A medical device, such as an extra-cardiovascular implantable cardioverter defibrillator (ICD), senses R-waves from a first cardiac electrical signal by a first sensing channel and stores a time segment of a second cardiac electrical signal acquired by a second sensing channel in response to each sensed R-wave. The ICD determines morphology match scores from the stored time segments of the second cardiac electrical signal and, based on the morphology match scores, withholds detection of a tachyarrhythmia episode. In some examples, the ICD detects T-wave oversensing based on the morphology match scores and withholds detection of a tachyarrhythmia episode in response to detecting the T-wave oversensing.

A system and method for ECG data classification for use in facilitating diagnosis of cardiac rhythm disorders is provided. ECG data is obtained via an electrocardiography monitor shaped for placement on a patient's chest. The ECG data is divided into segments and noise detection analysis is applied to the ECG data segments. A noise classification or a valid classification is assigned to each segment of the ECG data. At least one ECG data segment assigned the noise classification and that includes ECG data that corresponds with feedback from the patient via the electrocardiography monitor is identified. The ECG data that corresponds with the patient feedback is removed from the identified ECG data segment with the noise classification. The ECG data segments assigned the noise classification are removed from further analysis.

A system and method for the safe delivery of treatment energy to a patient, which includes verification of system integrity before, during, or after the delivery of treatment energy and provides several mechanisms for rapid termination of the delivery of potentially harmful energy to the patient when a fault condition in the device and/or system is identified. The system may include an energy generator having processing circuitry to determine if there is a fault condition in the system and to automatically terminate a delivery of treatment energy when the processing circuitry determines there is a fault condition. The method may generally include performing a series of pre-checks, synchronizing a treatment energy delivery to the proper segment of the heart's depolarization pattern, configuring the system for treatment energy delivery, delivering the treatment energy, and performing post-treatment evaluation.

Methods and systems for use of the Q-wave to R-wave interval to guide placement of a leadless cardiac pacemaker are disclosed. An implant delivery device is equipped with sensing electrodes to sense R-wave onset in a ventricle of a patient's heart to allow placement at a location of last or latest onset of the R-wave. Guidance tools are provided to assist in determination of the Q-wave to R-wave interval during implantation. For a chronic system, a cooperative approach is disclosed in which an implantable medical device and a leadless cardiac pacemaker exchange data to determine Q-wave to R-wave intervals and enhance cardiac resynchronization therapy delivery by the leadless cardiac pacemaker.

Methods and devices adapted for cardiac signal analysis. A method or device has accessible to it more than one approach to cardiac cycle rate analysis and is adapted to monitor sensing signal quality. In response to an apparent reduction in signal quality or other trigger, the method or device checks whether an arrhythmia or an actual drop in signal quality is occurring prior to modifying sensing configurations or parameters.

A system and method for facilitating a cardiac rhythm disorder diagnosis with the aid of a digital computer is provided. Cutaneous action potentials of a patient are recorded over a set period of time as ECG data and a difference between recording times of successive pairs of R-wave peaks are recorded as R-R intervals. A heart rate is associated with each time difference. An R-R interval plot of the ECG data is generated. A presence of a cardiac event is displayed by presenting a presence of sinus tachycardia or a presence of bradycardia via the R-R interval plot.

A pacemaker having a motion sensor delivers atrial-synchronized ventricular pacing by detecting events from a signal produced by the motion sensor and delivering ventricular pacing pulses at a rate that tracks the rate of the detected events. The pacemaker is configured to confirm atrial tracking of the ventricular pacing pulses by determining if detected events from the motion sensor signal are atrial events. The pacemaker is configured to adjust a control parameter used for detecting events from the motion sensor signal if atrial tracking is not confirmed.

A method and device for detecting a sleep state by heart-rate and movement data. By neural network software, a sleep state is detected using as input data movement data (move_count) and data derived from heart-rate data and/or data derived from inter-beat interval data such as (MAD) and respiration data (RESP). At least a portion of the variables (HRD, MHR, MAD, Resp, GRD) derived from the heart-rate data/inter-beat interval data are further modified by one, most preferably 2-4, artificial average functions and the cumulative sleep time is one input datum.

A method for determining the hydration status of a person prompts the person to breathe while in a first postural position during which the method measures a first heart rate variability (HRV) value. The person is prompted to change to a second postural position, and the method measures a second HRV value. A difference between the first HRV value and the second HRV value is a daily score. The daily score is subtracted from a baseline to obtain a hydration score. In certain embodiments, the person is requested to respond to a plurality of subjective questions. The method processes the subjective responses and the daily score to determine whether the person is adequately hydrated. In certain embodiments of the method, the person is requested to identify the color of the person's urine. The identified color is processed with the daily score and the subjective responses to determine hydration.

A computer-implemented method for contact photoplethysmography, abbreviated contact PPG, comprises obtaining during a time interval plural PPG signals for sub-regions of a lens or video frame; and combining the plural PPG signals to thereby obtain a multi-region PPG signal.