A medical device is configured to deliver anti-tachycardia pacing (ATP) in the presence of T-wave alternans. The device is configured to detect a ventricular tachyarrhythmia from a cardiac electrical signal received by the medical device. In response to the detected ventricular tachyarrhythmia, the device delivers a plurality of ATP pulses at alternating time intervals. The alternating time intervals comprise at least a first ATP time interval separating a first pair of the ATP pulses and a second ATP time interval different than the first ATP time interval. The second ATP time interval consecutively follows the first ATP time interval and separates a second pair of the ATP pulses.

A three-dimensional (3D) electrical mapping system and method may be used to generate a 3D image of the epicardial surface of a heart by integrating one or more epicardial images with a 3D image of the cardiac structure that may be generated by real-time 3D location and mapping system for cardiac mapping and ablation. The visual textural representation of the epicardial surface of the heart may be reconstructed using, for example, an image sensor or camera-based catheter to collect images of the epicardial surface. For each image that is captured, the system and method may store the image data along with the corresponding catheter location, orientation and/or distance information relative to the cardiac structure. The location, orientation, and/or distance information may be used to reconstruct a 3D textural model of the epicardial surface of the cardiac structure.

A cardiac lead system is provided. The lead is placed epicardially through the transverse pericardial sinus with integrated curvatures to prevent the lead from slipping out of the transverse pericardial sinus. Interaction with multiple chambers of the heart is facilitated in a single lead, without anchors that embed into the heart wall. Multiple electrodes can be grouped over each targeted heart area to ensure adequate electrical contact.

Systems and methods for electrocardiographic waveform analysis, data presentation and actionable alert generation are described. Electrocardiographic waveform data can be received from a wearable device associated with a patient. A mathematical analysis of at least a portion of the electrocardiographic waveform data can be performed to provide cardiac analytics. In instances where (1) a pathologically prolonged QT interval and (2) an R on T premature ventricular contraction and/or a ventricular tachycardia are detected from the cardiac analytics of the at least a portion of the electrocardiographic waveform data, an actionable alert can be generated and displayed with a visualization of the cardiac analytics.

An implantable medical device comprises a sensing module configured to obtain electrical signals from one or more electrodes and a control module configured to process the electrical signals from the sensing module in accordance with a tachyarrhythmia detection algorithm to monitor for a tachyarrhythmia. The control module detects initiation of a pacing train delivered by a second implantable medical device, determines a type of the detected pacing train, and modifies the tachyarrhythmia detection algorithm based on the type of the detected pacing train.

Apparatus and methods remove a voltage offset from an electrical signal, specifically a biomedical signal. A signal is received at a first operational amplifier and is amplified by a gain. An amplitude of the signal is monitored, by a first pair of diode stages coupled to an output of the first operational amplifier, for the voltage offset. The amplitude of the signal is then attenuated by the first pair of diode stages and a plurality of timing banks. The attenuating includes limiting charging, by the first pair of diode stages, of the plurality of timing banks and setting a time constant based on the charging. The attenuating removes the voltage offset persisting at a threshold for a duration of at least the time constant. Saturation of the signal is limited to a saturation recovery time while the saturated signal is gradually pulled into monitoring range over the saturation recovery time.

A system and method for controlling a monitoring mode or treatment mode of an implantable medical device based on the detection of an external signal. The system and related method allow for more frequent monitoring of medical parameters at times where more frequent monitoring is necessary, such as during or after a dialysis session, with less frequent monitoring at other times, allowing for a more efficient medical device. The invention also allows for the frequency or mode of treatment by the implantable medical device, or the transmission of data from the implantable medical device to be controlled based on the external signal.

A defibrillator for guiding a rescuer based on a probability of defibrillation success includes at least one output device and a processor and associated memory, the processor being configured to receive at least two ECG signals over time for a cardiac arrest victim, the at least two ECG signals including at least a first ECG signal at a first point in time and a second ECG signal at a second point in time, process the at least two ECG signals to determine at least two parameters related to the at least two ECG signals, the at least two parameters forming a sequence of parameter sets, analyze a trajectory of the sequence of parameter sets, determine the probability of defibrillation success based on the analysis of the trajectory, and control the at least one output device to provide one or more caregiver prompts based on the probability of defibrillation success.

An implantable monitoring device is disclosed for monitoring a patient's heart rate variability over time. The device includes a cardiac electrogram amplifier, a sensing electrode coupled to an input of the amplifier, timing circuitry, processing circuitry and a memory. The timing circuitry defines successive shorter time periods during each monitoring period. The processing circuitry relies upon electrogram activity that occurs during rest periods that extend as long as T1, all of which is stored into memory. Active periods are not considered as part of the heart rate variability calculation. The processing circuitry calculates median intervals between depolarizations of the patient's heart sensed by the amplifier during the shorter time periods and calculates a standard deviation of the median intervals during T2, a longer monitoring period.

A system and method for facilitating a cardiac rhythm disorder diagnosis with the aid of a digital computer is provided. A plurality of R-wave peaks are identified in a set of ECG data and a difference between recording times of successive pairs of the R-wave peaks are calculated as R-R intervals. A heart rate associated with each time difference is determined. An R-R interval plot of the ECG data is formed. The R-R intervals are plotted along an x-axis of the R-R interval plot and the heart rates associated with the R-R intervals are plotted along a y-axis of the R-R interval plot. A diagnostic composite plot is generated, including the R-R interval plot, a near field view of a portion of the ECG data, and an intermediate field view of a different portion of the ECG data for diagnosis of a cardiac event.