WO1988003822A1 - Appareil pour stimulation cardiaque transoesophagienne, mis en oeuvre avec un seuil d'energie reduit au minimum, et methode de stimulation s'y rapportant - Google Patents

Appareil pour stimulation cardiaque transoesophagienne, mis en oeuvre avec un seuil d'energie reduit au minimum, et methode de stimulation s'y rapportant Download PDF

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Publication number
WO1988003822A1
WO1988003822A1 PCT/IT1987/000098 IT8700098W WO8803822A1 WO 1988003822 A1 WO1988003822 A1 WO 1988003822A1 IT 8700098 W IT8700098 W IT 8700098W WO 8803822 A1 WO8803822 A1 WO 8803822A1
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WO
WIPO (PCT)
Prior art keywords
stimulation
pulse
electrodes
cardiac
leads
Prior art date
Application number
PCT/IT1987/000098
Other languages
English (en)
Inventor
Gino Grassi
Paolo Marconi
Original Assignee
C.B. Bioelettronica S.R.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by C.B. Bioelettronica S.R.L. filed Critical C.B. Bioelettronica S.R.L.
Publication of WO1988003822A1 publication Critical patent/WO1988003822A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/3625—External stimulators
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0517—Esophageal electrodes

Definitions

  • Apparatus for t ransoesophagea L cardiac stimulation implemented with a minimized energy threshold, and a relative method of stimulation.
  • the invention disclosed relates to an apparatus for transoesophagea I cardiac stimulation that, features minimization of the cardiac stimulus threshold, and to a relative method of stimulation.
  • One of the problems connected with transoesophageal cardiac stimulation is the discomfort caused to the patient, a factor due to the relatively high levels of energy that are required conventionally for an efficient stimulation. This situation arises from the fact that the electrical stimulus transmitted by the probe must be geared to somewhat high thresholds in order to compensate for the indirect nature of the contact created between the cardiac muscle and the electrode, which occurs via adipose tissue and muscular bundles; such intervening layers in fact produce a high dielectric rigidity in the capacitive medium thus created.
  • An additional problem is that of the need to effect a recording of the cardiac signal immediately after stimulation ceases, in order to monitor the response of the patient's heart.
  • Transoesophageal stimulation is currently effected utilizing apparatus capable of generating a square wave pulse of strength greater than the stimulus threshold, much in the same way as is effected with external electrodes (applied to the chest ) or with pacemakers implanted directly in the cardiac muscle. Given the particular type of use and the positioning of these two expedients, however, the aforementioned problems are not encountered; external stimulation of the heart is effected in emergencies for the most part, where no monitoring requirement exists, whilst the output generated by a conventional pacemaker is extremely low. -*
  • each burst of stimulation involves the delivery of a high amount of energy, which occasions discomfort to the patient; more exactly, the energy put out at the moment of stimulation, i.e. at the moment the pulse is generated, produces a capacitive effect through the living tissues, polarizing the oesophagus wall.
  • this polarizing type of stimulation which implies using signals generally of between 300 and 500mV and >300msec duration, it becomes impossible to effect a recording of cardiac response, as the return signals are of extremely low strength, around 1mV.
  • the object of the invention is that of overcoming the drawbacks described above by limiting the amount of energy generated in transoesophageal stimulation, and attenuating its polarizing effects.
  • the stated Object is achieved with an apparatus for transoesophageal stimulation as characterized in the appended claims.
  • the problems outlined above are defeated by adopting an apparatus capable of generating stimulation pulses of sinusoidal, or triangular, or similar waveform, in combination with compensating pulses of opposite polarity, which are equivalent in terms of energy output while remaining below the cardiac stimulus threshold Level.
  • a first advantage provided by the invention consists essentially in the fact that the physical discomfort experienced with cardiac stimulation is lessened, thanks to a considerable limitation of the amount of energy transmitted.
  • sine wave and triangular pulses generate energy levels one half and one third, respectively, of that delivered by a pulse of square waveform.
  • Practical research has in fact shown that it is the peak amplitude of a cardiac stimulation pulse that is important, not the energy output.
  • Another advantage of the invention is the facility it provides of effecting a more immediate recording of cardiac response, since the polarizing effect of stimulation is minimized.
  • the compensating pulse produces no stimulation of the cardiac cells, but serves simply to obtain an inverse polarity such as will cancel out, or at least drastically reduce, the polarizing effects of stimulation.
  • a further object of the invention is thus to embody a probe for use in conjunction with the apparatus disclosed, that will render transoesophageal card ac stimulation and recording a much less uncomfortable process than with the probes currently utilized.
  • an oesophageal probe as characterized in the appended claims, which incorporates at least three electrodes that are substantially spherical, or at all events, devoid of sharp edges or surface roughness, so that no spiking effect will occur when the stimulation pulse is discharged; moreover, the electrodes are enveloped in a capsule fashioned from gastrically soluble material, and can be ingested orally.
