Pacemaker having independently programmable electrode configuration for pacing and sensing and method for operation thereof

• US 4,991,583 A
• Filed: 05/01/1989
• Issued: 02/12/1991
• Est. Priority Date: 08/13/1986
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Siemens Pacesetter, Inc. (Abbott Laboratories)
• Inventors: Silvian, Sergiu
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US07/345,590
• Time in Patent Office: 652 Days
• Field of Search: 128/419 PG
• US Class Current: 607/13
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3686 configured for selecting the electrode configuration on a lead A61N1/3688 takes precedence
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data

Abstract

A pacemaker and a method of operation thereof are provided for configuring or operating a conventional pacemaker having a plurality of lead electrodes. Each lead can be independently configured for any combination of unipolar or bipolar, pacing and sensing. During a pacing mode of operation, a selected return electrode is switchably connected to the most positive battery potential, V_DD. The return electrode of the packemaker, can selectively be either the pacemaker case or one or more ring electrodes. During a fast discharge time period, which occurs immediately subsequent to the delivery of a pacing pulse, the return electrode is disconnected from V_DD and connected to the proximal side of a coupling capacitor through which the pacing pulse has passed. Also during this fast discharge time period, the proximal side of the coupling capacitor is switchable connected to the most negative battery potential, V_SS. During sensing, one input of the sensing amplifier is connected to either the tip electrode or the ring electrode. A second input of the sensing amplifier is switchably connected to the selected return electrode, either the case or the ring electrode. Sensing can therefore occur between tip electrode and ring electrode, tip electrode and case, or ring electrode and case. Furthermore, the case electrode is switchably connected to -0.5 volts during the sensing phase of operation.

Claims

1. An implantable pacemaker, comprising:

a first electrode terminal;

a group of return electrode terminals, said group including a second electrode terminal (20) and a third electrode terminal (18);

means for selecting a return electrode terminal selected from said group of return electrode terminals;

a voltage source (14) having a ground reference potential (V_dd) and a negative reference potential (V_SS) associated therewith;

means (28), coupled to said voltage source, for generating a first reference potential different from said ground reference potential;

pulse generating means (12, C1) for generating a stimulation pulse;

a coupling capacitor (C2) for coupling said stimulation pulse generated by said pulse generating means to said first electrode terminal;

pacing configuration means for electrically connecting said selected return electrode terminal to said ground reference potential only during said stimulation pulse, and for electrically connecting said first electrode to said pulse generator means so that said stimulation pulse is delivered between said first electrode and said selected return electrode; and

fast discharge means for discharging said coupling capacitor towards said first reference potential for said prescribed time period by connecting together said coupling capacitor, said selected return electrode, and said first reference potential for a prescribed time period immediately subsequent to said stimulation pulse, whereby said selected return electrode provides a ground reference during said stimulation pulse and a non-ground reference during a fast discharge time period.

2. The implantable pacemaker of claim 1, wherein said pacing configuration means comprises:

first switch means (P7) for selectively connecting said pulse generating means to said first electrode terminal (16) through said coupling capacitor;

second switch means (P1) for selectively connecting said ground reference potential to said third electrode terminal (18);

third switch means (P2) for selectively connecting said ground reference potential to said second electrode terminal (20); and

control means for generating control signals that control the operation of said first, second and third switching means.

3. The implantable pacemaker of claim 1, wherein said first reference potential is a negative potential corresponding to said negative reference potential (V_ss) of said voltage source.

4. The implantable pacemaker of claim 1, further comprising:

control means for generating a timed sequence of control signals; and

slow discharge means for discharging said coupling capacitor in response to said timed sequence of control signals generated by said control means.

5. The implantable pacemaker of claim 1, wherein said slow discharge means comprises:

a resistor (R1) connected in series with said coupling capacitor and said selected return electrode.

