Cardiac electrical activity is monitored from tissue of the patient using the plurality of external electrodes. One or more cardiac metrics of the patient are generated based on the monitored electrical activity. It is determined whether the patient is a candidate for a cardiac resynchronization therapy (CRT) device based on a first global dyssynchrony metric using the one or more cardiac metrics if the patient has a right bundle branch block. It is determined whether the patient is a candidate for a cardiac resynchronization therapy (CRT) device based on a second global dyssynchrony metric using the one or more cardiac metrics if the patient does not have a right bundle branch block.

Systems and methods are described herein for determining whether or not each of a plurality of cardiac signals monitored from a plurality of electrodes is stable. A dispersion signal may be generated based on the plurality of cardiac signals, and low dispersion time period may be selected within which the cardiac signals may be analyzed for stability.

This disclosure is directed to devices, systems, and techniques for dynamically adjusting a bio impedance measurement range. An example device includes a plurality of electrodes. The device also includes sensing circuitry configured to sense a bio impedance and processing circuitry. The processing circuitry is configured to apply an excitation signal to the sensing circuitry and, based on the application of the excitation signal, determine a sensed bio impedance value within a bio impedance measurement range. The processing circuitry is also configured to determine whether the sensed bio impedance value is within a predetermined portion of the bio impedance measurement range for a predetermined period of time and based on the sensed bio impedance value being within the predetermined portion of the bio impedance measurement range for the predetermined period of time, adjust the excitation signal.

In one example, this disclosure is directed to a kit for intravascular implantation of an implantable medical device within a patient, the kit comprising an elongated outer sheath forming an inner lumen with a distal opening, the outer sheath sized to traverse a vasculature of the patient, and an elongated inner sheath with an enlarged distal portion, wherein the enlarged distal portion is configured to substantially fill the inner lumen and close-off the distal opening of the outer sheath. The enlarged distal portion is slidable relative to the outer sheath. The inner sheath further includes a tether with a helical element that is remotely controllable from a proximal end of the inner sheath to release the implantable medical device from a distal portion of the outer sheath.

An example method includes establishing a communications link between an electrophysiology (EP) monitoring system and an implantable medical device (IMD). IMD electrical data is received at the monitoring system via the communications link. The IMD electrical data may be synchronized with EP measurement data to provide synchronized electrical data based on timing of a synchronization signal sensed by an IMD electrode and/or EP electrodes. The method also includes computing reconstructed electrical signals for locations on a surface of interest within the patient's body based on the synchronized electrical data and geometry data. The geometry data represents locations of the EP electrodes, a location of the IMD electrode within the patient's body and the surface of interest.

VfA cardiac therapy uses an implantable medical device or system. The implantable medical device includes a tissue-piercing electrode implanted in the basal and/or septal region of the left ventricular myocardium of the patient's heart from the triangle of Koch region of the right atrium through the right atrial endocardium and central fibrous body. The device may include a right atrial electrode, a right atrial motion detector, or both. The device may be implanted completely within the patient's heart or may use one or more leads to implant electrodes in the patient's heart. The device may be used to provide cardiac therapy, including single or multiple chamber pacing, atrioventricular synchronous pacing, asynchronous pacing, triggered pacing, cardiac resynchronization pacing, or tachycardia-related therapy. A separate medical device may be used to provide some functionality for cardiac therapy, such as sensing, pacing, or shock therapy.

A device and method for manufacturing an implantable cardiac monitor device are provided. The method joins a feed-through assembly to a device housing having electronic components therein. The feed-through assembly includes conductors having distal ends connected to the electronic components and has proximal ends projecting from the feed-through assembly. The method assembles a header having a sensing electrode and an antenna embedded within a non-conductive header body. The electrode and antenna includes corresponding interconnection plates. The header body includes a housing mounting surface that includes at least one passage aligned with an interconnect cavity that includes the interconnection plates. The header body further includes a window exposing the interconnect cavity and interconnect regions. The method further directs the proximal ends of the conductors through the passage to align with the interconnect regions and secures the proximal ends and the interconnect regions to one another through the window.

Implanted medical device data is received, where the data was sensed by a first lead portion and a sensor over a time period. The number of detected noise events sensed by the first lead portion is counted based on applying first noise detection criteria to the data sensed by the first lead portion. The number of detected noise events over the sensor is counted based on applying second noise detection criteria to the data sensed by the sensor. The mean number of detected noise events is calculated for the first lead portion and sensor based on the number of noise events sensed by the first lead portion and the number of noise events sensed by the sensor. Potential lead failure in the first lead is recorded if the number of detected noise events over the first lead is greater than the mean number of noise events by at least 5%.

Subcutaneous implantation tools and methods of implanting a subcutaneous device using the same. The tool may include a tool body having a longitudinally extending recess having a distal opening and having a tunneler at a distal end of the tool body extending from the distal opening of the recess. The tool may include a plunger slidably fitting within at least a portion of the tool body recess. The recess may be configured to receive an implantable device and the tunneler preferably extends distally from the recess at a position laterally displaced from the device when the device is so located in the recess. Movement of the plunger distally within the recess advances the device distally out of the recess and alongside of and exterior to the tunneler.

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.