FR2477886A1 - HEART STIMULATION DEVICE - Google Patents

Abstract

THE HEART STIMULATION DEVICE, INTENDED TO PROVIDE STIMULATION POINTS AND TO AVOID PROVIDING THEM DURING NORMAL HEART BEATS IN ASSOCIATION WITH CIRCUITS 6 FOR DETECTION OF SPONTANEOUS BEATS OF THE HEART AND OF CONTROL CIRCUITS 9 DELIVERING THE STIMULATING POINTS AT THE HEART 10, INCLUDES AN OPERATING SET AT TEST RATE 2, CAN BE CONTROLLED EXTERNAL BY A MAGNETIC DEVICE 1, AND A SYNCHRONIZER 4 TO SYNCHRONIZE THIS TEST MODE TO THE SPONTANEOUS BEATS OF THE HEART.

Description

The present invention relates to devices

stimulation of the heart, and more particularly,

  inhibited type positive that can be implanted.

  Pacemakers of the following types of reserve, on demand, inhibited, or synchronized include a means for changing them from a reserve or detection state to a fixed rhythm operating state.

  predetermined which allows several tests of the device to be carried out

positive, and its system, for example, testing the battery voltage, which is indicated by a deviation from the

  test rate and / or the width of the stimulation tip

tion; the stimulation threshold; malfunctions

of the electrode system, and other parameter measurements.

This predetermined fixed test rhythm induces competition

  between the spontaneous heart rate and the pace of stimulation

lation of the stimulation device.

  This competition can result in phe-

nomenes of points on T, this letter representing a

  vulnerable heart disease, and can be dangerous if

coronary insufficiency.

The object of the present invention is to reduce

  this risk by introducing a synchronization of the rhythm fi-

  test and spontaneous heart rate.

  2. In addition, there is a need for pacing of the heart to terminate the tachyarrhythmia by returning to the normal sinus rhythm. Nowadays, this is

obtained by stimulation of the heart with electric spikes

  high frequency until conversion is achieved

  desired. The synchronization system, subject of the pre-

  sente invention, produces stimulation peaks during the diastole period, which has the effect of terminating the tachyarrhythmia more effectively and without creating

risk of over-stimulation.

  According to one of the characteristics of this

  invention, means are provided to terminate the tachyary-

  thmia in patients with implanted pacemakers of the on-demand or other type, thanks to the application of pacing of the heart at a frequency

predetermined higher. According to a pre-

  fere of the present invention, there are provided means for applying a stimulation tip in order to stop the cardiac tachyarrhythmia, this tip being applied during the diastole period, and means for repeating

  such stimulation peaks, if necessary, in syn-

chronism with heartbeats, and to repeat a

such stimulation at predetermined intervals.

  The device according to the invention is based on

  conventional circuits, and preferably on logical circuits

  with C-MOS technology (metal-oxide semiconductor

  which require a current from the energy source

  low intensity. A linear circuit means can also

  Also be used in such devices.

The present invention will be well understood during

the following description made in relation to the drawings

  attached in which: FIG. 1 is a block diagram of a pacemaker of the inhibited type comprising a synchronizer according to the present invention; Figure 2 is a flowchart showing the processing of the synchronizer signal; 3.

  Figure 3 is an electrocardiogram shown

  feeling the characteristics of the synchronizer according to the

  present invention in the case of two spikes of stimulation

predetermined tion. The intervals are given for reference; and Figure 4 is a typical logic solution based on a CMOS circuit for n stimulation peaks

predetermined where n is an integer.

  FIG. 1 represents a block diagram of a pacemaker of the type

  inhibited in combination with the synchronizer, according to the pre-

invention, where the reference 10 represents the heart.

In this diagram, reference 3 represents the block comprising

both the synchronizer 4 and its connections with the others

blocks. When the "test" operating mode is requested

  die by means of an external control device 1 (magnet for example), and its receiver 2 (reed switch by

  example), the synchronizer responds by detecting

  line synchronization signals 7. These signals are of one of the following types: either the heartbeat activity segment detected by circuits 6, or the stimulation tip provided by a driving circuit 9

  via a line 11. The first of these if-

  general activates the synchronizer circuits to obtain

  set the predetermined number of stimulation spikes; the synchronizer responds by inhibiting by 8 the detection circuits 6 during this period, that is to say until

  when the predetermined number of stimulations is reached.

Simultaneously, the rhythm circuits 5 of the stimulation device pass to a stimulation rhythm level

higher.

  FIG. 2 represents a flow diagram of the treatment

signals from the synchronizer. In this flowchart-

me, reference 20 corresponds to "fixed rhythm test request", reference-21 to "spontaneous beat produced", the

  reference 22 a "emission of a predetermined number of dots

  high-rate ", reference 23 to" tip of stimulation

4.

tion produced ".

  Figure 3 shows a typical electrocardiogram. The duration of the test is defined by reference 57. This diagram shows the synchronization of the test rhythm peaks with respect to the beats 32. The predetermined number of fixed rhythm stimulation peaks has

was determined to be two. (In the pre-

sent, the application of stimulation tips 33, 34 and, forms a sequential combination). The sequence of events represented is described below, in conjunction

with Figures 1 and 3.

