PACEMAKER WITH CONTINUOUSLY ADJUSTABLE OUTPUT AMPLITUDE

• US 3,777,762 A
• Filed: 01/08/1971
• Issued: 12/11/1973
• Est. Priority Date: 12/22/1970
• Status: Expired due to Term

• Current Assignee: Lars Stig Nielsen
• Original Assignee: Lars Stig Nielsen
• Inventors: Nielsen, Lars Stig
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/104,952
• Time in Patent Office: 1,068 Days
• Field of Search: 128/419P,421,422,2.5P,2.6R,2.1A,2.5R
• US Class Current: 607/27
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: H03K 3/53 by the use of an energy-accumulating element discharged through the load by a switching device controlled by an external signal and not incorporating positive feedback H03K3/335 takes precedence

Abstract

A pacemaker having an output control circuit which is adapted when activated to control the produced pace impulses in such a manner that the amplitude of each impulse is slightly less than that of the preceding impulse. The control circuit can be activated and deactivated from outside, either by suitable hospital equipment or manually by a surgeon. It permits the threshold value of the heart to be determined without surgical operation by ascertaining the smallest pace impulse that causes heart contraction.

Claims

1. An implantable device comprising pulse generator means for producing heart stimulating pacing pulses including amplitude means for setting the amplitude of the pacing pulses, electrode means for introducing the pacing pulses into a heart, and circuit means coupled to said pulse generator means which coacts with the amplitude means thereof to set the amplitude of the pacing pulses produced by said pulse generator means, said circuit means including self-contained control means which when activated will cause the circuit means to change automatically in a continuous manner the coaction with the amplitude means of the pulse generator means and switch means for external actuation while the device is implanted which in repose normally deactivates the control means under which circumstances the circuit means coacts with the amplitude means of the pulse generator means to set the amplitude of the pacing pulses to a fixed value, said switch means when actuated, activates the control circuit whereby the amplitude of the pacing pulses are automatically varied.

2. An implantable device as defined in claim 1, wherein said switch means is a reed switch actuatable by a magnetic member.

3. An implantable device as defined in claim 1, whereby said switch means is an electronic switch means including a tuned high frequency circuit actuatable by a preselected high frequency generator.

4. An implantable device as defined in claim 1 whereby said switch means comprises a reed switch actuatable by a magnetic member in series with a tuned high frequency circuit actuatable by a preselected high frequency generator.

5. An implantable device as defined in claim 1 wherein said switch means is a piezoelectric crystal actuatable at a preselected ultrasonic frequency.

6. An implantable device as defined in claim 1 wherein said pulse generator means includes a condenser the discharge from which is fed to said electrode means and said amplitude means controls the amplitude to which the condenser is charged.

7. An implantable device as defined in claim 1 wherein said amplitude means includes a voltage follower device coacting with said circuit means.

8. An implantable device as defined in claim 7 whereiN said voltage follower device is a field effect transistor.

9. An implantable device as defined in claim 1 wherein said circuit means includes a condenser and resistor in series with the junction therebetween connected to said amplitude means.

10. An implantable device as defined in claim 9 wherein said switch means in repose short circuits the condenser of said circuit means and when actuated relieves the short circuit.