Abstract: An implantation and/or retrieval device for a leadless cardiac pacing device may include a first elongate shaft including a lumen; a second elongate shaft slidably disposed within the lumen of the first elongate shaft; an end cap assembly fixedly attached to a distal end of the first elongate shaft; and a plurality of wires attached to the second elongate shaft and extending distally from the end cap assembly, the plurality of wires being movable relative to the end cap assembly. The plurality of wires is configured to engage a proximal hub of the leadless cardiac pacing device. The plurality of wires forms a plurality of wire loops extending distally from the end cap assembly.

Abstract: A neurostimulation system provides for capture verification and stimulation intensity adjustment to ensure effectiveness of vagus nerve stimulation in modulating one or more target functions in a patient. In various embodiments, stimulation is applied to the vagus nerve, and evoked responses are detected to verify that the stimulation captures the vagus nerve and to adjust one or more stimulation parameters that control the stimulation intensity.

Abstract: This document discusses, among other things, systems and methods to determine amplitude and morphology variations of a first heart sound over a first number of cardiac cycles, and to calculate an atrial fibrillation metric indicative of an atrial fibrillation episode of the heart using the determined amplitude and morphology variations. The systems and methods can determine a variability score using the determined amplitude and morphology variations, and can calculate the atrial fibrillation metric using the variability score.

Abstract: An implantable medical device for implantation into a patient may include a housing, a pulse generation circuit disposed at least partially within the housing, a plurality of electrodes electrically coupled to the pulse generation circuit, the plurality of electrodes being exposed external to the housing, and a controller operatively coupled to the pulse generation circuit. The controller may be configured to command the pulse generation circuit to deliver a phasic conducted communication pulse via at least two of the plurality of electrodes. Additionally, the phasic conducted communication pulse may comprise a first phase having a first polarity followed by a second phase having an opposite second polarity, wherein the second phase may have a duration of less than 60 microseconds, and wherein the first phase having may have a duration of between five percent and eighty percent of the duration of the second phase.

Abstract: A method of preventing infection resulting from implanting a medical device. The method includes installing a polymer device at least substantially within a subcutaneous pocket formed to contain a housing of the medical device, and installing the medical device housing in the subcutaneous pocket. The polymer device includes a bioresorbable polymer structure and an antimicrobial agent configured to elute from the polymer structure. The polymer device covers less than about 20% of the surface area of the medical device housing.

Abstract: A medical device capacitor assembly can include a capacitor including a plurality of anodes and cathodes, wherein the capacitor has a first major face, a second major face opposite the first major face, and a third face extending between the first major face and the second major face. A first insulating film can be sized and shaped to assemble against the first major face, and can include a first set of flaps sized and shaped to cover at least a portion of the third face. A second insulating film sized and shaped to assemble against the second major face, and can include a second set of flaps sized and shaped to cover at least a portion of the third face.

Abstract: Systems and methods for pacing cardiac conductive tissue are described. A medical system includes an electrostimulation circuit to generate His-bundle pacing (HBP) pulses for delivery at or near a His bundle of the heart. A control circuit may time the delivery of the HBP pulses within a tissue refractory period subsequent to an intrinsic His-bundle activation of a first His-bundle portion. Based on an evoked His-bundle activation of a second His-bundle portion, the system may determine whether correction of intra-Hisian block has occurred. The system additionally includes a threshold test circuit to determine an individualized pacing threshold representing minimal energy to excite the His bundle and to correct the cardiac conduction abnormality.

Abstract: An implantable medical device (IMD) with a receiving coil for wireless power transfer. The receiving coil may be disposed about a flux concentrator located in a housing of the IMD. The flux concentrator may concentrate non-radiative near-field energy through the receiving coil. In some cases, the near-field energy may be captured and converted into electrical energy that may be used to recharge a rechargeable power source of the IMD.

Abstract: An Implantable Medical Device (IMD) configured to be implantable in a ventricle of a patient's heart may include a housing, a first electrode secured relative to the housing, a second electrode secured relative to the housing, the second electrode spaced from the first electrode, and circuitry in the housing operatively coupled to the first electrode and the second electrode. The circuitry may be configured to identify a measure of impedance between the first electrode and the second electrode at each of a plurality of times during a cardiac cycle. Each measure of impedance may represent a measure of volume of the ventricle in which the IMD is implanted. In some cases, the circuitry may generate a pacing pulse, the timing of which is based at least in part on the measure of volume of the ventricle at two or more of the plurality of times during the cardiac cycle.

