摘要:
A method and apparatus for providing an enhanced capability of detecting and gathering electrical cardiac signals via an array of relatively closely spaced subcutaneous electrodes (located on the body of an implanted device) which may be employed with suitable switching circuits, signal processors, and memory to process the electrical cardiac signals between any selected pair or pairs of the electrode array in order to provide a leadless, orientation insensitive means for receiving the electrical signal from the heart. This far-field EGM may be used to provide storage and analysis of arrhythmic events and to provide control signals for the delivery of various therapies including pacing, cardioversion and defibrillation therapies as well as the delivery of antiarrhythmic drugs, and, in the pacing context, to effect capture detection and automatic stimulation threshold adaption, recording of PMT episodes, measurement of refractory periods in order to set timing windows for antitachy pacing therapies, and as a control signal for use in adjusting pacing rate to physiologic demand.
摘要:
An improved turning point system and method for performing data compression is disclosed. The system improves the conventional turning point compression method by selecting a predetermined number of the “best” turning points in the sample window including data samples X0 and XN. From this sample-window, ones of the data samples X1 through X(N−1) will be identified as turning points using a selected one of a disclosed set of turning point detection methods. In one embodiment, a turning point is identified by determining that the slopes in the lines interconnecting adjacent data points have different polarities. In an alternative embodiment, a data sample XM is considered a turning point if the slope of the line between the data samples XM and X(M+1) has a different polarity as compared to the slope of the last waveform segment that was encountered that did not have a slope of zero. According to one mechanism, amplitude thresholding is used to detect whether an identified turning point is likely the result of noise such that the turning point status of the data sample should be disregarded. After data samples are identified as turning points, ones of the identified turning points are identified as the “best” turning points to be selected for retention. The best turning points may be identified by determining which waveform segment included within a sample window has the largest change of amplitude. An alternative embodiment detects which of the turning points has the greatest signal amplitude compared to a reference value. Yet another embodiment selects as the best turning point that point having an amplitude that differs the most from the amplitude of the first data sample in the sample window. Still other embodiments retain the turning point having an amplitude which is more positive, or alternatively, more negative, than the other data samples. According to one aspect of the invention, the compression ratio varies based on the frequency of the input waveform. In another embodiment, position data is retained to indicate the relative position of retained data samples as compared to the position of other retained data samples. This position data may be calculated at a frequency that is less than the frequency of the sampled data.
摘要:
A minimally invasive implant, means for insertion, and description of how to most efficiently use it are described n several embodiments. This implant preferably has a segmented looping memory for storing triggered physiologic events. Preferred events for setting autotriggers to record physiologic signals occurring during events include arrhythmias and syncopal events. Preferably the device can function without a microprocessor. An outside device or other patient activated manual trigger is included. Auto triggers and manually set triggers may be of different sizes. The preferred physiologic events are ECG signals. 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.
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:
A system, comprising a sterilizable package; an implantable medical device placed inside the sterilizable package; and an electrical interface electrically coupled to the implantable medical device and extending from inside the sterilizable package to outside the sterilizable package. In various embodiments, the interface may include package contacts electrically coupled to electrode terminals on the implantable medical device, patient terminals and conductors extending between the package contacts and the patient terminals.
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:
An implantable dual transducer apparatus for use with an implantable medical device and control method are disclosed. The dual transducer assembly includes two physiologic sensors coupled to the medical device via a pair of lead conductors. Switching circuitry is controlled by the medical device to selectively activate and deactivate the two physiologic sensors by application of a supply voltage of an appropriate polarity. Each sensor of the dual transducer assembly is connected to the pair of lead conductors through a respective power switch. In response to the polarity of the supply voltage applied to the lead conductors, the power switches activate or deactivate their respective sensor in an alternating manner. Selective activation of one of the sensor while concurrently deactivating the other sensor of the dual transducer assembly provides for reduced power consumption and reliable communication of sensor data and other information transmitted over the pair of lead conductors. The power switches may be constructed using diodes, including discrete or substrate diodes, or transistors, such as n-channel and p-channel transistors. A wide variety of physiologic sensors may be incorporated into the dual transducer assembly.
摘要:
A percutaneous delivery tool may be used to implant a medical device, for example, within a subcutaneous space. The percutaneous delivery tool may include a handle, first and second attachment members, and first and second connecting members connecting the attachment members to the handle. In some examples, the first and second attachment members are configured to receive the medical device such that the medical device is positioned between the attachment members. In some additional examples, the first and second connecting members are angled with respect to the handle, the first connecting member is angled with respect to the first attachment member, and the second connecting member is angled with respect to the second attachment member.
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 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.