BIDIRECTIONAL HEART STIMULATOR

• US 3,563,247 A
• Filed: 03/14/1968
• Issued: 02/16/1971
• Est. Priority Date: 03/14/1968
• Status: Expired due to Term

• Current Assignee: David L. Bowers
• Original Assignee: David L. Bowers
• Inventors: Bowers, David L.
• Application Number:
  US04/713,110
• Time in Patent Office: 1,069 Days
• US Class Current: 607/13
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators

Abstract

An implantable electronic heart stimulator has a coupling capacitor in series with the subject'"'"''"'"'s heart to which it is electrically connected. Electronic switches sequentially apply a pulse of one polarity for stimulating the heart by charging the capacitor and apply a second stimulating pulse of opposite polarity by discharging the capacitor. An electronic timer controls the electronic switches. Means are provided for increasing the pulse repetition rate externally of the subject.

Claims

1. An electric heart stimulator comprising:

a. a series circuit including a coupling capacitor and a pair of terminals that are adapted for being connected to a heart which is to be stimulated;

b. a DC power source having opposite polarity terminals;

c. first and second semiconductor switch means connected serially with each other across the terminals of the power source, and each of said switch means being adapted to conduct current in opposite direction, respectively;

d. the said series circuit having one of its ends connected at a point intermediate the semiconductor switches and its other end connected to one terminal of the power source;

e. a bistable multivibrator having an output terminal on which alternate potential changes occur repetitively at a rate that corresponds with the stimulation rate of the heart, said semiconductor switches being connected to said output terminal and each of said switches being rendered alternately conductive in response to the alternately occurring potential changes on said output terminal;

f. whereby one of the semiconductor switches may conduct to charge said coupling capacitor from the source and impart current in one direction through the heart to stimulate a heartbeat and then the other semiconductor switch may conduct to discharge the coupling capacitor and impart current in the opposite direction through the heart to stimulate the next consecutive heartbeat;

g. a generator of single polarity pulses which occur at a constant repetition rate corresponding with the desired heart stimulation rate, said generator having aN output terminal on which the pulses occur; and

h. said bistable multivibrator having an input trigger terminal receiving pulses from said pulse generator output terminal and responding to each such pulse by producing alternate potential changes on the multivibrator output terminal as aforesaid.

2. The invention set forth in claim 1 wherein:

a. said pulse generator includes a timing resistor and a timing capacitor in series and connected across said power source;

b. diode means connected to a terminal of the power source and in series with a conducting path through said bistable multivibrator, to thereby produce a predetermined bias voltage drop across said diode means;

c. a first transistor having an emitter, a base and a collector, and a capacitor connected on one side to the emitter and on the other side to a point intermediate said timing capacitor and resistor, the base of said first transistor being connected to said diode means, charging of said timing capacitor eventually causing the voltage drop across said timing resistor to fall below the diode bias voltage to thereby forward bias said first transistor; and

d. a second transistor having an emitter, a base and a collector, the collector of the first transistor being connected to the base of the second transistor whereby said first and second transistors are forward biased together to produce the single polarity pulses on an output terminal of the second transistor.