Abstract: Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

Abstract: Implantable medical devices (IMD), such as but not limited to leadless cardiac pacemakers (LCP), subcutaneous implantable cardioverter defibrillators (SICD), transvenous implantable cardioverter defibrillators, neuro-stimulators (NS), implantable monitors (IM), may be configured to communicate with each other. In some cases, a first IMD may transmit instructions to a second IMD. In order to improve the chances of a successfully received transmission, the first IMD may transmit the instructions several times during a particular time frame, such as during a single heartbeat. If the second IMD receives the message more than once, the second IMD recognizes that the messages were redundant and acts accordingly.

Abstract: Systems and methods for communicating between medical devices. In one example, an implantable medical device comprising may comprise one or more electrodes and a controller coupled to the electrodes. The controller may be configured to receive a first communication pulse at a first communication pulse time and a second communication pulse at a second communication pulse time via the one or more electrodes. The controller may further be configured to identify one of three or more symbols based at least in part on the time difference between the first communication pulse time and the second communication pulse time.

Abstract: In one example, a method of monitoring a sustained activity of a human or animal subject for the purpose of determining a risk group includes detecting a physical activity signal from the subject, determining a magnitude of the detected physical activity signal, initiating a timer in response to determining the magnitude of the physical activity signal exceeding an activity level threshold, triggering storing at least one value associated with the physical activity signal only when the magnitude of the physical activity signal exceeds the activity level threshold and the timer is greater than a duration threshold, and determining, using the processor circuit, an indication of the subject's cardiovascular disease based on the stored value.

Abstract: A delivery device for delivering an implantable leadless pacing device may include a catheter shaft a distal holding section for receiving the implantable leadless pacing device. In some cases, the delivery device may include a flow-sensing device to determine a pressure or flow-rate of a fluid within the distal holding section. Also included may be a handle assembly and a deployment mechanism to deploy the implantable leadless pacing device.

Abstract: An implantable medical device (IMD) may be configured for deployment at a patient's atrioventricular septum in order to sense and/or pace a patient's heart. The atrioventricular septum of the patient's heart may have an atrial facing side defining part of the right atrium of the patient's heart and a ventricle facing side defining part of the left ventricle of the patient's heart. The IMD may include a first component configured to be positioned at least in part in the right atrium of the patient's heart proximate the atrioventricular septum, and a second component configured to be positioned at least in part in the left ventricle.

Abstract: An IMD may include a housing with a controller and a power supply disposed within the housing. A distal electrode may be supported by a distal electrode support that biases the distal electrode toward an extended position in which the distal electrode extends distally from the distal end of the housing and allows the distal electrode to move proximally relative to the extended position in response to an axial force applied to the distal electrode in the proximal direction. In some cases, the distal electrode support may include a tissue ingrowth inhibiting outer sleeve that extends along the length of the distal electrode support and is configured to shorten when the distal electrode moves proximally relative to the extended position and to lengthen when the distal electrode moves back distally toward the extended position in order to accommodate movement of the distal electrode.

Abstract: Implantable medical devices such as leadless stimulation devices that may provide longer battery life while minimizing device size. In some cases, having the outer housing of the implantable medical device serve multiple roles, such as the battery case for an internal battery, may permit reduced device size by eliminating one or more layers or components within the device.

Abstract: Methods and devices for classifying a cardiac response to pacing involve establishing a retriggerable cardiac response classification window. A first cardiac response classification window is established subsequent to delivery of a pacing pulse. A cardiac signal following the pacing stimulation is sensed in the first classification window. A second cardiac response classification may be triggered if a trigger characteristic is detected in the first classification window. The cardiac signal is sensed in the second classification window if the second classification window is established. The cardiac response to the pacing stimulation is determined based on characteristics of the cardiac signal. The cardiac response may be determined to be one of a captured response, a non-captured response, a non-captured response added to an intrinsic beat, and a fusion/pseudofusion beat, for example.

Abstract: Delivery devices, systems, and methods for delivering implantable leadless pacing devices are disclosed. An example delivery device may an outer tubular member and an inner tubular member slidably disposed within the lumen of the outer tubular member. A distal holding section may extend distally of a distal end of the inner tubular member and define a cavity therein for receiving an implantable leadless pacing device. The device may further include a hub portion including at least a first hub portion affixed adjacent to the proximal end of the outer tubular member and a second hub portion affixed adjacent to the proximal end of the inner tubular member. A first locking mechanism configured to releasably couple the outer tubular member and the inner tubular member may be disposed within the hub portion.

Abstract: A leadless pacing device may include a housing having a proximal end and a distal end, and a set of one or more electrodes supported by the housing. The housing may include a first a distal extension extending distally from the distal end thereof. One or more electrodes may be supported by the distal extension. The leadless pacing device may be releasably coupled to an expandable anchor mechanism.