Abstract: An active implantable medical device, especially of the cardiac pacemaker, defibrillator and/or cardiovertor type, and method for the reduction of episodes of arrhythmia, and especially of atrial arrhythmias. The device operates by detecting events of spontaneous electrical activity in a cardiac cavity, especially the atrium; delivering a stimulation to the aforementioned cardiac cavity, which stimulation is controlled according to an actual escape interval such that, at each cardiac cycle, a stimulation is delivered to the cavity if no spontaneous event is detected by the end of a time corresponding to the end of the period of escape interval since the last spontaneous event or the last stimulation in the cavity; counting of the number of successive stimulated events; and discriminating between events detected in the cavity of an extrasystole origin or a non-extrasystole origin.

Abstract: An apparatus and process for the determination of criterion of a frequent presence or of the gravity of atrial and/or ventricular extra-systoles in an active implantable medical apparatus. The signals corresponding to cardiac events in at least one cardiac cavity are detected and the occurrence of extra-systoles are detected. At the detection of every extra-systole, a ponderation (i.e., weight or magnitude of increment) is attributed to the extra-systole, and a count of extra-systoles with the attributed ponderation applied for the detected extra-systole is made. The count also is decremented at each detected cardiac cycle not having a detected extra-systole, such that the decrement also may have an associated ponderation. The count thus provides a criterion of extra-systole frequency and gravity (seriousness).

Abstract: A multi-site pulse generator for the treatment of cardiac insufficiencies by stimulation. In such a multi-site cardiac pulse generator, electrodes are placed in a plurality of distinct respective sites, including at least two ventricular sites. The electrodes are connected to independent outputs of the pulse generator in a manner that allows the detection of a potential of depolarization as well as the application of a stimulation pulse.

Abstract: An active implantable medical device, especially of a cardiac pacemaker, defibrillator and/or cardiovertor type, having a dual chamber stimulation function and protection against cross-sensing atrio-ventricular phenomena. Cardiac events, spontaneous or stimulated, are detected in a first cavity, preferably the atrium, and a second cavity is stimulated, preferably the ventricle, The detection and confirmation of cross-sensing is performed by detecting in the atrium a signal coming from a depolarization consecutive to a preceding stimulation of the ventricle, and distinguishing such a signal from a signal resulting from spontaneous activity of the atrium.

Abstract: A device for filtering cardiac activity signals which receives input signals coming from collected physiological data, and delivers at an output, for processing data, signals spreading, in the frequency domain, over a widened spectral band. A first high-pass filter is used to reduce the extension of the spectral band of the signal received at the input. A compensation stage having a frequency characteristic (32) that is inverted as compared to that of the first high-pass filter is provided. The cut-off frequency (f1) of the first high-pass filter is greater than the low cut-off frequency (fo) of the spectral analysis band. Optionally, a second high-pass filter is provided, whose characteristic (38) presents a cut-off frequency corresponding to the low frequency (fo) of the spectral band. The high frequency of the spectral band may be similarly modified.

Abstract: A device and process for the processing of troubles of the atrial rhythm for an active implantable medical device. The device detects signals from at least the atrial cardiac activity, and stimulates both the atrial and ventricular cardiac cavities, detects the occurrence of atrial extra-systoles (ESA), and determines and releases an intermediate atrial escape interval (PPinter). The intermediate atrial escape interval is then applied during the detection of an atrial extra-systole for improved processing.

Abstract: An active implantable medical device, particularly a cardiac pacemaker, which is enslaved to a signal representative of acceleration, having a measuring circuit (10) comprising at least one sensor (12) delivering a signal of acceleration, and circuits (22-24) to deliver, in response to the signal of acceleration, a parameter of enslavement of at least one function of the device, particularly that of a cardiac stimulation frequency. According to the invention, a circuit (24) operates to limit, in the detection of increase in acceleration, a value linked to the module of the signal of acceleration. Preferably, the limitation is operated on a value proportional to the square of the signal of acceleration, more particularly on a quadratic sum of individual acceleration components (X.sub.i, Y.sub.i, Z.sub.i) according to at least two distinct axes delivered by a respective number of sensors.