6. An implantable pacemaker, comprising:

a tip electrode terminal (16);

a group of return electrode terminals, said group including a ring electrode terminal (20) and a case electrode terminal (18);

means for selecting a return electrode terminal from said group of return electrode terminals;

a battery (14) having a positive voltage terminal (V_DD) and a negative voltage terminal (V_SS), a prescribed one of said positive or negative voltage terminals comprises a ground reference potential;

pulse generating means (12, C1) for generating a stimulation pulse;

placing configuration means for electrically connecting said selected return electrode terminal to said ground reference potential only during said stimulation pulse, and for electrically connecting said tip electrode to said pulse generator means so that said stimulation pulse is delivered between said tip electrode and said selected return electrode being selected from a group of said case and said second electrode;

sensing means (26), having a first and second input terminal, for sensing electrical signals therebetween; and

programming means for programming an electrode configuration for said sensing means, said electrode configuration including at least two of said case electrode terminal, first electrode terminal and second electrode terminals; and

sensing configuration means for electrically connecting said sensing means to at least two of said case electrode terminal, first electrode terminal and second electrode terminal in accordance with said programming means.

7. The implantable pacemaker of claim 6, wherein said pacing configuration means comprises:

first switch means (P7) for selectively connecting said pulse generating means to said tip electrode terminal (16);

second switch means (P1) for selectively connecting said ground reference potential to said case electrode terminal (18);

third switch means (P2) for selectively connecting said ground reference potential to said ring electrode terminal (20); and

control means for generating control signals that control operation of said first, second and third switching means.

8. The implantable pacemaker of claim 7, wherein said electrode configuration comprises a first and a second electrode terminal, said first electrode terminal being selected from one of said tip and said ring electrode terminals, and said second electrode terminal being selected from one of said case and ring electrode terminals, wherein said sensing configuration means comprises:

fourth switch means (P22, P23) for connecting said first electrode terminal to said first input terminal of said sensing means; and

fifth switching means (P24, P25) for connecting said second electrode terminal to said second input terminal of said sensing means;

wherein said control means further controls operation of said fourth and fifth switching means.

9. The implantable pacemaker of claim 8, further comprising:

a coupling capacitor (C2) having a distal side and a proximal side, said distal side being connected to said tip electrode terminal;

fast discharge means for connecting together said proximal side of said coupling capacitor, said selected return electrode, and said negative voltage terminal of said battery, said connecting being performed in response to control signals generated by said control means, whereby said coupling capacitor is discharged rapidly to the potential of said negative voltage terminal of said battery.

10. The implantable pacemaker of claim 9, wherein said control means comprises:

timing means for generating said control signals in a timed sequence that causes said first switch means and said fast discharge means to perform their respective connections sequentially.

11. The implantable pacemaker of claim 10, further comprising:

a resistor (R1) connected in series with said coupling capacitor and said selected return electrode terminal; and

slow discharge means for discharging said coupling capacitor through said resistor in response to said timed sequence control signals generated by said control means.

12. The implantable pacemaker of claim 8, further comprising:

means (28), coupled to said battery, for generating a first reference potential different from said ground reference potential; and

means for biasing said fourth and fifth switching means to said first reference potential.

13. The implantable pacemaker of claim 12, wherein said biasing means comprises:

a coupling capacitor (C5) having a distal side connected to said tip electrode terminal and a proximal side connected to said fourth switching means;

sixth switching means (P21) for electrically connecting said case to said first reference potential during operation of said sensing means; and

seventh switching means (P30), for connecting said proximal side of said coupling capacitor to said case electrode terminal for a short prescribed time period prior to the operation of said sensing means, wherein said control means further includes generating control signals for controlling said sixth and seventh switching means.

14. The implantable pacemaker of claim 13, wherein said short prescribed time period comprises 50 to 150 microseconds.

15. The implantable pacemaker of claim 12, wherein said first reference potential generated by said reference voltage generator is between -0.2 and -1.0 volts.

