Cardiac pacemaker

• US 4,932,408 A
• Filed: 03/17/1987
• Issued: 06/12/1990
• 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: Biotronix Mess-Und Therapiegeraete GmbH & Company
• Inventors: Schaldach, Max
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US07/026,678
• Time in Patent Office: 1,183 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 plurality of devices for detecting a corresponding plurality of physiological parameters which are respectively associated with physical exertion of the patient and producing a corresponding plurality of output signals representative of the corresponding physiological parameters; a circuitry device receiving the first output signals for varying the pacing parameter as a function of the first output signal, an external programming device in communication with the circuitry device; a linking element in communication with the external programming devices which selectably links the circuitry device with a selectable one of the plurality of device for detecting; and the external programming device causing the linking element to select a given one of the plurality of detecting device for linking with the circuitry device.

Claims

1. A cardiac pacemaker implantable in a patient, comprising:

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

a plurality of means for detecting a corresponding plurality of physiological parameters which are respectively associated with physical exertion of the patient and producing a corresponding plurality of output signals representative of said corresponding physiological parameters;

circuitry means receiving said first output signal for varying the pacing parameter as a function of said first output signal,

external programming means in communication with said circuitry means; and

a linking means in communication with said external programming means for selectably linking said circuitry means with a selectable one of said plurality of means for detecting;

said external programming means causing said linking element to select a given one of said plurality of detecting means for linking with said circuitry means.

2. A pacemaker as defined by claim 1, wherein said plurality of means for detecting a corresponding plurality of physiological parameters respectively produce a plurality of output signals which represent at least one of (a) fault signals, (b) a number representing the number of signal value fluctuations that exceed a predetermined number within a predetermined period of time, and (c) signals having values which change by an amount exceeding a predetermined amount.

3. A cardiac pacemaker as defined by claim 1, wherein one of said plurality of means for detecting a corresponding plurality of physiological parameters produces a fault signal, and further comprising switchover means which, in the event of fault operation of said circuitry means due to detection of fault signals causes at least one of:

(a) switchover from one mode having a closed control loop to a second mode having direct open-loop control, wherein stroke volume is detected by one of said plurality of means for detecting, and stroke volume is detected by another one of said plurality of means for detecting, the output of said another one of said plurality of means for detecting supplies a signal to said circuitry means so as to form a closed-loop feedback;

(b) shutoff of one of said plurality of means for detecting, and evaluation of the output signals from the remaining ones of said plurality of means for detecting with shutoff of linking means and direct connection of the remaining ones of said plurality of means for detecting;

(c) switchover of the physiologically controlled pacing parameters to fixed values, and (d) return switching after the fault situation is over.

4. A pacemaker as defined by claim 1, wherein said circuitry means includes a memory means storing a predetermined signal level and a preprogrammed order of switching over of said plurality of means for detecting, and further comprising switchover means for causing a switchover among said plurality of means for detecting with said circuitry means, wherein a switchover among said plurality of means for detecting with said circuitry means is effect in said preprogrammed manner when a received signal value corresponds to said predetermined signal value.

5. A pacemaker as defined by claim 1, further comprising a closed-loop control means for causing the cardiac output to correspond to a function of one of (a) a measured variable which is a standard for the current physical exertion and (b) a measured variable derived therefrom, while varying the pacing parameter from a basic pacing rate.

6. A pacemaker as defined by claim 1, further comprising means for detecting a parameter which varies in accordance with the stroke volume, and means for adjusting said parameter which varies in accordance with the systolic time intervals, said parameter being adjusted for the systolic time intervals detected by at least one of (a) intracardial pressure, (b) sound pickups, and (c) an impedance cardiogram by one of said means for detecting which includes resistance measured value pickups disposed in the ventricle.

7. A pacemaker as defined by claim 1, said circuitry means further comprising:

a memory means having a plurality of memory locations containing data;

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

a means for producing at least one further address signal; and

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 second output signal, means for supplying an address signal derived from an input variable and means for supplying at least one further address signal;

said circuitry means for affecting the pacing parameters, during operation, being responsive to the data contained in said memory locations of said memory, wherein the addressing of said memory locations is effected in accordance with the address signal derived from the input variable supplied by said means for supplying an address signal and the at least one further address signal supplied by said means for supplying at least one further address signal.

8. A pacemaker as defined by claim 1, further comprising a linear transmission element for carrying signals detected by one of said plurality of means for detecting which are associated with physical exertion of the patient'"'"'s body.

9. A pacemaker as defined by claim 1, wherein at least two of said plurality of detecting means detect signals which are dependent on physical exertion of the patient, and further comprising additional circuitry means receiving said signals which are dependent on physical exertion of the patient and producing an output signal to said circuitry means that is dependent on both signals which are dependent on physical exertion of the patient.