摘要:
A method and device for delivering a pulse waveform to a target site of a patient that includes an energy storage device storing electrical energy, and a plurality of electrodes electrically coupled to the energy storage device. Control circuitry, coupled to a plurality of switching elements coupled to the plurality of electrodes, selectively switches the plurality of switching elements between a first state and a second state to direct discharge of the stored energy to be simultaneously output at selected electrodes of the plurality of electrodes to generate discrete sequential resultant output pulses across multiple pathways, the discrete sequential resultant output pulses generating a multi-directional waveform at the target site.
摘要:
Techniques for estimating the temporal refractory period of a heart, for adjusting a parameter for delivery of extra-systolic stimulation (ESS) therapy and for detecting an arrhythmia during delivery of ESS therapy are disclosed. In some embodiments, probe pulses are periodically delivered to estimate the location of the end boundary of the refractory period, and accordingly estimate its length. In some embodiments, the parameter is adjusted based on estimated length of the refractory period. For example, an extra-systolic interval (ESI) for delivery of ESS is adjusted to be a fixed interval longer than estimated lengths of the refractory period. In other embodiments, the parameter is adjusted based on a measured delay (or latency) between delivery of an ESS pulse and detection of an evoked response resulting from the pulse. In some embodiments, delays between delivery of an ESS pulse and detection of a subsequent depolarization are monitored to detect an arrhythmia.
摘要:
A medical device including a housing, multiple sensing elements positioned along the housing for use in sensing a physiological signal, and an accelerometer is configured to detect a change in device orientation relative to patient anatomy. The device measures a first accelerometer signal corresponding to a first orientation of the housing with respect to a patient position. The device detects a second orientation of the housing different than the first orientation in response to a comparison between the first accelerometer signal and a next accelerometer signal.
摘要:
The present invention outlines structures and methods for delivering a controllable amount of energy to a patient by automatically compensating for the load impedance detected by an implantable-cardioverter defibrillator (ICD). The invention employs high speed, switching power converter technology for the efficient generation of high energy, arbitrarywaveforms. Unlike a linear amplifier, switching power converters deliver high-energy waveforms with an efficiency that is independent of the size and amplitude of the desired waveform. An ICD that uses a switching power converter to deliver the desired energy to the patient stores the energy to be delivered in a storage capacitor. The converter then transforms this energy into an arbitrarily shaped output voltage-controlled or current-controlled waveform by switching the storage capacitor in and out of the output circuit at a high rate of speed. Preferably, the waveform comprises a ramp-type waveform.
摘要:
A method and apparatus for actively determining a coupling interval corresponding to a cardiac vulnerable zone associated with a therapy of an implantable medical device that includes a timing and control unit delivering, via electrodes of a plurality of electrodes, a first pulse train and a first pulse signal at a predetermined time interval from delivery of a last pulse of the first pulse train. A sensor determines an evoked response corresponding to the first pulse signal, and a microprocessor compares the evoked response to a prior determined evoked response and sets the coupling interval equal to the predetermined time interval in response to the evoked response having increased by a first predetermined amount, and reduces the predetermined time interval by a second predetermined amount in response to the evoked response not having increased by the first predetermined amount.
摘要:
A method of operating a cardiac pacing device that optimizes the mechanical heart rate using coordinated potentiation therapy while maximizing the opportunity for intrinsic AV conduction to occur. The method may include adjusting the timing of extra stimulus intervals during coupled or paired pacing to promote AV conduction and to effect changes in rate according to certain embodiments of the invention. Other embodiments may include adjusting the atrial pacing rate to achieve a desired target rate consistent with AV conduction. A mode switch to a dual-chamber pacing mode may be provided according to certain embodiments of the invention to ensure a ventricular rate that meets or exceeds a minimum mechanical rate.
摘要:
A method and apparatus for validating a cardiac pacing pulse train preceding a T-shock. Validation of the pacing pulse train includes verifying capture of at least the last pacing pulse of the pulse train and verifying that intrinsic ventricular events are not sensed during a pacing train interval that includes at least the interval between the last pacing pulse and a scheduled T-shock delivery. Capture verification may include sensing an event during an ER sensing window, morphological analysis of a sensed event, and analysis of the temporal relationship between sensed events occurring on different EGM sources. The scheduled T-shock is delivered in response to a valid pacing pulse train. A response to an invalid pacing pulse train may include any of an invalid pacing train notification, withholding a scheduled T-shock, extension of the pacing train, repeating the pacing train, or adjusting the pacing pulse train parameters.