Abstract: An active implantable medical device of the cardiac pacing, resynchronization, defibrillation and/or cardio version type able to discriminate between effective and ineffective atrial pacing pulses. This device delivers atrial pacing pulses, collects an endocardial atrial signal, and senses atrial capture. It is able to recognize the presence of an evoked wave consecutive to the delivery of the pacing pulse, by an analysis of the variations of a second derivative of collected signal. A function is calculated based on integrating, over the duration of a window (F) of post-atrial pacing (StimA) atrial sensing, the absolute value of the second derivative (S?) of collected signal (S). The discrimination between effective pacing pulses and ineffective pacing pulses is performed in response to the comparison of a characteristic parameter of said function with a predetermined criterion.

Abstract: An active implantable medical device, preferably a device for pacing, resynchronization, defibrillation and/or cardioversion of a patient, that includes functionality that assists in the diagnosis of the patient's clinical status. This devices comprises circuits (10, 12) for measuring one physiologic parameter, preferably minute ventilation (VE), and circuits (14, 16) for measuring a physical parameter, preferably acceleration (G), control logic (18) for discriminating between activity and rest phases of the patient, and analysis circuits (20-28), to process and combine these signals and memorize (store in memory) the obtained results in the form of a data history. The analysis will establish characteristics providing, for successive dates, representative values, for a given period of time, of the physical signal and physiologic signal during activity phases of the patient, and/or of the physiologic signal during rest phases.

Abstract: An active implantable medical device, notably a device for pacing, resynchronization defibrillation and/or cardioversion, and/or a device for diagnosing patient conditions, having a predictive diagnosis of the patient's status. The device measures a physiologic parameter, notably the minute ventilation (MV); measures a physical parameter, notably the acceleration (G); discriminates between phases of activity and rest of the patient; and includes a memory containing a plurality of fields selectively updated by statistical processing. These fields are comprising one first set (22) containing data related to the patient's activity phases, and one second set (24) containing data related to the patient's rest phases.

Abstract: Apparatus and technique for compensating the potential detected by amplifier circuits for sensing cardiac activity in an active implantable medical device, such as in a pacemaker, defibrillator, cardioverter and multisite device. This device includes circuits for delivering to a cardiac cavity stimulation pulses of predetermined voltage levels and pulse widths, and circuits for sensing cardiac activity comprising an amplifier of signals sensed by an intracardiac electrode, delivering at its output a value of measured potential (Pmeasured) consecutive with the application of a stimulation pulse (I). The device includes circuits for determining a response potential specific to that amplifier, independently of the presence or absence of a myocardial depolarization.

Abstract: An active implantable medical device, such as a cardiac pacemaker, defibrillator, cardiovertor and/or multisite device, able to discriminate noxious and non noxious ventricular extrasystoles. The device is able to detect a heartbeat rate and detect in the rate an occurrence of a ventricular extrasystole (VES). It also is able to measure an intracardiac impedance (Z), correlated with the instantaneous blood flow, and determine, in response to variations of the impedance signal, the presence or the absence of a significant mechanical activity of the myocardium consecutive to the ventricular extrasystole. In response to such variations, the device provides an indicator of the noxious or non noxious character of the ventricular extrasystole. This indicator allows, inter alia, on the following cycle, to adapt in a differentiated way an operating parameter such as the ventricular escape interval, according to the determined noxious or non noxious character of the ventricular extrasystole.

Abstract: An active implantable medical device such as a cardiac pacemaker, defibrillator, cardiovertor and/or multisite device that is able to determine and average a hemodynamic index parameter. The intracardiac impedance signal is correlated to the instantaneous blood flow, and is used to determine periodically an average hemodynamic index (Dave) evaluated over several cardiac cycles under certain preset measurement conditions. For example, the preset conditions include checking that the state of the patient and of the device satisfies, the criteria (stages 12-20) defining predetermined measurement conditions, and inhibiting the determination of the aforesaid hemodynamic index if these criteria are not satisfied. A plurality of samples (Zij) of the measured impedance signal are collected over a length of time (Ti) of the systole of one cardiac cycle.

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator, cardioverter, or multisite device, having an improved cycle to cycle adjustment of the stimulation amplitude. The device stimulates the ventricle, adjusts the stimulation amplitude, periodically evaluates a capture threshold and defines a safety amplitude (Vs), and determines the detection or the loss of a capture on each cardiac cycle after stimulation with a given stimulation amplitude (V). Preferably, the device defines a capture amplitude (Vc) that is higher or equal to the capture threshold, but lower than the safety amplitude.

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator, cardioverter, or multisite device, having an improved cycle to cycle adjustment of the stimulation amplitude. The device stimulates the ventricle, adjusts the stimulation amplitude, periodically evaluates a capture threshold and defines a safety amplitude (Vs), and determines the detection or the loss of a capture on each cardiac cycle after stimulation with a given stimulation amplitude (V). Preferably, the device defines a capture amplitude (Vc) that is higher or equal to the capture threshold, but lower than the safety amplitude.

Abstract: Apparatus and technique for compensating the potential detected by amplifier circuits for sensing cardiac activity in an active implantable medical device, such as in a pacemaker, defibrillator, cardioverter and multisite device. This device includes circuits for delivering to a cardiac cavity stimulation pulses of predetermined voltage levels and pulse widths, and circuits for sensing cardiac activity comprising an amplifier of signals sensed by an intracardiac electrode, delivering at its output a value of measured potential (Pmeasured) consecutive with the application of a stimulation pulse (I). The device includes circuits for determining a response potential specific to that amplifier, independently of the presence or absence of a myocardial depolarization.

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator, cardiovertor, or a multisite device including detection of a risks of a fusion situation. This device is of the double chamber type, and it detects atrial and ventricular events, provides atrial and ventricular stimulation, and delivers a ventricular stimulation pulse after expiration a programmed atrio-ventricular delay (AVD) following the detection of an atrial event (P, A), and in the absence of detection of a ventricular spontaneous event (R) within the AVD. A fusion situation is detected based on an analysis of a sequence of successive cardiac cycles for which the atrio-ventricular delay is modified from one cycle to the next (AVD, AVD+31, AVD+63).