16. An implantable pacemaker, for coupling to an implantable lead, comprising:

a stimulating electrode terminal for coupling to the tip electrode of said implantable lead;

a reference terminal;

a voltage source having a ground potential and a first voltage potential (V_SS) associated therewith;

pulse generator means for generating a stimulation pulse, said pulse generator means comprising a storage capacitor, a first side of said storage capacitor being connected to said ground potential, and charge means for charging said storage capacitor from said voltage source;

control means for generating a first control signal having a first pulse width and a second control signal having a second pulse width, said second control signal being generated immediately subsequent to said first control signal;

a coupling capacitor having a distal side and a proximal side, said distal side being connected to said stimulating electrode terminal;

first switch means for connecting said proximal side of said coupling capacitor to a second side of said storage capacitor in response to said first control signal;

second switch means for connecting said reference terminal to said ground potential in response to said first control signal, whereby a stimulation pulse is delivered to the patient'"'"'s heart through said coupling capacitor in response to said first control signal; and

third switch means for connecting together said proximal side of said coupling capacitor, said reference terminal, and said first voltage potential in response to said second control signal, whereby said coupling capacitor discharges to said first voltage potential during said prescribed time period generated by said control means.

17. The pacemaker of claim 16, wherein said implantable lead includes a ring electrode proximal to said tip electrode and said pacemaker further includes a pacemaker case, said pacemaker further comprising:

means for selectively coupling said reference terminal to one of said pacemaker case and said ring electrode of said implantable lead.

18. The pacemaker of claim 17 wherein said control means includes means for generating a third control signal, said pacemaker further comprises:

a voltage reference generator, coupled to said voltage source, for generating a second reference potential;

timing means for generating a timing cycle, said timing cycle having a pacing time interval and a sensing time interval;

sensing means, having a first and second input terminal, for sensing cardiac signals during said sensing time interval; and

fourth switch means for connecting said pacemaker case to said second reference potential in response to said third control signal generated by said control means during said sensing time interval.

19. The sense amplifier of claim 18, wherein said control means includes means for generating a fourth control signal, further comprising:

a second coupling capacitor (C5( connected between said stimulating electrode terminal and said first input terminal of said sensing means; and

fifth switching means (P21), responsive to said fourth control signal, for selectively connecting said pacemaker case to said second reference potential generated by said voltage reference generator means when operating in said sensing mode of operation.

20. The pacemaker of claim 19, wherein said second reference potential is a potential that is no more than 1.0 volt in magnitude as measure width respect to said ground potential.

21. The pacemaker of claim 20, wherein said second reference potential is a negative potential with respect to said ground potential.

22. The pacemaker of claim 21, wherein said second reference potential is approximately -0.5 volts.

23. An implantable pacemaker, comprising:

pacing means for generating a stimulating pulse;

sensing means for sensing cardiac signals;

battery means for providing operating power and first and second voltage reference potentials;

timing means for generating a timing cycle, said timing cycle having a pacing time interval and a sensing time interval;

a tip electrode terminal and a reference electrode terminal for delivering said stimulating pulse from said pacing means during said pacing time interval and for delivering cardiac signals to said sensing means during said sensing time interval; and

switching means for connecting said reference electrode terminal to said first voltage reference potential during said pacing time interval, and for connecting said reference electrode terminal to said second voltage reference potential during said sensing time interval.

24. The pacemaker of claim 23, wherein said first voltage reference potential is the most positive voltage reference potential available from said battery means, and said second voltage reference potential is a voltage reference potential that is 0.2 to 1.0 volts less than said first voltage reference potential.

25. The pacemaker of claim 23, further comprising a voltage reference generator, coupled to said battery, for generating a third voltage reference potential, said pacemaker further comprising:

a coupling capacitor for coupling said pacing means to said tip electrode terminal;

fast discharge means for connecting said coupling capacitor to said third voltage reference potential for a fast discharge time period immediately following the delivery of said stimulating pulse through said coupling capacitor; and

means for switching said reference electrode terminal from said first voltage reference potential to said third voltage potential during said fast discharge time period.

26. The pacemaker of claim 25, wherein said third voltage reference potential is the most negative voltage potential available from said battery means.

27. The implantable pacemaker of claim 25, further comprising a pacemaker case, wherein said reference electrode terminal is said pacemaker case.

