Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In some examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. Several examples emphasize the use of morphology analysis using correlation to static templates and/or inter-event correlation analysis.

An implantable neurostimulator-implemented method for managing tachyarrhythmias through vagus nerve stimulation is provided. An implantable neurostimulator, including a pulse generator, is configured to deliver electrical therapeutic stimulation in a manner that results in creation and propagation (in both afferent and efferent directions) of action potentials within neuronal fibers of a patient's cervical vagus nerve. Operating modes of the pulse generator are stored. A maintenance dose of the electrical therapeutic stimulation is delivered to the vagus nerve via the pulse generator to restore cardiac autonomic balance through continuously-cycling, intermittent and periodic electrical pulses. A restorative dose of the electrical therapeutic stimulation is delivered to prevent initiation of or disrupt tachyarrhythmia through periodic electrical pulses delivered at higher intensity than the maintenance dose. The patient's normative physiology is monitored via a physiological sensor, and upon sensing a condition indicative of tachyarrhythmia, is switched to delivering the restorative dose to the vagus nerve.

A method for processing electrocardiograph (ECG) data using a garment includes determining, by a processor, a current working lead from ECG leads formed in advance using flexible electrodes in the garment based on a current ECG monitor type, and receiving, by the processor through lead wires corresponding to the current working lead, ECG data collected by flexible electrodes corresponding to the current working lead. A wearable apparatus for processing ECG data includes at least two flexible electrodes, in which the at least two flexible electrodes are capable of forming different leads based on predetermined configurations, at least two lead wires, and an ECG data collector configured to receive ECG data collected by the at least two flexible electrodes, in which each of the at least two flexible electrodes connects to the ECG data collector via at least one of the at least two lead wires.

A method of reconstruction of the standard 12-lead surface EKG given values of the electrical potential from an implanted medical device is described. This implanted device can be oriented in an arbitrary fashion and reconstruction technique is obtained through physical measurement of the orientation of the implanted device or correlation with a standard 12-lead EKG obtained from the patient.

A wearable cardioverter defibrillator (WCD) (10) and method (60) comprise a set of electrodes (12) for placement on a subject (14), a mechanism for electrically engaging (16) the set of electrodes to the subject's skin, and at least one non-invasive physiologic sensor (18, 20) configured for placement on the subject. A controller (24) monitors an output of the non-invasive physiologic sensor (18, 20) for detecting a change in a health parameter of the subject being indicative of one or more of a change in subject condition that may be a precursor to potential cardiac arrhythmia or a simultaneously occurring cardiac arrhythmia. Responsive to detecting the change, the controller (24) activates an alarm (26) for requesting a response from the subject (14) within a predetermined time. Responsive to receiving the subject's response within the predetermined time, the controller (24) inhibits the mechanism (16) from electrically engaging the set of electrodes (12) to the subject's skin. Responsive to not receiving the subject's response, the controller (24) initiates the mechanism (16) for electrically engaging the set of electrodes (12) to the subject's skin.

A system and method providing outpatient ECG monitoring and safe home based cardiac tele-rehabilitation. The system includes a recordation module for recording ECG signals using at least one lead, a tele-rehabilitation module for home based exercise management for a patient's recovery, the tele-rehabilitation module including a processing module for recognizing erroneous data from the ECG signals and an analysis module for calculating beat-to-beat annotations and determining if an ECG event and/or if a QT interval duration change has occurred. The system can include an exercise module for guiding the patient during an exercise session, a visual display that informs the patient to start and/or to stop the tele-rehabilitation exercise, a visual display and/or audible signal that informs the patient of an incoming or a missed tele-rehabilitation exercise session, and/or a communication module for transmitting/receiving data between the a cardiac tele-rehabilitation module and a physician/monitoring center.

Methods and devices providing multiple criteria for use in arrhythmia identification. Based on inputs including defined rules or parameters, one of a more conservative or more aggressive set of arrhythmia identification parameters can be selected. One or the other of the selectable sets of arrhythmia identification parameters may also be adaptive or modifiable during the use of the system, for example, in response to identified nonsustained episodes, the more conservative set of arrhythmia identification parameters can be modified to become still more conservative. Such modification of arrhythmia identification criteria allows reduced time to therapy when indicated, while allowing more deliberate decisions in other circumstances.

In some examples, processing circuitry of a medical device system determines, for each of a plurality of patient parameters, a difference metric for a current period based on a value of a patient parameter determined for the current period and a value of the patient parameter determined for an immediately preceding period, and determines a score for the current period based on a sum of the difference metrics for at least some of the plurality of patient parameters. The processing circuitry determines a threshold for the current period based on scores determined for N periods that precede the current period, compares the score for the current period to the threshold, and determines whether to generate an alert indicating that an acute cardiac event of the patient, e.g., ventricular tachyarrhythmia, is predicted, and/or deliver a therapy configured to prevent the acute cardiac event, based on the comparison.

A cardiac medical system, such as an implantable cardioverter defibrillator (ICD) system, receives a cardiac electrical signal by and senses cardiac events when the signal crosses an R-wave sensing threshold. The system determines at least one sensed event parameter from the cardiac electrical signal for consecutive cardiac events sensed by the sensing circuit and compares the sensed event parameters to P-wave oversensing criteria. The system detects P-wave oversensing in response to the sensed event parameters meeting the P-wave oversensing criteria; and adjusts at least one of an R-wave sensing control parameter or a therapy delivery control parameter in response to detecting the P-wave oversensing.

A method and system for determining a patient's risk of ventricular tachycardia are disclosed. The method includes receiving ECG signals from a patient and filtering the collected ECG signals to generate filtered ECG signals. The method further includes identifying a heart vector from the filtered ECG signals, and measuring a velocity of the heart vector movement. A change in curvature of the identified heart vector movement is quantified and a risk of ventricular tachycardia is determined based at least on the measured velocity and the quantified change in curvature of the identified heart vector movement.