Abstract: Regulating cardiac activity may include pacing the patient's heart at a starting pacing rate and instigating an intrinsic heart beat search algorithm that includes pacing at a reduced rate for a period of time and capturing electrical signals representative of cardiac electrical activity while pacing at the reduced rate in order to determine a presence or absence of intrinsic heart beats. If intrinsic heart beats are not detected, the heart may be paced at a further reduced rate for a period of time. If intrinsic beats are detected, the heart may be paced again at the starting pacing rate. This may continue until intrinsic heart beats are detected or until a lower search rate limit is reached. Diagnostic data may be collected at each stage and transmitted to a display device for analysis by a physician or the like.

Abstract: Systems and methods for classifying a cardiac arrhythmia are discussed. An exemplary system includes a correlator circuit to generate autocorrelation sequences using information of cardiac activity of a subject, including signal segments taken from a cardiac signal at respective elapsed time with respect to reference time. The correlator circuit can generate a correlation image using the autocorrelation sequences. The correlation image may be constructed by stacking the autocorrelation sequences according to the elapsed time of signal segments. An arrhythmia classifier circuit can classify the cardiac activity of the subject as one of arrhythmia types using the correlation image.

Abstract: A system for lead integrity monitoring includes an implantable medical device (IMD) having a housing enclosing a control circuit; and a lead, having a first sensor. The lead is coupled to the housing and electrically coupled to the control circuit. The system also includes at least one processing device configured to identify a first lead failure alert based on a first set of information; obtain a second set of information generated by a second sensor; perform an evaluation of the first set of information in the context of the second set of information; and confirm or cancel the first lead failure alert based on the evaluation.

Abstract: This document discusses, among other things, systems and methods to receive cardiac electrical information and premature ventricular contraction (PVC) information of a subject, detect atrial fibrillation (AF) of the subject using the received cardiac electrical information, and adjust AF detection using the received PVC information.

Abstract: This document discusses, among other things, systems and methods to detect an initial arrhythmia event indication and, after a threshold amount of detection window intervals detecting the initial arrhythmia event indication, adjust a set of arrhythmia parameters or at least one of a respective set of parameter thresholds to increase sensitivity of an extended arrhythmia event indication detection.

Abstract: An example of a system may include a sensing circuit and an atrial fibrillation (AF) detection circuit. The sensing circuit may be configured to sense a cardiac signal indicative of atrial and ventricular depolarizations. The AF detection circuit may be configured to detect AF using the cardiac signal and may include a detector and a detection enhancer. The detector may be configured to detect the ventricular depolarizations using the cardiac signal, to measure ventricular intervals each between two successively detected ventricular depolarizations, and to detect the AF using the ventricular intervals. The detection enhancer may include a respiratory sinus arrhythmia (RSA) detector configured to detect RSA using the cardiac signal and may be configured to verify each detection of the AF based on whether the RSA is detected.

Abstract: An apparatus includes a sensing circuit configured to generate a sensed physiological signal that includes physiological information of a subject, a detection circuit, and a control circuit. The detection circuit detects a physiological condition of a subject using the physiological signal. The control circuit stores sampled values of a segment of the physiological signal in temporary memory storage; and stores the sampled values in non-temporary storage in response to receiving an indication of continued detection of the physiological condition.

Abstract: This document discusses, among other things, apparatus, systems, and methods to determine a first atrial fibrillation (AF) indication using received information about a heart over a first period, to cluster depolarization information about the heart over the first period, and to discriminate between an atrial fibrillation (AF) event and a non-AF event in the first period using the determined first AF indication the clustered depolarization information.

Abstract: Systems and methods for pacing cardiac conductive tissue are described. An exemplary system includes an electrostimulation circuit that may generate HBP pulses to stimulate patient physiologic conduction pathway, such as a His bundle or a bundle branch. The system includes an arrhythmia detector to detect an atrial tachyarrhythmia (AT) with intermittent ventricular conduction. A control circuit may sense ventricular activation and, in response to the detected AT indication, determine or update a His-bundle pacing (HBP) configuration. The HBP may be recursively updated on a beat-by-beat basis using the sensed ventricular activation. The electrostimulation circuit may deliver HBP according to the determined or adjusted HBP configuration to regularize ventricular rate during AT.

Abstract: Systems and methods for detecting cardiac arrhythmia are discussed. An exemplary arrhythmia detection system can receive physiologic information of the patient, measure a first signal metric using a first portion of the received physiologic information, and determine an arrhythmia detection duration using a comparison between the measured first signal metric and a reference signal metric value. The system includes an arrhythmia detector to detect an AT episode using a second portion of the physiologic information corresponding to the determined arrhythmia detection duration.

Abstract: Systems and methods for detecting cardiac arrhythmias such as atrial tachyarrhythmia (AT) are discussed. An exemplary system includes a ventricular beat analyzer circuit to detect ventricular beats and assess ventricular activity, such as to evaluate a ventricular rate stability. The system includes an arrhythmia detector circuit to detect respective AT indications in distinct time periods using portions of received physiologic information during the distinct time periods. A control circuit can monitor the ventricular beats on a beat-by-beat basis, in response to the detected ventricular beats satisfying an instability condition, trigger AT detections during the distinct time periods and withhold AT detection in a subsequent time period if no AT is detected in the present time period. An AT characteristic may be generated using the detected AT indications. A therapy may be delivered in accordance with the AT characteristic.