28. A method of operating a pacemaker in contact with body tissue, said pacemaker including a tip electrode terminal, and a return electrode terminal, said pacemaker further having a pulse generator for generating stimulation pulses through a coupling capacitor to the tip electrode terminal, said pacemaker further having a voltage source for generating a first voltage potential and a second voltage potential, said method comprising the steps of:

(a) generating a first signal having a first time period and a second signal having a second time period following said first time period;

(b) connecting said first voltage potential (V1) of said voltage source to a proximal side (24) of said coupling capacitor in response to said first signal for said first time period;

(c) connecting a second voltage potential (V_DD) of said voltage source to the return electrode terminal in response to said first signal during said first time period, whereby a stimulating pulse, having a duration equal to said first time period, is delivered through said coupling capacitor to the tip electrode terminal, the tip electrode terminal being connected to a distal side of said coupling capacitor;

(d) disconnecting the return electrode terminal from said second voltage potential (V_DD) in response to said second signal during said second time period;

(e) connecting said proximal side (24) of said coupling capacitor to a discharge potential (V_SS) in response to said second signal for said second time period; and

(f) connecting said proximal side (24) of said coupling capacitor to the return electrode terminal in response to said second signal during said second time period.

29. The method of claim 28, wherein said generating step further comprises generating a third signal having a third time period after said second time period, said method further comprising the step of:

(g) connecting said coupling capacitor to the return electrode terminal through a discharge resistor in response to said third signal for said third time period.

30. The method of claim 28, wherein said pacemaker includes a case electrode terminal and a ring electrode terminal, the method further comprising the initial step of:

selecting the return electrode terminal from one of said case electrode terminal and said ring electrode terminal.

31. A method of sensing cardiac signals in a pacemaker, said pacemaker having a case, a tip electrode terminal, and a ring electrode terminal, and said pacemaker further having means for programming modes of operation of said pacemaker, and sensing means coupled to the tip electrode terminal through a coupling capacitor for sensing cardiac signals, said method comprising the steps of:

(a) programmably selecting one of a first, second, and a third sensing mode of operation;

(b) connecting a first input terminal of a sensing means to the tip electrode terminal through a coupling capacitor in response to said first and said second mode of operation, and to the ring electrode terminal in response to said third mode of operation; and

(c) connecting a second input terminal of said sensing means to the ring electrode terminal in response to said first mode of operation, and to the pacemaker case in response to said second and third mode of operation;

whereby cardiac signals in said first mode of operation are sensed between the tip and ring electrode terminal, cardiac signals in said second mode of operation are sensed between the ring electrode terminal and the pacemaker case, and cardiac signals in said third mode of operation are sensed between the ring electrode terminal and the pacemaker case.

32. The method of claim 31, further comprising the steps of:

(d) providing a voltage source having a ground reference potential and a first reference potential;

(e) connecting the case to said first reference potential during said first, second, and third sensing mode of operation so that the ring electrode terminal is also coupled to said first reference potential through bulk conductance of the pantient'"'"'s heart; and

(f) connecting said first reference potential for a brief duration to the first input terminal of a sensing means, whereby the first and second input terminals of said sensing means are biased to said first reference potential so that voltages above said ground reference potential will be eliminated.

33. The method of claim 32, wherein said first reference potential is a reference potential within the range of -0.2 to -1.0 volts.

34. A method of operating a pacemaker, said pacemaker for coupling to a plurality of electrode terminals, the pacemaker further having a pulse generator means, a voltage reference generator, and a sensing means having a first and a second input terminal, said method comprising the steps of:

(a) providing a sensing mode and a pacing mode of operation;

(b) connecting one of said plurality of electrode terminals to said first input terminal of said sensing means during said sensing mode of operation;

(c) connecting one of said plurality of electrode terminals to said second input terminal of said sensing means during said sensing mode of operation;

(d) connecting one of said plurality of electrode terminals to said first reference potential during said sensing mode of operation;

(e) connecting one of said plurality of electrode terminals to said pulse generating means during said pacing mode of operation;

(f) connecting one of said plurality of electrode terminals to provide a return path for said pulse generating means during said pacing mode of operation; and

(g) connecting said return electrode of step (f) to a ground reference potential during said pacing mode of operation, whereby a simulation pulse is generated.