  Interval 51 is an interval between bat-

  spontaneous hearts (interval said R-R). During this interval 51, a test rhythm is initialized; so

  beat 32 is the first synchronization beat

  tion with which the synchronizer 4 inhibits the detection circuits 6 during the two stimulation intervals 52 and 53. These stimulation intervals are shorter than the rhythm interval 54, and are established according to clinical criteria. The stimulation peaks 33 and 34 are produced by the rhythm circuits 5, with the higher rhythm controlled by the synchronizer 4. During the

reception of the second stimulation tip 34, the syn-

  timer 4 cancels inhibition 8 and detection of the pacemaker resumes. In the example now described, no spontaneous beats were received during the basic stimulation interval 54, which led to the application of an inherently produced stimulation tip 35

  by the rhythm circuit 5. The tip 35 converts the syn-

  timer for two successive intervals 55 and 56, limited by the high-rate stimulation tips 36 and 37. As the request for the "test" operating mode ended some time after the stimulation tip 37, the synchronizer stopped its intervention and from this point it assumes its normal functions of detection and rhythm. The synchronizer can be incorporated in

  any combination and length of period 57.

5. FIG. 4 represents an example of a real solution where standard logic circuits of the C-MOS type are used. An offset register 63 is used as a counter for a predetermined number of stimulations during the fixed rate test. This register is in the state

initial unless the "test" mode is requested by a circuit

  cooked 64. In the initial state, the Ql output which is used

  to control a 68 "circuit inhibition command

  tection and increase- of rhythm "is at level zero,

  so that neither the inhibition of detection nor the increase

the rhythm does not occur. At the request of

  "test" mode an OR 66 door releases the initial state of the

  register 63 and the first pulse applied to the CL input of register 63 in the form of synchronization signals

61 takes this register to the logical level "UN". The exit

  tie Ql causes inhibition, through the

  cooked 68, from detection 6 of the stimulator and causes a high stimulation rate from the rhythm circuits 5. The next set of stimulation tips will advance the shift register 63 until Qn, which is the ( nl) he counting of the stimulation peaks, passes to the logical level "UN". Qn being at logic level "UN" makes entry D of register 63 pass to logic level

"ZERO" and so the next point received at CL will have the ef-

  to pass Ql to the logical level "ZERO". This will have the effect of canceling both the inhibition command and the higher rate 68 and will reset the

  shift register via a differentiation-

  67 or door OR 66. From this state, the syn-

  timer waits for synchronization signal, upon re-

  except that new synchronization cycles are produced as described above. It will repeat itself so much

  that the "test" operating mode will be required.

  The stimulator according to the present invention has

is assessed on a number of countries

  patients who were equipped with demand stimulators. At

At the time of the test, the synchronizer triggers the switching

  6. blade tester and synchronization signals, thus controlling the rhythm circuits in order to obtain a higher rhythm and at the same time inhibiting the detection circuits

for two rhythm intervals per synchronization cycle

station. In fact, when fixing the magnet, the first

  R wave, or tip of the stimulator, which occurs every

days the first switches the rhythm to "test" mode for two consecutive peaks, ie, for example at a rate of 100 pulses per mm. Then there is a return to the detection mode during an interval and, once again during the production of R or of a stimulator tip, two tips are emitted at the same frequency or at another

predetermined frequency. This can be repeated as long-

time as necessary. Two consecutive spikes, at in-

  fixed ranges, generally suitable in the assessment

  tion of the stimulator system. Twenty patients are connected

  temporarily to a pacemaker synchronized according to the present

  the invention. An average of 200 synchronized tests is

  done by patient and recorded for evaluation purposes.

  The peak of the T phenomenon is detected in less than 5% of the periods, compared to an average of 45% for conventional magnet tests. Preliminary tests indicate that the new device is effective in ending the

tachyarrhythmia of patients.

  It appears that the new concept of synchronization

tion of pacemaker trials with the heart rate and that this timing during the application of pacing tips to end tachyarrhythmia can be applied to many types of pacemakers and that such instruments and applications are found in

  the framework and in the spirit of the present invention.

  The present invention is not limited to the examples

  ples of realization which have just been described, it is on the contrary susceptible of variants and modifications

  which will appear to those skilled in the art.

7.

Claims (4)

  1 - Cardiac stimulation device intended to provide stimulation points, and to avoid provide these spikes when detecting normal beats   heart ailments, combined with electrode means for de-   tect such spontaneous heartbeats and to provide   to define such stimulation points in the heart of the patient, characterized in that it includes a test rhythm mode   which can be controlled externally, a means being pre-   seen to synchronize said beating test mode spontaneous from the heart.   2 - Cardiac stimulation device according to claim l, characterized in that it comprises a means of rhythm at a predetermined frequency and a means for doing   re the test at one or more predetermined rhythms. 3 - Cardiac stimulation device according to the   claim 2, characterized in that the frequency of the rhythm   test me is greater than that of spontaneous beats   of the heart, or that of the rate of rhythm of stimulation tion. 4 - Device according to one of claims 1   to 3, characterized in that it comprises a means for putting   end tachyarrhythmia, which includes means for applying   quer a stimulation peak in the diastole period of the heartbeat and to repeat such peaks, as necessary, at predetermined intervals, said spikes being synchronized with spontaneous heartbeats. - Cardiac stimulation device according to one of claims 1 to 4, characterized in that the   test rhythm is initialized by the application of an external magnetic field, by piezoelectric means, by electromagnetic waves, by acoustic means or by a light signal.