摘要:
Implantable electromedical device or loop recorders or ILRs that solve the problem of very low arrhythmia detection specificities in, i.e., high number of false positives, based on detection and analysis of external noise, specifically muscle noise surrounding the electromedical device. Embodiments generally employ active detection of lead or device movement that induces signal artifacts indicative of external noise. One or more embodiments may detect lead or device movement through use of a piezoelectric transducer, for example located proximally to the device or in the lead of the electromedical.
摘要:
Implantable electromedical device or loop recorders or ILRs that solve the problem of very low arrhythmia detection specificities in, i.e., high number of false positives, based on detection and analysis of external noise, specifically muscle noise surrounding the electromedical device. Embodiments generally employ active detection of lead or device movement that induces signal artifacts indicative of external noise. One or more embodiments may detect lead or device movement through use of a piezoelectric transducer, for example located proximally to the device or in the lead of the electromedical.
摘要:
Exemplary methods and apparatuses are disclosed that provide for determination of an atrio-ventricular delay on a beat-to-beat basis by determining a P-wave duration from electric signals corresponding to electric potentials in a heart, and determining the atrio-ventricular delay on a beat-to-beat basis such that the atrio-ventricular delay for an individual heart cycle depends on the P-wave duration of a same or an immediately preceding heart cycle.
摘要:
Exemplary methods and apparatuses are disclosed that provide for determination of an atrio-ventricular delay on a beat-to-beat basis by determining a P-wave duration from electric signals corresponding to electric potentials in a heart, and determining the atrio-ventricular delay on a beat-to-beat basis such that the atrio-ventricular delay for an individual heart cycle depends on the P-wave duration of a same or an immediately preceding heart cycle.
摘要:
A system, method and computer-readable storage medium are configured for the detection of electrical signals originating from a human or animal heart. In particular, for monitoring devices, it is desired to obtain electrical signals from a human or animal heart with electrical contacts at the body of an implantable medical device, hence without the need to implant electrical leads to the hearts. Hence, a method, a system and a computer-readable storage medium for detecting electrical signals originating from a human or animal heart is proposed. The method includes the steps of receiving electrical signals in at least two sensing channels, combining the electrical signals for forming a combined channel, extracting a template from the signals of the combined channel, comparing incoming electrical signals with the template, and depending from the result of the comparison, performing at least one of controlling one or more devices and signaling the result.
摘要:
Techniques are provided for estimating defibrillation impedance of an implantable cardioverter/defibrillator (ICD). Briefly, at least two low-voltage resistance values are measured at different voltages using a pair of stimulation electrodes connected to the ICD. High-voltage defibrillation impedance is then estimated by the ICD based on a weighted combination of the measured resistance values. In one example, a set of weight coefficients, calculated during an initial calibration procedure, are applied to the measured resistance values to produce the estimate of the high-voltage defibrillation impedance. The weight coefficients are updated whenever a defibrillation shock is delivered, based on actual defibrillation impedance values measured during the shock.
摘要:
An output stage for use in a therapeutic defibrillator enables practical use of specialized output waveforms optimized for cardiac defibrillation. A pulse-width modulated (PWM) switching amplifier, connected to a high voltage source capacitor and to one or more output bridges corresponding to different electrode placements, is adapted to operate with high efficiency, demonstrated at about 80%. The amplifier is capable of delivering a defibrillating electric shock to a heart in the form of a time-varying output voltage waveform of arbitrary shape. Efficiency improvement is accomplished through the use of a high voltage reservoir capacitor network configured to minimize a voltage differential between the high voltage reservoir and the output voltage. The switching amplifier features both step-up and step-down amplifier capability. A PWM control unit is positioned within the circuit so as to reduce complexity by eliminating a need for additional isolation circuitry.
摘要:
An implantable medical lead for coupling to an implantable pulse generator may be configured for improved safety. The lead may include: a first electrode; a second electrode in electrical communication with the first electrode; and an active circuit element in electrical communication with the first electrode and the second electrode. The active circuit element may be configured to change an impedance of the lead. The active circuit element may be configured to change the impedance of the lead in response to a pacing signal or a signal having opposite polarity to a pacing signal. A method of using an implantable medical lead for improved safety may include changing an impedance of an implantable medical lead from a relatively high impedance to a relatively low impedance and/or changing an impedance of an implantable medical lead from a relatively low impedance to a relatively high impedance.
摘要:
Systems and methods are provided for reducing heating within pacing/sensing leads of a pacemaker or implantable cardioverter-defibrillator that occurs due to induced loop currents during a magnetic resonance imaging (MRI) procedure, or in the presence of other sources of strong radio frequency (RF) fields. For example, bipolar coaxial leads are described herein wherein the ring conductor of the lead is disconnected from the ring electrode in response to detection of MRI fields so as to convert the ring conductor into an RF shield for shielding the inner tip conductor of the lead so as to reduce the strength of loop currents induced therein and hence reduce tip heating. Techniques are also described herein for selectively disconnecting the tip electrode of the lead during an MRI procedure, except during actual delivery of pacing pulses, so as to permit delivery of individual pacing pulses to pacemaker dependent patients during the MRI. Still other techniques describe the use of both RF shielding and tip switching.
摘要:
An implantable cardiac stimulation device and method provides reliable sensing of cardiac events to support cardiac pacing or fibrillation detection. The device comprises a sensing circuit that senses the cardiac events in accordance with a plurality of threshold characterizing parameters. A parameter control adjusts the threshold parameters responsive to the rate of the sensed cardiac events in a manner which precludes positive feedback to prevent continued oversensing, undersensing, or noise sensing.