Techniques and devices for implementing the techniques for adjusting atrial arrhythmia detection based on analysis of one or more P-wave sensing windows associated with one or more R-waves. An implantable medical device may determine signal characteristics of the cardiac signal within the P-wave sensing window, determine whether the cardiac signal within the sensing window corresponds to a P-wave based on the determined signal characteristics, determine a signal to noise ratio of the cardiac signal within the sensing window, update the arrhythmia score when the P-wave is identified in the sensing window and the determined signal to noise ratio satisfies a signal to noise threshold.

In some examples, a medical device system includes an electrode. The medical device system may include impedance measurement circuitry coupled to the electrode, the impedance measurement circuitry may be configured to generate an impedance signal indicating impedance proximate to the electrode. The medical device system may include processing circuitry that may be configured to identify a first component of the impedance signal. The first component of the impedance signal may be correlated to a cardiac event. The processing circuitry may be configured to determine that the cardiac event occurred based on the identification of the first component of the impedance signal.

Apparatuses, systems and methods are provided that may include a system for patient monitoring and defibrillation. The system may include at least two defibrillation electrodes. The system may further include a first unit for physiological monitoring of a patient, including ECG monitoring circuitry for monitoring ECG of the patient. The first unit may store CPR chest compression data. The system may further include a second unit, separate from the first unit, which may communicatively couple with the first unit, for providing defibrillation pulses to the patient. The second unit may include a processor, communicatively coupled with the at least two defibrillation electrodes, for providing defibrillation pulses to the patient via the at least two defibrillation electrodes.

A system for providing remote assistance to a caregiver during a medical event includes a computer tablet with a transmitter/receiver to communicably couple the tablet with a remote computing system associated with central caregivers, physiological sensors for collecting patient information, and a defibrillator configured to couple to the sensors and including a transmitter/receiver to communicably couple the defibrillator and tablet, and a processor to receive the patient information from the sensors, provide the patient information for display, and communicate the patient information to the tablet, the tablet being configured to generate a user alert for communications with the remote system based on a signal indicating that resuscitative treatment of the victim is being administered, the signal including the patient information received from the sensors, and the user alert including a request for a confirmation to initiate communications with the remote system, and, in response, establish communications with the remote system.

A wearable medical includes a walking detector module with a motion sensor that is configured to detect when the patient is walking or running. In embodiments, a parameter (referred to herein as a “Bouncy” parameter) is determined from Y-axis acceleration measurements. In some embodiments, the Bouncy parameter is a measurement of the AC component of the Y-axis accelerometer signal. This detection can be used by the medical device to determine how and/or whether to provide treatment to the patient wearing the medical device. For example, when used in a WCD, the walking detector can prevent “false alarms” because a walking patient is generally conscious and not in need of a shock.

An example medical device includes a plurality of electrodes, therapy delivery circuitry, and processing circuitry configured to control the therapy delivery circuitry to deliver electrical stimulation to an intercostal nerve of a patient via at least two of the plurality of electrodes, wherein the electrical stimulation is delivered with stimulation parameters configured to suppress ventricular tachyarrhythmia of the patient, wherein the stimulation parameters comprise a stimulation frequency less than or equal to 40 hertz (Hz).

A patient-worn arrhythmia monitoring and treatment device includes a pair of therapy electrodes and at least one pair of sensing electrodes disposed proximate to the skin and configured to continually sense at least one ECG signal of the patient over an extended period of time. The device includes a therapy delivery circuit coupled to the pair of therapy electrodes and configured to deliver one or more therapeutic pulses. A controller coupled to therapy delivery circuit is configured to analyze the at least one ECG signal and detect one or more treatable arrhythmias and cause the therapy delivery circuit to deliver the one or more therapeutic pulses to the patient. At least one of the one or more therapeutic pulses is formed as a biphasic waveform delivering within 15 percent of 360 J of energy to a patient body having a transthoracic impedance from about 20 to about 200 ohms.

Techniques and devices for implementing the techniques for adjusting atrial arrhythmia detection based on analysis of one or more P-wave sensing windows associated with one or more R-waves. An implantable medical device may determine signal characteristics of the cardiac signal within the P-wave sensing window, determine whether the cardiac signal within the sensing window corresponds to a P-wave based on the determined signal characteristics, determine a signal to noise ratio of the cardiac signal within the sensing window, update the arrhythmia score when the P-wave is identified in the sensing window and the determined signal to noise ratio satisfies a signal to noise threshold.

An extra-cardiovascular implantable cardioverter defibrillator (ICD) having a low voltage therapy module and a high voltage therapy module is configured to select, by a control module of the ICD, a pacing output configuration from at least a low-voltage pacing output configuration of the low voltage therapy module and a high-voltage pacing output configuration of the high voltage therapy module. The high voltage therapy module includes a high voltage capacitor having a first capacitance and the low voltage therapy module includes a plurality of low voltage capacitors each having up to a second capacitance that is less than the first capacitance. The ICD control module controls a respective one of the low voltage therapy module or the high voltage therapy module to deliver extra-cardiovascular pacing pulses in the selected pacing output configuration via extra-cardiovascular electrodes coupled to the ICD.

A medical device is configured to sense first ventricular event signals from a first cardiac electrical signal and sense second ventricular event signals from a second cardiac electrical signal. The medical device is configured to determine sensed event data in response to the first ventricular event signals and the second ventricular event signals. The medical device may select one of the first cardiac electrical signal or the second cardiac electrical signal for providing input for tachyarrhythmia detection based on the sensed event data.