Abstract: An implantable medical device such as an implantable pacemaker or implantable cardioverter/defibrillator includes a programmable sensing circuit providing for sensing of a signal approximating a surface electrocardiogram (ECG) through implanted electrodes. With various electrode configurations, signals approximating various standard surface ECG signals are acquired without the need for attaching electrodes with cables onto the skin. The various electrode configurations include, but are not limited to, various combinations of intracardiac pacing electrodes, portions of the implantable medical device contacting tissue, and electrodes incorporated onto the surface of the implantable medical device.

Abstract: Methods and electronic tools for imaging a chest region of a patient and communicating with a heart stimulation device used by the patient are disclosed. The electronic tool may include a communications device for two-way data transmission of signals encoded with information to and from the heart stimulation device. The tool may also include an imaging device for radiating energy onto the chest of the patient and receiving energy as it is reflected from the chest region to produce an image signal. The tool may include a display screen for showing an image of the chest area and/or the information received from the heart stimulation device. The tool may also include a processor for formulating and/or analyzing information sent to and/or received from the heart stimulation device. One method of using the electronic tool includes analyzing the image signal and/or received information to provide instructions to the heart stimulation device.

Abstract: Devices and methods for sleep detection involve the use of an adjustable threshold for detecting sleep onset and termination. A method for detecting sleep includes adjusting a sleep threshold associated with a first sleep-related signal using a second sleep-related signal. The first sleep-related signal is compared to the adjusted threshold and sleep is detected based on the comparison. The sleep-related signals may be derived from implantable or external sensors. Additional sleep-related signals may be used to confirm the sleep condition. A sleep detector device implementing a sleep detection method may be a component of an implantable pulse generator such as a pacemaker or defibrillator.

Abstract: The presence of disordered breathing is detected using an implantable medical device. A cardiac condition is detected that is indicative of the patient's cardiac status. Based on the presence of disordered breathing and the cardiac condition, the patient is identified as suitable for a cardiac resynchronization therapy.

Abstract: This document discusses, among other things, systems, devices, and methods measure an impedance and, in response, adjust an atrioventricular (AV) delay or other cardiac resynchronization therapy (CRT) parameter that synchronizes left and right ventricular contractions. A first example uses parameterizes a first ventricular volume against a second ventricular volume during a cardiac cycle, using a loop area to create a synchronization fraction (SF). The CRT parameter is adjusted in closed-loop fashion to increase the SF. A second example measures a septal-freewall phase difference (PD), and adjusts a CRT parameter to decrease the PD. A third example measures a peak-to-peak volume or maximum rate of change in ventricular volume, and adjusts a CRT parameter to increase the peak-to-peak volume or maximum rate of change in the ventricular volume.

Abstract: A method and system are described for determining an optimum atrioventricular delay (AVD) interval and/or ventriculo-ventricular delay (VVD) intervals for delivering ventricular resynchronization pacing in an atrial tracking or atrial sequential pacing mode. Evoked response electrograms recorded at different AVD and VVD intervals are used to determine the extent of paced and intrinsic activation.

Abstract: Calibration of adaptive-rate pacing by a cardiac rhythm management system using an intrinsic chronotropic response. The cardiac rhythm management system may include an adaptive-rate pacing device. The adaptive-rate pacing device may include an adaptive-rate sensor module for measuring an activity level of the individual. A monitor module may be coupled to the adaptive-rate sensor module, the monitor module monitoring an intrinsic chronotropic response. A calculator module may be coupled to the monitor module, the calculator module calculating a calibrated parameter for the adaptive-rate pacing device based on the intrinsic chronotropic response. An adjuster module may be coupled to the calculator module, wherein the adjuster module adjusts the adaptive-rate pacing device based on the calibrated parameter. The parameters of the adaptive-rate pacing device adjusted by the adjuster module may include a sensor rate target, a maximum sensor rate, and a response factor.

Abstract: Methods and systems for classifying cardiac responses to pacing stimulation and/or preventing retrograde cardiac conduction are described. Following delivery of a pacing pulse to an atrium of the patient's heart during a cardiac cycle, the system senses in the atrium for a retrograde P-wave. The system classifies the atrial response to the pacing pulse based on detection of the retrograde P-wave. The system may also sense for an atrial evoked response and utilize the atrial evoked response in classifying the cardiac pacing response.

Abstract: This document discusses, among other things, a combination pacer/defibrillator that is tailored for bradycardia patients. In one example, its shock-delivery specificity exceeds its sensitivity to shockable ventricular tachyarrhythmias. In another example, its specificity exceeds 95%, or 99%, or even 99.5%. Sensitivity is programmed to a high desired sensitivity value, but only if it can be done without decreasing the specificity below the desired specificity threshold value. This can be conceptualized as “avoiding at all costs” delivering false shocks, even at the expense of failing to deliver a shock to a treatable ventricular tachyarrhythmia. Specificity enhancements include, among other things, inhibiting shock delivery when the patient is breathing or not supine, using multiple channels or a high rate VT/VF detection threshold.