35. The method of operating a pacemaker as recited in claim 34, wherein said plurality of electrode terminals includes a case electrode terminal, and a tip and a ring electrode terminal for coupling to a bipolar lead having a tip and ring electrode, said pacemaker further having electrode terminal selection means, and wherein step (b) comprises:

selecting one of said tip electrode terminal and ring electrode terminal from the plurality of electrode terminals for connection to said first terminal of said sensing means.

36. The method of operating a pacemaker as recited in claim 35, wherein said (c) comprises:

selecting one of said ring electrode terminal or said case electrode terminal of the pacemaker from the plurality of electrode terminals for connection to said second terminal of said sensing means.

37. The method of claim 34, wherein said first reference potential is a reference potential within the range of -0.2 to -1.0 volts.

38. The method of claim 34, wherein said pacemaker further includes memory means, and solid state switch means responsive to the data stored in said memory means for switching which occurs in steps (b), (c), and (d), said method further comprises the steps of:

storing programming data in said memory means; and

controlling the solid state switch means with said stored programming data, whereby said programming data is used to select the selected sense and return electrodes.

39. A method of configuring a pacemaker, said pacemaker including first and second electrode terminals, and a voltage source having positive and negative voltage terminals, said pacemaker having a timing means for generating a pacing time interval and a sensing time interval, said method comprising the steps of:

(a) generating a voltage reference potential;

(b) generating a stimulation pulse during said pacing time interval between said first electrode terminal and said second electrode terminal;

(c) connecting said second electrode terminal of said pacemaker to said positive voltage terminals of said voltage source during said pacing pacing time interval; and

(d) connecting said second electrode terminal of said pacemaker to said voltage reference potential during said sensing time interval.

40. The method of claim 39, wherein said timing means further is for generating a discharge time period immediately following said pacing time period, the method further comprising:

connecting said second electrode terminal of said pacemaker to said negative voltage terminal of said voltage source during said discharge time period.

41. The method of claim 40, wherein said voltage reference potential is 0.2 to 1.0 volts less than the voltage available at said positive voltage terminal during said sensing mode of operation.

42. A system for configuring a pacemaker, said system comprising:

pulse generator means for generating a stimulation pulse;

sensing means for sensing cardiac signals;

a tip and a return electrode terminal, for delivering stimulating pulses generated by said pulse generator means and for delivering said cardiac signals to said sensing means;

a voltage source having positive and negative voltages terminals;

means for generating a voltage reference potential different from the voltage potential available at said positive and negative voltage terminals;

timing and control means for generating a pacemaker timing cycle, the timing cycle having a pacing time interval during which said stimulating pulse is delivered, a discharge time interval immediately following said pacing time interval, and a sensing time interval for sensing cardiac signals;

means for connecting said return electrode terminal to said positive voltage terminal of said voltage source during said pacing interval;

means for connecting said return electrode terminal to said negative voltage terminal of said voltage source during said discharge time interval; and

means for connecting said return electrode terminal to said voltage reference potential during said sensing mode of operation.

43. The system of configuring a pacemaker of claim 42, further comprising:

a case for housing said pulse generator means, said sensing means, and said voltage source; and

wherein said return electrode terminal is connected to said case.

44. The system of configuring a pacemaker of claim 42, further comprising:

a lead, having a tip electrode and a ring electrode, for coupling between the pacemaker and the patient'"'"'s heart, wherein said tip electrode terminal of the pacemaker is capable of being coupled to said tip electrode of said lead and said return electrode terminal of the pacemaker is capable of being coupled to said ring electrode of said lead.

45. The system of configuring a pacemaker of claim 42, further comprising:

a case for housing said pulse generator means, said sensing means, and said voltage source;

a lead, having a tip electrode and a ring electrode, for coupling between the pacemaker and the patient'"'"'s heart; and

selection means for selecting a return electrode from one of said case and said ring electrode of said lead.