Apparatus for sensing and transmitting a pacemaker's stimulating pulse

• US 4,151,513 A
• Filed: 03/06/1975
• Issued: 04/24/1979
• Est. Priority Date: 03/06/1975
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Barthel, Thomas C., Menken, John D., Brastad, Brian A.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Groody, James J.
• Application Number:
  US05/555,897
• Time in Patent Office: 1,510 Days
• Field of Search: 340/206, 340/180, 128/2.1 A, 128/419 PT, 128/2.05 R, 128/2.06 R, 179/2 DP, 307/225 R
• US Class Current: 340/870.24
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/37282 characterised by communication with experts in remote locations using a network

Abstract

Apparatus is disclosed for sensing and transmitting the stimulating pulse of an implanted pacemaker over readily available, low-bandwidth transmission media to a remote receiver capable of measuring the pulse width to provide an indication of the condition of the pacemaker energy source, e.g. a battery. In particular, the sensing and transmitting apparatus detects the electrical activity, e.g. the EKG, of a patient through attached electrodes and modulates a carrier or tone of a suitable frequency to be transmitted over the low-bandwidth transmission medium to the receiver, along with a pulse signal multiplied by a selected, fixed factor dependent upon the carrier frequency of the signal and the other information to be transmitted to the receiver. Illustratively, a factor in the range of 30-50 is selected where it is desired to transmit the pulse width of the pacemaker stimulating pulse along with an EKG, to a receiver to be displayed in a manner to permit evaluation of the EKG and of the width of the stimulating pulse. Typically, the patient in which the pacemaker is implanted has a transmitter for transmitting the aforementioned data to a receiver located in the doctor'"'"'s office, clinic or hospital, whereby a regular check of the pacemaker'"'"'s energy source may be made by the patient'"'"'s doctor.

Claims

1. Apparatus for providing and transmitting together stimulating pulses as applied by an artificial pacemaker to a patient'"'"'s heart and an electrocardiac signal of the patient'"'"'s heart over a limited bandwidth medium to a remote station, said apparatus comprising:

(a) modulation means for generating a carrier signal of a frequency to be transmitted over the limited bandwidth medium;

(b) means for providing a multiplied signal of a pulse width corresponding to the pulse width between the leading and trailing edges of the stimulating pulse multiplied by a fixed factor;

(c) means for superimposing and applying the multiplied signal and the electrocardiac signal together to said modulation means, whereby the superimposed signals are transmitted over the limited bandwidth medium, the fixed factor selected to be not less than 30 and not more than 50 to insure that data of the multiplied signal is accurately transmitted over the limited bandwidth medium at the carrier frequency and does not obscure the electrocardiac signal; and

(d) receiving apparatus for receiving the stimulating pulses as transmitted over the limited bandwidth medium and including display means for displaying an indication of the pulse width of the stimulating pulse, artifact detector means responsive to the transmitted signal for separating the stimulating pulse from other signals, means for detecting the leading and trailing edges of the separated stimulating pulse signal and for providing signals indicative thereof, clock means for providing clock pulses, and counter means responsive to the output of said detection means for counting the number of clock pulses occuring during the pulse width of the stimulating pulse to provide an output indicative thereof and display means responsive to the output of said counter means for providing display of the pulse width information.

2. The system as claimed in claim 1, wherein said receiving apparatus includes divider means responsive to the clock pulses of said clock means for applying clock pulses to said counter means at a rate whereby the count information displayed by said display means corresponds to the multiplied pulse width of the stimulating pulse.