Abstract: An active implantable medical device, particularly of the cardiac pacemaker, defibrillator and/or cardiovertor type, having a function of dual chamber cardiac stimulation and a mode of fallback in which a mode of de-synchronisation of the ventricular stimulation occurs when the atrial rhythm exceeds an acceptable level, and a mode of progressive re-synchronisation occurs in the case of a return of the atrial rhythm to the acceptable level. The re-synchronisation is controlled in a conditional manner to be triggered and maintained only if (a) one detects no trouble of the atrial rhythm. In an alternate embodiment the re-synchronisation is triggered and maintained only if, in addition to condition (a): (b) one detects (20) the presence of an effective sinus rhythm.

Abstract: A lead for an implanted medical device, particularly for a cardiac pacemaker, which has at its extremity distal a hollow cylindrical body (10) presenting at its distal side an opening (22) receiving a stimulation electrode (16) which is mounted axially in this opening, the body and electrode being mechanically fixed and set together by gluing the wall of the body to the wall of the electrode. The internal wall of the body is conformed in a manner to provide between the electrode and body, when the electrode is mounted in the body, a peripheral space defining a chamber (30, 34) between the opposing walls (50, 52) of the body and the electrode. This chamber is a glue expansion chamber essentially closed as compared to the exterior except for an injection canal (32) and an escape canal (36).

Abstract: An active implanted medical device, particularly an active implantable medical device, and its external programmer having a bi-directional synchronous transmission of data. The active implanted medical device (10) includes a timing clock (18) and circuits for the emission/reception of signals operating under the temporal control of the timing clock of the active implanted medical device. The programmer (24) includes a timing clock (42) and circuits for the emission/reception of signals, operating under the temporal control of the programmer timing clock.

Abstract: A device for filtering signals emitted by a medical device, principally an active implanted medical device. The device (26) receives an input that is a signal delivered by a circuit (16-24) that receives signals emitted by a medical device (10) in the form of a magnetic induction, in which the medical device has a metallic housing or case. A compensation stage (42) also is provided, having in the frequency domain a transfer function in the form: ##EQU1## where f.sub.c is a chosen parameter according to the geometry and the material of the metallic case of the medical device (10), and where j=.sqroot.-1. The device is useful with medical devices that emit sequences of messages formed by symbols belonging to an alphabet of n symbols (n.gtoreq.2), the compensation stage being able to reduce the rate of inter-symbol interference of collected signals that are applied to it.

Abstract: An active implantable medical device of the defibrillator/cardiovertor type with advanced tachycardia discrimination in which the device monitors the atrial and ventricular activity, suspects and confirms the presence of tachycardia episodes in the monitored activity, and operates a classification algorithm to discriminate between ventricular tachycardias and supra-ventricular tachycardias according to predetermined criteria and a given adjustment of these criteria, and to authorize the releasing of a shock therapy defibrillation, and/or cardioversion and/or anti-tachycardia ventricular stimulation in the presence ventricular tachycardias and to inhibit delivery of a shock therapy in the presence of a supra-ventricular tachycardias, or instead to release an atrial therapy.

Abstract: An active implantable medical device of the defibrillator/cardiovertor type with an improved tachycardia discrimination for utilizing the delivery of a therapy of defibrillation and/or cardioversion and/or antitachycardia stimulation in the ventricle and/or atrium. The atrial and ventricular activity is monitored, and suspected tachycardia episodes in the monitored activity is tested and confirmed, the stability of RR intervals and the stability of associated PR interval are analyzed. The classification discriminates tachycardias detected as between ventricular tachycardias and supra-ventricular tachycardias, and authorizes delivery of a shock therapy in the presence of a confirmed ventricular tachycardias, or inhibits delivery of a shock therapy in response to a confirmed supra-ventricular tachycardia. Where appropriate, the classification also releases an atrial therapy.