  • a further advantage of the invention is the minimum discomfort to which individuals are subjected during stimulation, a factor which reduces the likelihood of emotional disturbance triggered by its effects in those patients for whom a calm state is essential.
  • fig 1 is a graph illustrating the waveform of three pulses, one conventional and two according to the invention, which are superimposed to allow a more immediate comparison
  • fig 2 is a block diagram illustrating an example of the circuit in apparatus according to the invention
  • fig 3 illustrates the arrangement of the electrodes in an oesophageal probe as disclosed, viewed in plan, packaged for ingestion by the patient
  • fig 4 is the section through a probe as disclosed, viewed following ingestion, positioned in readiness both to transmit stimulation pulses, and to receive signals reflecting cardiac response.
  • the method of transoesop ageal cardiac stimulation disclosed, and the apparatus for its implementation, provide for the generation of stimulation pulses 1 exhibiting sine wave or triangular wave shape, as i I lust rated in fig 1.
  • the different stimulation pulses 1q, 1s and 1t are illustrated in superimposed format; it will be seen immediately that the energy generated in each case, i.e. the area subtended by each waveform, differs in considerable measure.
  • the apparatus generates not only a stimulation pulse 1, but a compensating pulse 2 besides; the peak value of this additional pulse remains below the cardiac stimulus threshold in absolute terms, and its polarity is inverted in relation to the stimulation pulse 1.
  • the width of the inversely polarized compensating pulse 2 is adjusted in such a way that its energy output substantially matches that of the stimulation pulse 1; accordingly, the polarizing effect of the stimulation pulse 1 can be drastically reduced, if not eliminated altogether.
  • the compensating pulse 2 is indicated in fig 1 as preceding the stimulation pulse 1; whilst this would be the preferred sequence, its inversion will alter nothing in practice.
  • a possible embodiment of the apparatus is shown in the block diagram of fig 2, where the probe 13 is connected to a pulse generator 11 and to a pulse recorder 12, e.g. an electrocardiograph.
  • 3 denotes a. blanking module operated by the pulse generator 11, and 14 a filter; these two stages are connected in series between the pulse generator and recorder. More exactly, the blanking module 3 is embodied as. a switch interlocked to the pulse generator 11, and will be activated to break the circuit into which it is wired, for the duration of the stimulation and compensating pulses 1 and 2.
  • a compensating pulse 2 renders it possible, if not to eliminate entirely, then at least to ensure a drastic reduction in the polarizing effect of the stimulation pulse 1.
  • the signal returned by the probe 13, whi ch ⁇ ref lects cardiac activity and is much weaker than that attributable to the polarizing effects of the stimulation pulse 1 will be discernable by the recorder 12 only when stimulation ceases, hence in real time. Any residual interference will be taken out by the filter 14.
  • the oesophageal probe 13 incorporates at least three electrodes denoted 4, 5 and 6; each is substantially spherical in shape, and at all events, free of sharp edges and roughness.
  • the endmost electrodes 4 and 6 are connected firmly to respective leads 8 and 10 returned to the pulse generator 11.
  • the middle electrode ' 5 is connected to the recorder 12, via a further lead denoted 9. In practice, there might be four or even more electrodes, in which case at least one of those located in the middle must be connected to the recorder 12.
  • the electrodes 4, 5 and 6 are contained in a capsule 7, of gastrically soluble material; the dimensions of the electrodes 4, 5 and 6 and the capsule 7 will be such that the probe is easily swallowed, and good contact established between the electrodes and the oesophagus wall 15 (fig 4).
  • the size of a suitable capsule for general use might be, say, 6 x 18mm.
  • the middle electrode/s 5, that is, connected to the recorder 12, might be embodied smaller than the end electrodes 4 and 6 connected to the pulse generator 11, as the wall 15 of the oesophagus will generally shrink around the electrode regardless, enveloping it almost entirely Cfig 4
  • the length of the leads 8, 9 and 10 is dissimilar, so that with the capsule 7 swallowed and dissolved, the electrodes 4, 5 and 6 will simply gravitate to the required level, extending the leads 8, 9 and 10 as in fig 4.
  • Contact with the oesophagus wall 15 is enhanced by providing the electrodes 4, 5 and 6 with an axial bore; the leads 8 and 9 of the two farthest electrodes 4 and 5 thus pass through the nearest 5 and 6, which remain uppermost following destruction of the capsule 7.
  • the two leads 8 and 9 might pass loosely through the two electrodes 5 and 6, as in fig 3, which illustrates the leads gathered into the capsule 7, or might be attached to them firmly.
  • each lead 8, 9 and 10 will be selected in such a way that with the capsule 7 dissolved, the distance between the stimulation electrodes 4 and 6, i.e. those located endmost and wired up to the pulse generator 11, will be optimum -viz, 30mm approx.
  • the electrodes 4, 5 and 6 might exhibit a shape other than spherical, as shown in figs 3 and 4, provided that the probe 13 retains its dynamic configuration, combining the advantage of oral ingestion with that of small dimensions of the electrodes 4, 5 and 6, and with that of a low cardiac stimulus threshold, this ensured by optimum distancing of the electrodes at approx 30mm apart, as aforementioned.
  • the electrodes 4, 5 and 6 wilt be spherical, to facilitate their extraction, and the leads 8, 9 and 10 will be thin, ultra-flexible and well-insulated wires made fast mechanically to the electrodes as in figs 3 and 4.