Abstract: Systems and methods for dynamically controlling HBP delivery based on patient AV conduction status are disclosed. An exemplary medical system includes an electrostimulation circuit to generate HBP pulses to stimulate a His bundle or a bundle branch of the heart. An AV conduction monitor circuit continuously or periodically assesses AV conduction status, and detects an indication of presence or absence of AV conduction abnormality. If an AV conduction abnormality is indicated, a control circuit may control the electrostimulation circuit to deliver the HBP pulses. Ventricular backup pacing may be delivered if HBP fails to capture and elicit ventricular activation. When the AV conduction become normal, the control circuit may withhold HBP delivery and promote patient intrinsic ventricular activation.

Abstract: Systems and methods for pacing cardiac conductive tissue are described. In an embodiment, a medical system includes an electrostimulation circuit to generate pacing pulses to stimulate a His bundle or a bunch branch. A sensing circuit senses a far-field ventricular activation, determines a cardiac synchrony indicator using the far-field ventricular activation in response to His bundle or bundle branch pacing, and verifies His-bundle capture status using the determined cardiac synchrony indicator. The system can determine a pacing threshold using the capture status under different stimulation strength values. The electrostimulation circuit can deliver stimulation pulses in accordance with the determined pacing threshold.

Abstract: A system for monitoring a subject for an arrhythmia includes an external monitoring device (EMD) configured to be disposed outside of a subject's body. The EMD includes a first communication component configured to receive, from a medical device, a first physiological parameter signal and an indication of a detected trigger event associated with a first portion of the first physiological parameter signal. The trigger event is indicative of a potential arrhythmia. The EMD also includes an analysis component configured to (1) identify a second portion of the first physiological parameter signal, where the second portion satisfies a discard criterion, (2) discard the second portion, and (3) perform an arrhythmia confirmation evaluation using a third portion of the first physiological parameter signal.

Abstract: An apparatus includes a sensing circuit configured to generate a sensed physiological signal representative of cardiac activity of a subject, an arrhythmia detection circuit, a control circuit, and a memory. The arrhythmia detection circuit detects an episode of atrial fibrillation (AF) in the sensed cardiac signal using a first AF detection criterion, and detects the episode of AF using a second AF detection criterion. The first AF detection criterion has greater sensitivity to AF detection than the second AF detection criterion, and the second AF detection criterion has greater specificity to AF detection than the first AF detection criterion. The control circuit initiates storing of sampled values of a segment of the cardiac signal that includes the episode of AF when the episode of AF is detected by both the first AF detection criterion and the second AF detection criterion.

Abstract: Systems, devices, and methods for monitoring and assessing immunotherapy toxicity are discussed. An exemplary system receives physiologic information from a patient using an ambulatory medical device. In response to an immunotherapy such as CAR T-cell therapy, the system determines a toxicity indication using the received physiologic information. A therapy can be initiated or adjusted using the toxicity indication.

Abstract: Systems and methods for presenting physiologic data to a user are discussed. An exemplary system includes a presentation control circuit configured to generate signal metrics from data subsets of a physiologic signal corresponding to a device-detected presence of a physiologic event. The signal metrics represent characteristics of the physiologic event. The presentation control circuit may determine, from the plurality of data subsets, a target subset of clinical significance, which has the corresponding signal metric satisfying a specific condition. The presentation control circuit may present the recognized target subset over other subsets of the physiologic data. A user may adjudicate the device detection of the physiologic event or adjust device parameters.

Abstract: An apparatus includes a sensing circuit configured to generate a sensed physiological signal representative of cardiac activity of a subject, and an arrhythmia detection circuit. The arrhythmia detection circuit is configured to monitor information corresponding to ventricular depolarization (V-V) intervals using the sensed physiological signal; determine a V-V interval distribution; determine a heart rate density index (HRDI) as a portion of samples of the V-V interval distribution corresponding to a V-V interval occurring most often in the distribution; and generate an indication of atrial fibrillation (AF) using the HRDI.

Abstract: Systems and methods for detecting physiologic events in a patient are described herein. An embodiment of a medical system includes a memory circuit to store physiologic event episodes detected and recorded by a medical device. The system includes a control circuit to analyze the stored physiologic event episodes, and determine a presence of a target cardiac event under a plurality of detection settings. Using the determined presence of the target cardiac event from the stored physiologic event episodes, and user adjudication of the stored event episodes, the control circuit may select, from the plurality of detection settings, a detection setting to detect a subsequent target cardiac event. The control circuit may also prioritize the physiologic event episodes for storage in the memory circuit.

Abstract: Systems and methods for pacing cardiac conductive tissue are described. An embodiment of a medical system includes an electrostimulation circuit to generate His-bundle pacing (HBP) pulses to stimulate a His bundle, and a cardiac event detector to detect a His-bundle activity within a time window following an atrial activity. The cardiac event detector may use a cross-chamber blanking, or an adjustable His-bundle sensing threshold, to avoid or reduce over-sensing of far-field atrial activity and inappropriate inhibition of HBP therapy. The electrostimulation circuit may deliver HBP in the presence of the His-bundle activity. The system may further recognize the detected His-bundle activity as either a FFPW or a valid inhibitory event, and deliver or withhold HBP therapy based on the recognition of the His-bundle activity.