Tripolar catheter apparatus

• US 4,289,134 A
• Filed: 07/23/1979
• Issued: 09/15/1981
• Est. Priority Date: 07/23/1979
• Status: Expired due to Term

• Current Assignee: Electro-Catheter Corporation
• Original Assignee: Electro-Catheter Corporation
• Inventors: Bernstein, Robert I.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/059,523
• Time in Patent Office: 785 Days
• Field of Search: 128/419 P, 128/419 PG, 128/419 PT
• US Class Current: 607/9
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

A tripolar catheter apparatus employing an automatic electronic switch is adapted for use with a conventional bipolar demand cardiac pacer for converting a bipolar pacing system into a tripolar pacing system in which stimulation can be applied between two intra-ventricular electrodes, such as ones located in the right ventricular apex, while sensing of ventricular depolarization may be obtained by an intra-ventricular apical electrode and an extra-ventricular electrode located outside the ventricle, such as in the right atrium or vena cava. The tripolar catheter apparatus comprises a pair of catheter terminals connected to the output terminals of the bipolar demand cardiac pacer and three output electrodes, namely a proximal electrode, a medial electrode and a distal electrode, which are provided to the heart. The distal electrode is the common electrode for both sensing and stimulation in the tripolar system while an automatic electronic switch selects either the proximal electrode or the medial electrode dependent on the provision of a cardiac stimulus from the pacer.

Claims

1. A tripolar catheter apparatus connectable to a bipolar demand cardiac pacer having a common pacer terminal pair for providing both cardiac depolarization sensing and cardiac stimulation in a human patient dependent on the mode of said pacer, said sensing being provided in a sensing mode and said stimulation being provided in a stimulation mode, said catheter being insertable through a portion of the patient'"'"'s curculatory system into the heart, said tripolar catheter apparatus comprising a first catheter terminal connected to one pacer terminal of said pacer common terminal pair, a second catheter terminal connected to the other pacer terminal of said pacer common terminal pair, a first proximal electrode, a second medial electrode, a third distal electrode and switch means responsive to the provision of a cardiac stimulus from said pacer, said switch means being connected between said first catheter terminal and said medial and proximal electrodes for selecting either said medial or proximal electrode dependent on the provision of said cardiac stimulus from said pacer, said distal electrode being connected to said other catheter terminal irrespective of said selection of said medial or distal electrode, said distal and medial electrodes comprising intra-ventricular electrodes, said proximal electrode comprising an extra-ventricular electrode, said switch means being responsive to the provision of said cardiac stimulus from said pacer in said pacer stimulating mode for providing said stimulus to the heart between said intra-ventricular distal and medial electrodes during the presence of said cardiac stimulus, said switch means being responsive to said pacer sensing mode for providing said depolarization sensing from the heart between said intra-ventricular distal electrode and said extra-ventricular proximal electrode, whereby said bipolar demand cardiac pacer is usable as a tripolar demand cardiac pacer.

2. A tripolar catheter apparatus in accordance with claim 1 wherein said medial electrode is connected in parallel to said proximal electrode through a diode switch means, said diode switch means being conductive in response to the presence of said cardiac stimulus at said first catheter terminal for providing said cardiac stimulus between said medial and distal electrodes.

3. A tripolar catheter apparatus in accordance with claim 2 wherein a first resistive impedance R is connected between said proximal electrode and said first catheter terminal, a physiological impedance Z_p being present between said proximal and distal electrodes when said catheter apparatus is connected to the heart, and said cardiac pacer has an associated input impedance Z_i with said resistive impedance R being related to said physiological impedance Z_p in accordance with a voltage divider ratio of Z_p /(R+Z_p) when said cardiac stimulus is present at said first catheter terminal, where Z_p <

R.

4. A tripolar catheter apparatus in accordance with claim 3 wherein in said pacer sensing mode, said resistive impedance R is further related to said cardiac pacer input impedance Z_i in accordance with a voltage divider ratio of Z_i /(R+Z_i), where Z_p <

R<

Z_i.

5. A tripolar catheter apparatus in accordance with claim 4 wherein the value of the ratio Z_p /(R+Z_p) is in the range of 4% to 25%.

6. A tripolar catheter apparatus in accordance with claim 5 wherein the value of the ratio Z_p /(R+Z_p) is substantially equal to 5%.

7. A tripolar catheter apparatus in accordance with claim 5 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

8. A tripolar catheter apparatus in accordance with claim 7 wherein the value of the ratio Z_i /(R+Z_i) is substantially equal to 90%.

9. A tripolar catheter apparatus in accordance with claim 8 wherein the value of the ratio Z_p /(R+Z_p) is substantially equal to 5%.

10. A tripolar catheter apparatus in accordance with claim 4 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

11. A tripolar catheter apparatus in accordance with claim 2 wherein said diode switch means comprises a bidirectional diode switch means conductive in response to the presence of said cardiac stimulus at said first catheter terminal irrespective of the polarity of said first catheter terminal.

12. A tripolar catheter apparatus in accordance with claim 11 wherein said bidirectional diode switch means comprises a pair of diodes connected in parallel with opposite polarities.

13. A tripolar catheter apparatus in accordance with claim 12 wherein said bidirectional diode switch means further comprises a second resistive impedance R₂ connected in parallel with said parallel connected diode pair for providing a high impedance leakage current path in the opposite direction to the normal direction of current flow to said medial electrode.

