Abstract: An implantable medical device performs impedance measurement and demodulation, such as for obtaining lead impedance measurements, or thoracic impedance measurements, such as for extracting respiration, cardiac stroke, or fluid status information. A 4-point FIR filter demodulator can be used to demodulate a two-phase current excitation waveform. The demodulator can also be used to measure noise for triggering a noise response. Among other things, an increased excitation current level can be used when noise is deemed to be present.

Abstract: An implantable medical device can include a Hall effect sensor. The Hall effect sensor can include a first pair of electrical contacts and a second pair of electrical contacts. In an example, the Hall effect sensor can be configured to sense a magnetic field and can be configured to provide a voltage corresponding to a magnitude of the sensed magnetic field.

Abstract: This document discusses, among other things, an apparatus comprising, a plurality of electrodes configured to deliver defibrillation countershock energy to a subject, an impedance measurement circuit communicatively coupled to the electrodes and configured to measure the impedance between any two of the electrodes using a non-stimulating excitation signal, and a controller communicatively coupled to the impedance measurement circuit and configured to calculate the impedance of a shock vector, wherein the shock vector includes a first electrode and a second electrode electrically connected together, and a third electrode, and wherein the controller calculates the impedance using measured impedances between the three electrodes when none of them are electrically connected.

Abstract: An implantable medical device can include a Hall effect sensor. The Hall effect sensor can include a first pair of electrical contacts and a second pair of electrical contacts. In an example, the Hall effect sensor can be configured to sense a magnetic field and can be configured to provide a voltage corresponding to a magnitude of the sensed magnetic field.

Abstract: An operating mode of an implantable medical device can be selected using at least one of a current or a voltage provided in response to a magnetic field sensed using a Hall effect sensor.

Abstract: An implantable medical device performs impedance measurement and demodulation, such as for obtaining lead impedance measurements, or thoracic impedance measurements, such as for extracting respiration, cardiac stroke, or fluid status information. A 4-point FIR filter demodulator can be used to demodulate a two-phase current excitation waveform. The demodulator can also be used to measure noise for triggering a noise response. Among other things, an increased excitation current level can be used when noise is deemed to be present.

Abstract: An operating mode of an implantable medical device can be selected using at least one of a current or a voltage provided in response to a magnetic field sensed using a Hall effect sensor.

Abstract: This document discusses, among other things, an apparatus comprising, a plurality of electrodes configured to deliver defibrillation countershock energy to a subject, an impedance measurement circuit communicatively coupled to the electrodes and configured to measure the impedance between any two of the electrodes using a non-stimulating excitation signal, and a controller communicatively coupled to the impedance measurement circuit and configured to calculate the impedance of a shock vector, wherein the shock vector includes a first electrode and a second electrode electrically connected together, and a third electrode, and wherein the controller calculates the impedance using measured impedances between the three electrodes when none of them are electrically connected.