Abstract: Methods and apparatus for capture management in multi-chamber pacing are disclosed. In one embodiment, the invention includes determining a combination of electrodes from a plurality of electrodes that yields the lowest polarization potential immediately following delivery of an electrical stimulus to a heart; and performing capture detection using that combination of electrodes. In order to distinguish loss of capture in one ventricle in bi-ventricular pacing, certain embodiments may also include measuring a width of a QRS complex and determining when the width is greater than a predetermined value. A method for detecting single ventricular loss of capture in bi-ventricular pacing is also described utilizing comparison of evoked QRS complex morphology to a predefined waveform.

Abstract: Methods and devices for improving ventricular contractile status of a patient suitably exploit changes in ventricular pressure and/or dP/dtmax to provide and/or optimize a response to a patient. The ventricular pressure may be appropriately correlated to intracellular calcium regulation, which is indicative of contractile status. To assess ventricular contractile status, the device suitably observes a cardiac perturbation of the patient and measures force interval potentiation following the perturbation. The contractile potentiation can then be stored and/or quantified in the implantable medical device to determine the ventricular contractile status of the patient, and an appropriate response may be provided to the patient as a function of the ventricular contractile status. Examples of responses may include administration of drug or neuro therapies, modification of a pacing rate, or the like.

Abstract: A preferred atrial-based pacing method and apparatus is provided using an intelligent cardiac pacing system to having the ability to continue atrial-based pacing as long as relatively reliable AV conduction is present. In the event that such relatively reliable AV conduction is not present, mode switching to a DDD/R or a DDI/R pacing mode while continually biased to mode switch back to atrial-based pacing. The standard or relatively reliable AV conduction may be changed either automatically or manually. This increases pacing that utilizes natural AV conduction whenever possible so as to gain all the benefits of cardiac contractile properties resulting therefrom, while tolerating the occasional missed ventricular depolarization (i.e., non-conducted P-wave). In the event where relatively reliable AV conduction is not present, the pacing mode is switched to a DDD/R mode while detecting a return of the relatively reliable AV conduction (and resulting mode switch to preferred atrial-based pacing).

Abstract: The present invention is directed to the problem of preventing episodes of “AV Desynchronization Arrhythmia” (AVDA), a dual-chamber pacing behavior that is initiated by a PVC or other ventricular event that is not closely preceded by an atrial depolarization event. If the initiating PVC creates retrograde conduction resulting in an atrial refractory-sensed event, and should the succeeding AP fail to capture due to pacing within the atrial refractory period (ARP) a repetitive AVDA sequence (APineffectual-VP-ARrefractory) can persist for an extended period of time and symptoms of pacemaker syndrome can occur. After AVDA detection, the following may occur: delivered atrial pacing (AP) energy may be (dynamically) increased, a atrial pacing (AP) delay interval may be implemented, a mode-switch may be executed, a patient notification process may begin, a histogram may be recorded or processed, and/or a combination thereof may be used in response the detected AVDA sequence.

Abstract: An analog physiologic signal, e.g., the cardiac EGM, sensed by an IMD is filtered with a high pass filter (HPF), the cut-off frequency of the HPF being within a predetermined frequency bandwidth, wherein a low-band portion of the predetermined frequency bandwidth is attenuated in the filtered physiologic signal. The filtered physiologic signal is digitized in real time order, and the digital data set is filtered in reverse time order employing a digital IIR filter having characteristics substantially matching the cut-off frequency and filter characteristics of the HPF. When the system is implemented within an IMD, the filtered digital data set is compressed by lossy compression algorithm, and the compressed data set is filtered in reverse time order.

Abstract: A medical system incorporating fluid delivery and lead delivery lumens dispense fluid into a volume of tissue. The fluid comprises or contains a pharmacologic, genetic, or biologic agent. The fluid may be dispensed initially during implantation or later using a minimally invasive medical procedure.

Abstract: A system for representing parameter constraints that govern the values of interrelated parameters includes displays corresponding to a plurality of parameters having a range of values represented by a dimension in the displays. The interrelationship of the parameter constraints is maintained, when one or more of the displays change in value, by means of a software system to make an automatic adjustment while recognizing and maintaining the relationship between the parameters. The system is adjustable on a dynamic basis such that when a user adjusts the parameter either upwards or downwards the remaining interrelated parameters are simultaneously shifted to maintain constraints of the relationships consistent with prior condition before the change.

Abstract: Pacing systems are disclosed including detectors for detecting the presence of electromagnetic interference and setting an interference state pacing mode and pacing rate. The interference state pacing mode and pacing rate are altered as a function of patient pacemaker dependency and the prevailing mean heart rate. When pacemaker dependency exists, the pacing rate is maintained and even increased from the prevailing mean heart for the duration of the interference state. When the patient is determined to not be pacemaker dependent, pacing is inhibited or suspended for the duration of the interference state.

Abstract: Cardiac pacing to treat ventricle dysynchrony for improved cardiac function is performed as follows. Early paced inter-ventricular asynchrony is determined during ventricular pacing. Baseline inter-ventricular asynchrony is determined without pacing. Average inter-ventricular asynchrony is calculated by averaging the early paced inter-ventricular asynchrony and the baseline inter-ventricular asynchrony. Atrio-ventricular delay and ventricular-ventricular delay are adjusted during ventricular pacing to yield the average inter-ventricular asynchrony for optimal intra-left ventricular resynchronization and maximal cardiac function. The elements above can be configured in software contained in an implantable medical device or embodied as a computer software product that includes a medium readable by a processor.