Landscapes

  • Health & Medical Sciences (AREA)
  • Cardiology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Electrotherapy Devices (AREA)

Abstract

L'appareil est conçu pour générer une impulsion de stimulation (1) de forme d'onde sinusoïdale ou triangulaire qui s'élève au-dessus du seuil de stimulus cardiaque, et une impulsion de compensation (2) de polarité inverse qui est équivalente en termes d'énergie mais demeure inférieure à la valeur de seuil; on utilise une sonde oesophagienne comportant au moins trois électrodes dont les extrêmes (4, 6) sont raccordées à un générateur d'impulsions (11), et dont la ou les centrales (5) sont raccordées à un enregistreur d'impulsions (12).
PCT/IT1987/000098 1986-11-20 1987-11-19 Appareil pour stimulation cardiaque transoesophagienne, mis en oeuvre avec un seuil d'energie reduit au minimum, et methode de stimulation s'y rapportant WO1988003822A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT3581A/86 1986-11-20
IT8603581A IT1216198B (it) 1986-11-20 1986-11-20 Ne cardiaca transesofagea con apparecchiatura per la stimolaziominimizzazione della soglia di stimolazione e metodo relativo a tale stimolazione

Publications (1)

Publication Number Publication Date
WO1988003822A1 true WO1988003822A1 (fr) 1988-06-02

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IT1987/000098 WO1988003822A1 (fr) 1986-11-20 1987-11-19 Appareil pour stimulation cardiaque transoesophagienne, mis en oeuvre avec un seuil d'energie reduit au minimum, et methode de stimulation s'y rapportant

Country Status (2)

Country Link
IT (1) IT1216198B (fr)
WO (1) WO1988003822A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0518546A2 (fr) * 1991-06-11 1992-12-16 Physio-Control Corporation Stimulateur cardiaque à courant réduit
US5191885A (en) * 1989-02-06 1993-03-09 Arczo Medical Electronics, Inc. Method of terminating an arrhythmia
US5343860A (en) * 1989-02-06 1994-09-06 Arzco Medical Systems, Inc. Esophageal recording/pacing catheter with thermistor and cardiac imaging transceiver

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2241287A1 (en) * 1973-08-20 1975-03-21 Siemens Ag Circuit for heart implant pacemaker - reduced charging time of output capacitor supplying stimulation pulses
DE2619001A1 (de) * 1976-04-29 1977-11-10 Siemens Ag Herzschrittmacher
EP0010908A1 (fr) * 1978-10-19 1980-05-14 Michigan Instruments. Inc. Appareil de réanimation cardiopulmonaire
WO1981003428A1 (fr) * 1980-06-03 1981-12-10 P Pless Sonde a electrode oesophagienne pour la stimulation electrique du coeur
DE3327561A1 (de) * 1982-09-28 1984-03-29 VEB Transformatoren- und Röntgenwerk "Hermann Matern", DDR 8030 Dresden Oesophaguselektrodensonde

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2241287A1 (en) * 1973-08-20 1975-03-21 Siemens Ag Circuit for heart implant pacemaker - reduced charging time of output capacitor supplying stimulation pulses
DE2619001A1 (de) * 1976-04-29 1977-11-10 Siemens Ag Herzschrittmacher
EP0010908A1 (fr) * 1978-10-19 1980-05-14 Michigan Instruments. Inc. Appareil de réanimation cardiopulmonaire
WO1981003428A1 (fr) * 1980-06-03 1981-12-10 P Pless Sonde a electrode oesophagienne pour la stimulation electrique du coeur
DE3327561A1 (de) * 1982-09-28 1984-03-29 VEB Transformatoren- und Röntgenwerk "Hermann Matern", DDR 8030 Dresden Oesophaguselektrodensonde

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5191885A (en) * 1989-02-06 1993-03-09 Arczo Medical Electronics, Inc. Method of terminating an arrhythmia
US5343860A (en) * 1989-02-06 1994-09-06 Arzco Medical Systems, Inc. Esophageal recording/pacing catheter with thermistor and cardiac imaging transceiver
EP0518546A2 (fr) * 1991-06-11 1992-12-16 Physio-Control Corporation Stimulateur cardiaque à courant réduit
EP0518546A3 (en) * 1991-06-11 1993-01-27 Physio-Control Corporation Reduced current cardiac pacing apparatus
US5330506A (en) * 1991-06-11 1994-07-19 Physio-Control Corporation Reduced current cardiac pacing apparatus

Also Published As

Publication number Publication date
IT8603581A0 (it) 1986-11-20
IT1216198B (it) 1990-02-22

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