14. A tripolar catheter apparatus in accordance with claim 2 wherein said diode switch means comprises at least a first diode and a resistive impedance R₂ connected in parallel with said first diode for providing a high impedance leakage current path in the opposite direction to the normal direction of current flow to said medial electrode.

15. A tripolar catheter apparatus in accordance with claim 14 wherein another resistive impedance R is provided between said proximal electrode and said first catheter terminal, the value of said resistive impedance R₂ being at least twice the value of said other resistive impedance R.

16. A tripolar catheter apparatus in accordance with claim 1 wherein a first resistive impedance R is connected between said proximal electrode and said first catheter terminal, a physiological impedance Z_p being present between said proximal and distal electrodes when said catheter apparatus is connected to the heart, and said cardiac pacer has an associated input impedance Z_i with said resistive impedance R being related to said distal-proximal electrode physiological impedance Z_p in accordance with a voltage divider ratio of Z_p /(R+Z_p) when said cardiac stimulus is present at said first catheter terminal, where Z_p <

R.

17. A tripolar catheter apparatus in accordance with claim 16 wherein in said pacer sensing mode, said resistive impedance R is further related to said cardiac pacer input impedance Z_i in accordance with a voltage divider ratio of Z_i /(R+Z_i), where Z_p <

R<

Z_i.

18. A tripolar catheter apparatus in accordance with claim 17 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

19. A tripolar catheter apparatus in accordance with claim 16 wherein the the value of the ratio Z_p /(R+Z_p) is in the range of 4% to 25%.

20. A tripolar catheter apparatus in accordance with claim 19 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

21. A tripolar catheter apparatus in accordance with claim 1 wherein said first catheter terminal is an anode and said second catheter terminal is a cathode.

22. In a cardiac pacing system comprising a bipolar demand cardiac pacer having a common pacer terminal pair for providing both cardiac depolarization sensing and cardiac stimulation in a human patient dependent on the mode of said pacer, said sensing being provided in a sensing mode and said stimulation being provided in a stimulation mode, and a catheter means insertable through a portion of the patient'"'"'s circulatory system into the heart, the improvement comprising a tripolar catheter apparatus as said catheter means, said tripolar catheter apparatus comprising a first catheter terminal connected to one pacer terminal of said pacer common terminal pair, a second catheter terminal connected to the other pacer terminal of said pacer common terminal pair, a first proximal electrode, a second medial electrode, a third distal electrode and switch means responsive to the provision of a cardiac stimulus from said pacer, said switch means being connected between said first catheter terminal and said medial and proximal electrodes for selecting either said medial or proximal electrode dependent on the provision of said cardiac stimulus from said pacer, said distal electrode being connected to said other catheter terminal irrespective of said selection of said medial or distal electrode, said distal and medial electrodes comprising intra-ventricular electrodes, said proximal electrode comprising an extra-ventricular electrode, said switch means being responsive to the provision of said cardiac stimulus from said pacer in said pacer stimulating mode for providing said stimulus to the heart between said intra-ventricular distal and medial electrodes during the presence of said cardiac stimulus, said switch means being responsive to said pacer sensing mode for providing said depolarization sensing from the heart between said intra-ventricular distal electrode and said extra-ventricular proximal electrode, whereby a tripolar demand cardiac pacing system is provided.

23. An improved cardiac pacing system in accordance with claim 22 wherein said medial electrode is connected in parallel to said proximal electrode through a diode switch means, said diode switch means being conductive in response to the presence of said cardiac stimulus at said first catheter terminal for providing said cardiac stimulus between said medial and distal electrodes.

24. An improved cardiac pacing system in accordance with claim 23 wherein a first resistive impedance R is connected between said proximal electrode and said first catheter terminal, a physiological impedance Z_p being present between said proximal and distal electrodes when said catheter apparatus is connected to the heart, and said cardiac pacer has an associated input impedance Z_i with said resistive impedance R being related to said physiological impedance Z_p in accordance with a voltage divider ratio of Z_p /(R+Z_p) when said cardiac stimulus is present at said first catheter terminal, where Z_p <

R.

25. An improved cardiac pacing system in accordance with claim 24 wherein in said pacer sensing mode, said resistive impedance R is further related to said cardiac pacer input impedance Z_i in accordance with a voltage divider ratio of Z_i /(R+Z_i), where Z_p <

R<

Z_i.

26. An improved cardiac pacing system in accordance with claim 25 wherein the value of the ratio Z_p /(R+Z_i) is in the range of 4% to 25%.

27. An improved cardiac pacing system in accordance with claim 26 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

28. An improved cardiac pacing system in accordance with claim 25 wherein the value of the ratio Z_i /(R+Z_i) is in the range of 80% to substantially 100%.

29. An improved cardiac pacing system in accordance with claim 23 wherein said diode switch means comprises a bidirectional diode switch means conductive in response to the presence of said cardiac stimulus at said first catheter terminal irrespective of the polarity of said first catheter terminal.

30. An improved cardiac pacing system in accordance with claim 29 wherein said bidirectional diode switch means comprises a pair of diodes connected in parallel with opposite polarities.

31. An improved cardiac pacing system in accordance with claim 30 wherein said bidirectional diode switch means further comprises a second resistive impedance R₂ connected in parallel with said parallel connected diode pair for providing a high impedance leakage current path in the opposite direction to the normal direction of current flow to said medial electrode.

32. An improved cardiac pacing system in accordance with claim 23 wherein said diode switch means comprises at least a first diode and a second resistive impedance R₂ connected in parallel with said first diode for providing a high impedance leakage current path in the opposite direction to the normal direction of current flow to said medial electrode.