Abstract: A nondefibrillating and nonfibrillation-inducing energy is delivered at a first internal thoracic location. A first resulting electrical signal is detected at a second internal thoracic location in or near a target region of a heart. A first defibrillation threshold is estimated using the nondefibrillating and nonfibrillation-inducing energy, the first resulting electrical signal, and a target electric field strength. The defibrillation threshold represents an energy that when delivered at the first internal thoracic location creates an electric field strength in the target region of the heart that meets or exceeds the target electric field strength.

Abstract: Advanced patient management systems include a unit for collecting data from a device associated with a patient, and a host in communication with the unit, the host identifying a time for the device to update data on the device. The system can identify a time for the device to update data associated with the device by developing a histogram of the availability of the device for interrogation. The system can also optimize processing loads for the system by developing a histogram of the time at which the caregiver is most likely to access the system to review the collected and processed data. Methods for optimizing device data update and processing times are also included.

Abstract: Cardiac monitoring and/or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed to detect, monitor, track and/or trend a patient's posture using cardiac activation sequence information. Devices and methods in accordance with the present invention involve sensing a plurality of composite cardiac signals using a plurality of implantable electrodes. A source separation is performed using the composite cardiac signals, which produces one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences. A change in a patient's posture is detected using the cardiac signal vectors. Further embodiments involve sensing the plurality of composite cardiac signals during the patient's predominant cardiac rhythm before detecting the change in the patient's posture.

Abstract: A system and method for classifying cardiac depolarization complexes in which waveforms of a depolarization complex are sensed by separate electrodes and correlated with template waveforms of a template depolarization complex. The system is particularly suitable for incorporation into a cardiac rhythm management device such as an implantable cardioverter/defibrillator or pacemaker in order to facilitate arrhythmia prediction and/or prevention.

Abstract: An apparatus and method for adjusting the performance of an implanted device based on data including contextual information. Contextual information, including operational and performance data concerning the implanted device as well as the patient with the implanted device, is stored by a portable electronic device. In one embodiment, the portable electronic device is adapted for battery operation and includes a personal digital assistant (PDA). The portable electronic device is adapted for use as an interface to conduct wireless communications with the implanted device. In one embodiment, the portable electronic device interfaces with a clinical programmer for use by a physician.

Abstract: A system and method for narrowcasting text messages to a plurality of cellular phones. The system and method allow a potential user to opt in to receive the text messages the user wants to receive. The potential user can opt in through a computer network based web page. Once the potential user sends a sign up request application to participate via the computer network, the user will receive a first text message containing an authorization code on their cell phone. The user enters the authorization code into the web page and sends the authorization code. Receipt of the authorization code back through the computer network will trigger the phone number of the potential user to be added to a list of authorized text message receivers. A narrowcaster then instructs the central computer to narrowcast text messages to the phone numbers on the list that have indicated they want to receive messages on a certain topic.

Abstract: Cardiac stimulation methods and systems provide for multiple pulse defibrillation, and involve sensing a fibrillation event, determining a fibrillation cycle length associated with the fibrillation event, and delivering a plurality of defibrillation pulses to treat the fibrillation event. Defibrillation pulses are delivered using a combination of subcutaneous non-intrathoracic electrodes. Delivery of each defibrillation waveform subsequent to a first defibrillation waveform is separated in time by a delay associated with the fibrillation cycle length. Delays between defibrillation waveform delivery may be associated with a percentage of the fibrillation cycle length.

Abstract: Cardiac lead implantation systems and methods including an electronics arrangement provided with a user interface and a coupler assembly. A coupler body is configured to detachably grasp a cardiac lead and couple with electrical contacts of the cardiac lead. A user interface includes an output indicative of sensed cardiac parameters, such as one or both of cardiac signal amplitude and lead electrode impedance, and may include an audio output device and/or a visual output device. Methods of lead implantation involve advancing a cardiac lead into proximity with a patient's heart, and contacting cardiac tissue with an electrode arrangement to locate a suitable implant location. Sensing of one or more cardiac parameters is accomplished and an audible representation of the sensed parameters is produced, the audible representation varying as the electrode arrangement is moved relative to the cardiac tissue.

Abstract: A technique for determining a patient's hematocrit by an electrical impedance measurement is described. An implantable device may be configured to utilize the technique in order to assess a cardiac patient's fluid status. In order to determine the hematocrit, the electrical impedance of the blood is measured and mapped by a mapping function to a corresponding hematocrit value.

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: A method of communicating text messages to a clinician as a reminder that certain program changes are to be made to a medical tissue stimulating device implanted in a patient. An external programmer capable of transmitting and receiving radio-frequency messages to and from the implant and visually displaying information is used to transmit text messages along with a text message initiation date and a text message termination date to the implanted device. These data are stored in a memory of the implanted device's microprocessor-based controller. Subsequently, at the time of a regularly scheduled patient follow-up, the implant may be interrogated by the external programmer and the text message read out and displayed if the time of the interrogation falls between the text message initiation date and its termination date.

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: Systems and methods for sleep state classification involve detecting conditions related to sleep, including at least one condition associated with rapid eye movement (REM) sleep. Additionally, a condition modulated by the sleep-wake status of the patient may be detected. A medical system that is partially or fully implantable incorporates sensors and circuitry for detecting and processing the sleep-related signals. A sleep state processor classifies the patient's sleep state based on the sleep-related signals. Sleep state classification may be used in connection with the delivery of sleep state appropriate therapy, diagnostic testing, or patient monitoring.