Abstract: A maximum pacing rate limiter for use in adaptive rate pacing in conjunction with a cardiac rhythm management system for a heart. The maximum pacing rate limiter may function to measure an interval, termed the ERT interval, between a paced ventricular evoked response and a T-wave. The maximum pacing rate limiter may further function to maintain the ERT interval at less than a certain percentage of the total cardiac cycle. In one disclosed embodiment, a maximum pacing rate limiter calculates an ERT rate based on the detected paced ventricular evoked response and the T-wave, and the pacing rate limiter module further communicates the minimum of the ERT rate and an adaptive-rate sensor indicated rate to a pacemaker.

Abstract: Cardiac monitoring and/or stimulation methods and systems provide monitoring, defibrillation and/or pacing therapies. A signal processor receives a plurality of composite signals associated with a plurality of sources, separates a signal using a source separation algorithm, and identifies a cardiac signal using a selected vector. The signal processor may iteratively separate signals from the plurality of composite signals until the cardiac signal is identified. The selected vector may be updated if desired or necessary. A method of signal separation involves detecting a plurality of composite signals at a plurality of locations, separating a signal using source separation, and selecting a vector that provides a cardiac signal. The separation may include a principal component analysis and/or an independent component analysis.

Abstract: An implantable pacemaker is provided with a far-field sensing channel which requires a reduced refractory period during the time when pacing pulses are delivered as compared with sensing channels using intra-cardiac electrodes. The far-field sensing channel may use the conductive housing of the implantable device or can and an indifferent electrode mounted on the device header as the electrodes for its differential inputs. Such a far-field sensing channel is able to sense activity occurring in either the atria or the ventricles for the purposes of arrhythmia detection and/or capture verification.

Abstract: This document discusses, among other things, systems and methods that detect hypotension based on a measurement of thoracic impedance. It also provides an alert, a logging, or a therapy to treat the hypotension. Examples of anti-hypotension therapies include, among other things, pacing therapy, neural stimulation therapy, drug infusion therapy, or gene therapy.

Abstract: A cardiac rhythm management device predicts defibrillation thresholds without any need to apply defibrillation shocks or subjecting the patient to fibrillation. Intravascular defibrillation electrodes are implanted in a heart. By applying a small test energy, an electric field near one of the defibrillation electrodes is determined by measuring a voltage at a sensing electrode offset from the defibrillation electrode by a known distance. A desired minimum value of electric field at the heart periphery is established. A distance between a defibrillation electrodes and the heart periphery is measured, either fluoroscopically or by measuring a voltage at an electrode at or near the heart periphery. Using the measured electric field and the measured distance to the periphery of the heart, the defibrillation energy needed to obtain the desired electric field at the heart periphery is estimated. In an example, the device also includes a defibrillation shock circuit and a stimulation circuit.

Abstract: An implantable medical device such as a cardiac pacemaker or implantable cardioverter/defibrillator with the capability of receiving communications in the form of speech spoken by the patient. An acoustic transducer is incorporated within the device which along with associated filtering circuitry enables the voice communication to be used to affect the operation of the device or recorded for later playback.

Abstract: An implantable medical device such as an implantable pacemaker or implantable cardioverter/defibrillator includes a programmable sensing circuit providing for sensing of a signal approximating a surface electrocardiogram (ECG) through implanted electrodes. With various electrode configurations, signals approximating various standard surface ECG signals are acquired without the need for attaching electrodes with cables onto the skin. The various electrode configurations include, but are not limited to, various combinations of intracardiac pacing electrodes, portions of the implantable medical device contacting tissue, and electrodes incorporated onto the surface of the implantable medical device.

Abstract: This document describes, among other things, a body having at least one acoustically detectable property that changes in response to a change in a physiological condition, such as ischemia. The body is positioned with respect to a desired tissue region. At least one acoustic transducer is used to acoustically detect a change in physical property. In one example, the body is pH sensitive and/or ion selective. A shape or dimension of the body changes in response to pH and/or ionic concentration changes resulting from a change in an ischemia state. An indication of the physiological condition is provided to a user.

Abstract: A sleep quality assessment approach involves collecting data based on detected physiological or non-physiological patient conditions. At least one of detecting patient conditions and collecting data is performed using an implantable device. Sleep quality may be evaluated using the collected data by an imlantable or patient-external sleep quality processor. One approach to sleep quality evaluation involves computing one or more summary metrics based on occurrences of movement disorders or breathing disorders during sleep.

Abstract: An approach to providing disordered breathing therapy includes providing therapy based on a prediction of disordered breathing. One or more patient conditions are detected and used to predict disordered breathing. Therapy is delivered to mitigate the predicted disordered breathing. The disordered breathing therapy may be adapted to enhance therapy efficacy and/or to reduce the impact of the therapy to the patient.

Abstract: An approach to providing disordered breathing therapy includes detecting disordered breathing and adapting a therapy to mitigate the disordered breathing. The therapy may be adapted to enhance therapy effectiveness, to provide therapy that reduces an impact of the therapy on the patient, or to achieve other therapeutic goals. Cardiac electrical therapy to mitigate the disordered breathing may include various cardiac pacing regimens and/or delivery of non-excitatory electrical stimulation to the heart.