摘要:
A system and method for determining the optimal positioning of an implantable system for sensing physiologic signals within a body. According to a one embodiment of the system, electrodes are positioned on an external surface of a body, and an ECG monitoring device is used to measure cardiac signals between various pairs of the electrodes. One or more of the electrodes may be re-positioned until an electrode pair position and orientation is located that provides a maximum signal reading. This position and orientation may then be used as the position and orientation in which to implant a corresponding device.
摘要:
A system and method for obtaining a virtual physiologic voltage signal between a first predetermined point in a second selected point in the body is disclosed. At least three electrodes are used to measure two voltage signals S1 and S2 in a body. In one embodiment, the signal S1 is measured between a first electrode and a common electrode, and the signal S2 is measured between a second electrode and the common electrode. A selected point within the body may be chosen to define a pair of virtual electrodes existing between this selected point and the common electrode. An approximation of the voltage signal S as could be measured between electrodes positioned at these virtual electrode locations may be derived as a function of S1, S2, and &thgr;, wherein &thgr; is the angle between the directional vector U1 for the signal S1 and the directional vector U for the signal S. According to the inventive system and method, the signal value for S is also dependent on the distances between the electrode pairs, on the angle &bgr; between directional vectors U1 and U2, and on the distance between the virtual electrodes. The current invention may be utilized with electrodes that are positioned either externally on the surface of, or implanted within, a body. According to one aspect of the invention, a user may employ a user interface to select the values of &thgr;, &bgr;, and the electrode spacings. Alternatively, ones of these parameters may be predetermined by the system. In another embodiment, the system could derive the signal S over a predetermined range of values for the angle &thgr;. The system may then select the angle of &thgr; resulting in the derived signal S that exhibits a desired waveform morphology.
摘要:
A method and apparatus for detecting atrial arrhythmias include acquiring a cardiac signal comprising R-waves. Differences between pairs of consecutive R-R intervals occurring during a first time interval are computed from the cardiac signal. An atrial arrhythmia is detected subsequent to the first time interval in response to the computed differences. Storage of the cardiac signal is triggered in response to the atrial arrhythmia detection.
摘要:
A physiological monitoring or therapy delivery system includes autonomous, wirelessly linked, implantable devices located at different areas to sense physiologic signals and deliver therapy. At least one of the implantable devices can trigger synchronized action (e.g. data capture or therapy delivery) by other implantable devices via a telemetry link.
摘要:
An implantable medical device (IMD) applies a sensor self-test when a sensing device generates a sensor signal indicating an event, or when the sensor is used to validate an event detected by another device. The event may be based on a sensed condition that triggers an operational adjustment, such as a therapy or diagnostic adjustment within the IMD. A sensor self-test verifies that an implantable sensing device is functional, and can be performed with or without activating the sensor. Activating the sensor may involve, application of an electrical input signal that causes the sensor to generate an output signal. Alternatively, the sensor self-test may be performed without activating the sensor by analyzing the continuity of a signal path between the sensor and sensor interface circuitry. In either case, a sensor self-test verifies proper operation so that operational adjustments can be made with greater confidence.
摘要:
A method and apparatus for detecting atrial arrhythmias include acquiring a cardiac signal comprising R-waves. Differences between pairs of consecutive R-R intervals occurring during a first time interval are computed from the cardiac signal. An atrial arrhythmia is detected subsequent to the first time interval in response to the computed differences. Storage of the cardiac signal is triggered in response to the atrial arrhythmia detection.
摘要:
A physiological monitoring or therapy delivery system includes autonomous, wirelessly linked, implantable devices located at different areas to sense physiologic signals and deliver therapy. At least one of the implantable devices can trigger synchronized action (e.g. data capture or therapy delivery) by other implantable devices via a telemetry link.
摘要:
Triggers and noise should be available as information in recorded electrograms in memories of implantable medical devices. Particularly where the recording of electrogram data is done in the far field, there will be considerable noise and the interpretation of ECG's reproduced from such recorded data will benefit from the storing of information regarding contemporaneous noise. By storing contemporaneous trigger data and noise data directly in the ECG data, recordings of the ECG data become more useful for physician use when played back through an external display system with minimal loss of ECG data, since out of range values are employed for the noise and trigger information and this non-ECG data is limited in size to no longer than individual point values of the ECG signal.
摘要:
A system for recording trigger events and noise in conjunction with the recording of physiological signals is provided for use in an implantable medical device. In one embodiment, recorded trigger and noise data is provided for display to a physician along with reconstructed ECG data to facilitate interpretation of the ECG signal. In one embodiment, digitized ECG samples that are outside of a predetermined range are discarded during the sampling process so that one or more ranges of encoded values are available for use in encoding noise and trigger information. This non-physiologic data may be limited in size to individual point values of the ECG signal.
摘要:
An implantable medical device which preferably has a segmented looping memory for storing triggered physiologic events also has autotriggers to record the ECGs and any other relevant physiologic signals occurring during triggering events. The problem is that in the far field R-wave sensing is difficult because of noise. Denial and extensible accommodation periods are introduced into the R-wave sensing registration for triggering data storage. If the event is sensed during an accommodation period the sense will not add an R-wave sense to the trigger's count of R-waves. It may cause resetting of the trigger count in some circumstnaces. Typical triggering events may include arrhythmia's and syncopal events. Preferably the device can function without a microprocessor. An outside device or other patient activated manual trigger may be included. Auto triggers and manually set triggers may be of different sizes. Electrode spacing can be critical. Additional sensors may be provided to the device. Preferred communications with the device is through telemetry such as is used for pacemakers and other implanted devices.