystal transducer and a piezoresistive pressure transducer. ### Claim 5 (depends on 1) The device of claim 1, wherein the pressure sensor is disposed in a right ventricle of the heart of the patient. ### Claim 6 (depends on 1) The device of claim 1, wherein the pressure monitor estimates the pulmonary artery diastolic pressure by identifying a pressure value at a point of maximum slope of the pressure signal. ### Claim 7 (depends on 1) The device of claim 1, further comprising a drug delivery device that delivers the selected drug to the patient, wherein the processor generates a control signal as a function of the selected drug, and wherein the drug delivery device receives the control signal and delivers the selected drug to the patient as a function of the control signal. ### Claim 8 (depends on 7) The device of claim 7, wherein the drug delivery device comprises: a reservoir configured to receive and store the selected drug; and an infusion apparatus, that delivers the selected drug to an infusion site. ### Claim 9 (depends on 7) The device of claim 7, wherein the infusion site is one of the subclavian vein, superior vena cava and fatty tissue of the body of the patient. ### Claim 10 (depends on 7) The device of claim 7 wherein the drug delivery device further comprises a pump that delivers the selected drug from the reservoir to a proximal end of the infusion apparatus. ### Claim 11 (depends on 1) The device of claim 1, wherein the selected drug is a drug that increases cardiac output. ### Claim 12 (depends on 1) The device of claim 1, wherein the selected drug is a drug that has a positive inotropic effect on the heart of the patient. ### Claim 13 (depends on 1) The device of claim 1, wherein the selected drug includes one of digitalis, digoxin, digitoxin, dopamine, dobutamine, milrinone and amrinone. ### Claim 14 (depends on 1) The device of claim 1, further comprising an input/output device coupled to the processor, the input/output device configured to exchange information between a person and the processor. ### Claim 15 An implantable medical device comprising: a pressure monitor that estimates a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient, a processor that selects a drug that corresponds to the estimated pulmonary artery diastolic pressure, and a pressure sensor that generates a pressure signal as a function of the pressure in the heart of the patient, wherein the pressure monitor comprises a differentiating circuit that generates a derivative signal that is representative of a second derivative of the pressure signal, and wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the derivative signal. ### Claim 16 (depends on 15) The device of claim 15 further comprising a drug delivery device that delivers the selected drug to the patient, wherein the processor generates a control signal as a function of the selected drug, and wherein the drug delivery device receives the control signal and delivers the selected drug to the patient as a function of the control signal. ### Claim 17 (depends on 16) The device of claim 16, wherein the drug delivery device comprises: a reservoir configured to receive and store the selected drug; and an infusion apparatus, that delivers the selected drug to an infusion site. ### Claim 18 (depends on 17) The device of claim 17, wherein the infusion site is one of the subclavian vein, superior vena cava and fatty tissue of the body of the patient. ### Claim 19 (depends on 17) The device of claim 17 wherein the drug delivery device further comprises a pump that delivers the selected drug from the reservoir to a proximal end of the infusion apparatus. ### Claim 20 (depends on 15) The device of claim 15, wherein the selected drug is a drug that increases cardiac output. ### Claim 21 (depends on 15) The device of claim 15, wherein the selected drug is a drug that has a positive inotropic effect on the heart of the patient. ### Claim 22 (depends on 15) The device of claim 15, wherein the selected drug includes one of digitalis, digoxin, digitoxin, dopamine, dobutamine, milrinone and amrinone. ### Claim 23 (depends on 15) The device of claim 15, further comprising an input/output device coupled to the processor, the input/output device configured to exchange information between a person and the processor. ### Claim 24 A method comprising: estimating a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient; wherein estimating the pulmonary artery diastolic pressure as a function of the pressure comprises: identifying a point of maximum slope in a pressure signal, the pressure signal a function of the pressure in the heart of the patient; and identifying the pressure value at the point of maximum slope in the pressure signal; selecting a drug therapy as a function of the estimated pulmonary artery diastolic pressure; controlling a drug delivery device to deliver a drug to the patient as a function of the selected drug therapy, generating a first derivative of the pressure signal during a cardiac cycle; and sensing the point on the pressure signal that corresponds to a maximum of the first derivative of the pressure signal is maximized. ### Claim 25 (depends on 24) The method of claim 24, wherein selecting the drug therapy as a function of the estimated pulmonary artery diastolic pressure comprises selecting the drug therapy as a function of the estimated pulmonary artery diastolic pressure and an activity level of the patient. ### Claim 26 (depends on 24) The method of claim 24, wherein the pressure is the pressure in the right ventricle of the heart. ### Claim 27 A method comprising: estimating a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient; selecting a drug therapy as a function of the estimated pulmonary artery diastolic pressure; controlling a drug delivery device to deliver a drug to the patient as a function of the selected drug therapy, wherein, estimating the pulmonary