Abstract: A hemodynamic status of a patient is determined in an implanted medical device (IMD) by observing a perturbation of the patient's heart, measuring heart rate turbulence resulting from the perturbation, and quantifying the heart rate turbulence to determine the hemodynamic status. The perturbation may be naturally-occurring, or may be generated by the implantable medical device. The patient's response to heart rate turbulence may also be used to provide a response to the patient, such as providing an alarm and/or administering a therapy. Heart rate turbulence may also be used to tune and/or optimize a device parameter such as A-V or V—V pacing intervals.

Abstract: An electrical lead includes an elongate body having a proximal end and a fixation member joined to the elongate body and distally disposed from the proximal end of the elongate body, wherein the fixation member is capable of being extended from and retracted toward the elongate body. A method includes advancing an electrical lead into vasculature and extending a fixation member from the body of the electrical lead to fixedly engage the electrical lead within the vasculature. The method may further include retracting the fixation member toward the body of the electrical lead to unengage the electrical lead within the vasculature and retracting the electrical lead from the vasculature.

Abstract: A method is provided, the method comprising detecting a magnetic resonance imaging (MRI) interference signal and enabling at least one preventive measure to protect an implantable medical device from interference by the magnetic resonance imaging (MRI) interference signal. The method also comprises switching from a first sensing mode more affected by the magnetic resonance imaging (MRI) interference signal to a second sensing mode less affected by the magnetic resonance imaging (MRI) interference signal.

Abstract: An implantable medical device (IMD) for gauging the severity of ischemia in a patient's heart includes a data collection module configured to receive data about the patient's heart, a data processing module configured to process the data to identify an episode of ischemia in the patient and to determine if the episode is stable or unstable, and a reporting module configured to provide an alarm to the patient if the episode is unstable. A method executable by an implantable medical device to detect ischemia in a human heart suitably includes the steps of receiving data about the heart at the implantable medical device, processing the data within the implantable medical device to determine the severity of ischemia, and providing a response from the implantable medical device to the patient if ischemia is indicated.

Abstract: The invention includes a family of miniaturized, hermetic electrical feedthrough assemblies having at least one passive electrical component electrically coupled to a conductive pathway traversing each said assembly which are adapted for implantation within a biological system. The electrical feedthrough assembly according to the invention can be used as a component of an implantable medical device (IMD) such as an implantable pulse generator, cardioverter-defibrillator, physiologic sensor, drug-delivery system and the like. Such assemblies require biocompatibility and resistance to degradation under applied bias current or voltage. Such an assembly is fabricated by interconnected electrical pathways, or vias, of a conductive metallic paste disposed between ceramic green-state material. The layers are stacked together and sintered to form a substantially monolithic dielectric structure with at least one embedded metallization pathway extending through the structure.

Abstract: A plurality of sensors are disposed in and around the heart of a patient to collect data such as various electrical parameters, pressure parameters and temperature parameters. The data collected via the sensors may be organized and stored according to cardiac rhythm type. The organization of data according to cardiac rhythm type allows the patient's physician to be better able to monitor how the various parameters are related to the various cardiac rhythm types. In a typical embodiment, one or more of the sensors may be deployed on a single lead implanted in the heart.

Abstract: A biatrial and/or biventricular pacing system is used in a diagnostic context. By placing a pacing/sensing lead in three or four chambers of the heart, various conduction sequences can be determined and the originating chamber of various arrhythmias can be identified. This information is stored temporarily in the pacemaker until it is extracted for analysis.

Abstract: An ultrasound method and medical devices using same provide for various techniques of sampling blood flow velocity, e.g., at several sampling rates. To minimize the energy required for ultrasound monitoring, pulsed Doppler signal packages provided by a pulsed ultrasound circuit are switched in such a way that the repetition rate is the lowest possible and yet sufficiently high to be able to record the blood flow velocity within the heart. For example, an ultrasound circuit may be activated only within a part of the cardiac cycle designated as the Doppler Measurement Interval (DMI); the ultrasound circuit may be switched between an on state and an off state during the DMI; and/or the ultrasound circuit may also be switched on and off in different sampling modes: detection mode and measurement mode (e.g., using different sampling rates).

Abstract: A minimally invasive, implantable monitor and associated method for chronically monitoring a patient's hemodynamic function based on signals sensed by one or more acoustical sensors. The monitor may be implanted subcutaneously or submuscularly in relation to the heart to allow acoustic signals generated by heart or blood motion to be received by a passive or active acoustical sensor. Circuitry for filtering and amplifying and digitizing acoustical data is included, and sampled data may be continuously or intermittently written to a looping memory buffer. ECG electrodes and associated circuitry may be included to simultaneously record ECG data. Upon a manual or automatic trigger event acoustical and ECG data may be stored in long-term memory for future uploading to an external device. The external device may present acoustical data visually and acoustically with associated ECG data to allow interpretation of both electrical and mechanical heart function.

Abstract: The present invention uses a R-wave sensing algorithm that uniquely combines an automatic threshold adjustment method with a new noise rejection technique. This algorithm has significant advantages in avoiding the sensing of T-waves, P-waves, and noise/artifacts. Detecting the presence of noise bursts uses features that determine if an R-R interval adjacent to or within the noise signal is valid. Circuitry that discriminates noise signals from R-waves can use any one of several features including, but not limited to, the following: detection events occurring so close together that they are outside normal physiologic heart rates; frequency content that is wider than that of QRS complexes; amplitudes that are different than the adjacent or encompassing R-waves; and amplitudes that display greater than normal variability.