Abstract: A ventricular cannulation device. An inner part is placed in the cardiac chamber and an outer part is placed outside the cardiac wall. Each of the inner and outer parts is equipped with means for catching onto the cardiac wall. The inner part bears a means for guiding and attaching the outer part thereto. A tube corresponding to the opening of the cardiac wall serves as a support for an outer tube or a vascular prosthesis. A blood circulatory assistance system is provided using a bio-pump, made from the patient's muscle, and a pulse generator to stimulate the bio-pump under program control, to pump blood from the ventricle. Vascular prosthesis are used to connect the cannulation device and the bio-pump with the aorta for blood flow therethrough.

Abstract: A circuit and process for an active implantable medical device, particularly a cardiac type pacemaker or defibrillator of the "demand" type, for discrimination between parasitic signals and characteristic signals. Such a device includes a detection circuit (10) to collect a cardiac signal (SA), which may be a spontaneous or stimulated cardiac signal, of the bearer of the device. The collected cardiac signal includes a characteristic signal component and undesirable parasitic signal component. The device also includes a discriminating circuit (12-18) and technique for receiving as an input the collected cardiac signal and delivering at an output a signal (ST) desirably corresponding essentially to the characteristic signal, from which any parasitic signals have been removed.

Abstract: The invention protects circuits connected to low energy stimulating (pacing) or detection (sensing) electrodes of an implantable medical device from high energy pulses generated by the device itself or by external devices such as external defibrillators. It also protects cardiac tissue near the low energy electrodes. The invention provides for an automatic and/or foldback-type unidirectional current limiter in each low energy lead. The invention, when applied to an implantable defibrillator/pacemaker, also provides a shock generator presenting pulses to the pacing electrodes only in the direction blocked by the current limiter.

Abstract: A DC/DC converter circuit to convert input source energy to output load energy, for example, a flyback converter to charge a defibrillation storage capacitor from a low-voltage battery in an implantable cardiac defibrillator. The converter allows input current to flow in the flyback inductor for a fixed time, and it allows output current to flow for a time directly proportional to average battery voltage and inversely proportional to the voltage on the capacitor being charged. When used near an electromagnetic communication link, to avoid interference, a control circuit enables and disables the converter at a maximum frequency that is substantially below the operating frequency of the communication link. In addition, the control circuit restricts the converter to transfer energy at a minimum fundamental frequency substantially above the frequency of the communication link.

Abstract: A ventricular cannulation device in which an inner part is placed in the cardiac chamber and an outer part is placed outside the cardiac wall. Each of the inner and outer parts is equipped with means for catching onto the cardiac wall. The inner part bears a means for guiding and attaching the outer part thereto. A tube corresponding to the opening of the cardiac wall serves as a support for an outer tube or a vascular prosthesis.

Abstract: A probe for an implanted medical device, more particularly for a cardiac pacemaker. The probe (10) has at its extremity a cylindrical body (14) supporting one or more electrodes (18) and a means of anchorage (34) extending radially around the exterior. A deformable sleeve (24), made of a supple material, covers the cylindrical body and supports the anchorage means. The sleeve has one end (or part) (26) attached to the body at the distal extremity of the probe, and one part (28) that is free or unconnected to the body spreading proximally in relation to the attached part and supporting the anchorage means. The free part is essentially applied in a separable manner against the body on the aforementioned distal region.

Abstract: A system and methods for the automatic update of the software of an external programmer implant is that is used to program and configure an active implantable medical device implant and acquire data obtained by the implant. The programmer comprises software composed of an assembly of software objects. The implant comprises a memory containing parametric data for the functioning of the implant and an assembly of software objects necessary for the functioning of the programmer in connection with the aforementioned of parametric data. The programmer and the implant communicate bi-directionally.