artery diastolic pressure as a function of the pressure comprises: identifying a point of maximum slope in a pressure signal, the pressure signal a function of the pressure in the heart of the patient; and identifying the pressure value at the point of maximum slope in the pressure signal by sensing an R-wave of a cardiac cycle; generating the second derivative of the pressure signal during the cardiac cycle; and sensing the point on the pressure signal at which the second derivative of the pressure signal becomes negative after the R-wave. ### Claim 28 (depends on 27) The method of claim 27, wherein estimating the pulmonary artery diastolic pressure comprises estimating the pulmonary artery diastolic pressure each cardiac cycle. ### Claim 29 (depends on 27) The method of claim 27, wherein selecting the drug therapy as a function of the estimated pulmonary artery diastolic pressure comprises selecting at least one of a first drug and a second drug as a function of the estimated pulmonary artery diastolic pressure, and wherein controlling the drug delivery device to deliver the drug as a function of the selected drug therapy comprises controlling the drug delivery device to deliver the selected at least one of the first drug and the second drug. ### Claim 30 An implantable medical device comprising: means for estimate pulmonary artery diastolic pressure comprising a pressure monitor that includes a differentiating circuit; means for select a drug therapy as a function of the estimated pulmonary artery diastolic pressure, wherein the means to select a drug therapy comprises a means to select at least one of a first drug and a second drug as a function of the estimated pulmonary artery diastolic pressure; and means for deliver a drug as a function of the selected drug therapy. ### Claim 31 (depends on 30) The device of claim 30, further comprising means to determine an activity level, wherein the means to select the drug therapy selects the drug therapy as a function of the estimated pulmonary artery diastolic pressure and the determined activity level. ### Claim 32 (depends on 30) The device of claim 30, wherein the means to select a drug therapy comprises a means to select at least one of a first drug and a second drug as a function of the estimated pulmonary artery diastolic pressure. ### Claim 33 An implantable medical device comprising: a pressure monitor that estimates a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient, a processor that selects a drug that corresponds to the estimated pulmonary artery diastolic pressure, a pressure sensor that generates a pressure signal as a function of the pressure in the heart of the patient; and a differentiating circuit that generates a derivative signal that is representative of a first derivative of the pressure signal, wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the derivative signal. ### Claim 34 An implantable medical device comprising: a pressure monitor that estimates a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient, a processor that selects a drug that corresponds to the estimated pulmonary artery diastolic pressure, a pressure sensor that generates a pressure signal as a function of the pressure in the heart of the patient, and a differentiating circuit that generates a derivative signal that is representative of a second derivative of the pressure signal, wherein the pressure monitor estimates the pulmonary artery diastolic pressure as a function of the derivative signal. ### Claim 35 A method comprising: estimating a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient; selecting a drug therapy as a function of the estimated pulmonary artery diastolic pressure; and controlling a drug delivery device to deliver a drug to the patient as a function of the selected drug therapy, wherein estimating the pulmonary artery diastolic pressure as a function of the pressure comprises: identifying a point of maximum slope in a pressure signal, the pressure signal a function of the pressure in the heart of the patient; and identifying the pressure value at the point of maximum slope in the pressure signal by generating the first derivative of the pressure signal; and sensing the point on the pressure signal that corresponds to a maximum of the first derivative of the pressure signal during a cardiac cycle. ### Claim 36 A method comprising: estimating a pulmonary artery diastolic pressure as a function of a pressure in a heart of a patient; selecting a drug therapy as a function of the estimated pulmonary artery diastolic pressure; and controlling a drug delivery device to deliver a drug to the patient as a function of the selected drug therapy, wherein, estimating the pulmonary artery diastolic pressure as a function of the pressure comprises: identifying a point of maximum slope in a pressure signal, the pressure signal a function of the pressure in the heart of the patient; and identifying the pressure value at the point of maximum slope in the pressure signal by sensing an R-wave of a cardiac cycle; generating the second derivative of the pressure signal; and sensing the point on the pressure signal at which the second derivative of the pressure signal during the cardiac cycle becomes negative after the occurrence of the R-wave. ### Claim 37 An implantable medical device comprising: means for estimate pulmonary artery diastolic pressure through a pressure monitor that comprises a differentiating circuit which generates a derivative signal that is representative of a first derivative of the pressure signal; means for select a drug therapy as a function of the estimated pulmonary artery diastolic pressure, wherein the means to select a drug therapy comprises a means to select at least one of a first drug and a second drug as a function of the estimated pulmonary artery diastolic pressure; and means for deliver a drug as a function of the selected drug therapy.