Heart pacemaker

• US 5,088,491 A
• Filed: 03/23/1990
• Issued: 02/18/1992
• Est. Priority Date: 09/17/1985
• Status: Expired due to Term

• Current Assignee: Biotronik Mess-Und Therapiegeraete GmbH & Company Ingenieurbuero Berlin (Biotronik SE & Company KG)
• Original Assignee: Biotronik Mess-Und Therapiegeraete GmbH & Company Ingenieurbuero Berlin (Biotronik SE & Company KG)
• Inventors: Schaldach, Max
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US07/501,305
• Time in Patent Office: 697 Days
• Field of Search: 128/419 PG
• US Class Current: 607/18
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters

Abstract

A cardiac pacemaker for implanting in a patient includes a device for applying stimulating pulses to the heart of the patient at a rate determined by a pacing parameter; a device for detecting a first physiological parameter which is correlated with physical exertion of the patient and producing a first output signal representative of the first physiological parameter; a circuitry device receiving the first output signal for varying the pacing parameter as a function of the first output signal received as an input variable; and the circuitry device being a closed-loop control device which receives first output signal from the device for detecting the first physiological parameter, for determining one of (a) the product of the heart rate and the stroke volume and (b) the product of the heart rate and a single variable representative of the stroke volume as the cardiac output, to correspond to changes in the first output signal which represents a standard for the current physical exertion of the patient, for varying the pacing parameter.

Claims

1. A cardiac pacemaker for implanting in a patient, comprising:

means for applying stimulating pulses to the heart of the patient at a rate determined by a pacing parameter;

means for detecting at least a first physiological parameter which is correlated with physical exertion of the patient and producing a first output signal representative of said at least first physiological parameter;

means for providing a second output signal corresponding to the heart rate and a third output signal corresponding to the stroke volume or a variable representative of the stroke volume; and

circuitry means, receiving said first second and third output signals, for varying the pacing parameter as a function of said first outpout signal received as an input variable, said circuitry means including a closed-loop control means for determining the product of said second and third output signals as the cardiac output, and for regulating the pacing parameter to vary the stimulation rate to cause said product to change corresponding to changes in said first output signal, which represents a standard for the current physical exertion of the patient.

2. A pacemaker as defined by claim 1, wherein said circuitry means further comprises:

a memory having a plurality of memory locations containing data;

means for producing a first address signal as a function of said first physiological parameter;

means for producing at least one further address signal;

means for addressing said plurality of memory locations as a function of said first address signal and said further address signal and for outputting the addressed data as a further output signal;

wherein said circuitry means receives said first output signal for varying the pacing parameters as a function of said first outout signal which is received as an input variable;

said circuitry means being responsive to the addressed data which is received by said circuitry means as said further output signal; and

wherein the data which is contained in said memory, and which is output as said further output signal, forms a characteristic data field for effecting control of said pacing parameter, said characteristic data field being addressable as a data unit; and

linking means for linking each said characteristic data field with further corresponding characteristic data fields.

3. A pacemaker as defined by claim 2, wherein a control characteristic curve in the characteristic field HZV=f(Sv, HR), where HZV represents cardiac output, SV represents stroke volume, and HR represents heart rate, is stored in said memory and is addressed by said means for addressing.

4. A pacemaker as defined by claim 1 wherein said means for detecting includes at least two measured value pickups for producing respective signals dependent on physical exertion of the patient, and means for receiving and combining said signals from said at least two measured value pickups to produce said first output signal which is dependent on each of the signals received from said at least two measured value pickups;

and wherein the respective said signals received from said at least two measured value pickups represent measured values corresponding to at least one of (a) the measurement variables PEP and LVET, (b) resistance increase, (c) blood temperature, (d) respiration rate, (e) QT interval, (f) blood oxygen saturation, (g) pH value, (h) the orientation of the pacemaker in space, and (i) accelerations having a predetermined minimum intensity which serve as an indication of activity of the patient.

5. A cardiac pacemaker for implanting in a patient comprising:

means for applying stimulating pulses to the heart of the patient at a rate determined by a pacing parameter;

means for detecting a first physiological parameter which is correlated with physical exertion of the patient and producing a first output signal representative of said first physiological parameter;

circuitry means, receiving said first output signal, for varying the pacing parameter as a function of said first output signal received as an input variable; and

said circuitry means being a closed-loop control means which receives said first output signal from said means for detecting the first physiological parameter, for determining the product one of (a) the heart rate and the stroke volume and (b) the heart rate and a variable representative of the stroke volume, as the cardiac output, and for varying the pacing parameter to cause said product to change corresponding to change in said first output signal which represents a standard for the current physical exertion of the patient; and

second means for detecting, and means for determining systolic time intervals with said means for determining systolic time intervals being fed by said second means for detecting, and with said means for determining systolic time intervals supplying an output signal representing the systolic time intervals to said circuitry means; and

wherein the said circuitry means determines a parameter that varies in accordance with the stroke volume based upon the signal representing the systolic time intervals supplied by said means for determining the systolic time intervals, and said second means for detecting includes a sensing means which senses at least one of (a) intracardial pressure, (b) sound, and (c) an impedance corresponding to an impedance cardiogram.

6. A pacemaker as defined by claim 5, further comprising a stimulation electrode, and at least one additional sensing means disposed on said stimulation electrode.

7. A cardiac pacemaker for implanting in a patient comprising:

means for applying stimulating pulses to the heart of the patient at a rate determined by a pacing parameter;

means for detecting a first physiological parameter which is correlated with physical exertion of the patient and producing a first output signal representative of said first physiological parameter;

circuitry means, receiving said first output signal, for varying the pacing parameter as a function of said first output signal received as an input variable; and

said circuitry means being a closed-loop control means which receives said first output signal from said means for detecting the first physiological parameter, for determining the product one of (a) the heart rate and the stroke volume and (b) the heart rate and a variable representative of the stroke volume, as the cardiac output, and for varying the pacing parameter to cause said product to change corresponding to change in said first output signal which represents a standard for the current physical exertion f the patient; and

calibration means for calibrating said means for detecting, and a further detecting means having an output signal representing a second measured value, and compensation means;

said first means for detecting being identical with said second means for detecting, and each said compensation means remains substantially unchanged for a following operating period of time.

8. A pacemaker as defined by claim 7, further comprising an external measured value pickup means feeding one of said calibration means, and wherein said calibration means effects calibration in response to said external measured value pickup means which is connected, during said operating period of time, to said communication means.