A shield located within an implantable medical lead may be terminated in various ways. The shield may be terminated by butt, scarf, lap, or other joints between insulation layers surrounding the lead and an insulation extension. For lap joints, a portion of an outer insulation layer may be removed and a replacement outer insulation layer is positioned in place of the removed outer insulation layer, where the replacement layer extends beyond an inner insulation layer and the shield. The replacement layer may also lap onto a portion of the insulation extension. The barbs may be located between the replacement layer and the inner insulation layer or the insulation extension. The shield wires have ends at the termination point that may be folded over individually or may be capped with a ring located within one of the insulation layers of the jacket.

An apparatus comprises a magnetic field detection circuit, a cardiac signal sensing circuit, a memory circuit, a control circuit, and an arrhythmia detection circuit. The cardiac signal sensing circuit generates a cardiac signal representative of cardiac activity of a subject when coupled to sensing electrodes. The control circuit is operatively coupled to the magnetic field detection circuit; the cardiac signal sensing circuit, and the memory circuit. The control circuit stores cardiac signal data determined using the sensed cardiac signal, receives an indication of magnetic field detection by the magnetic field detection circuit, stores data obtained using the sensed cardiac signal during the magnetic field detection, and stores an identifier indicating the magnetic field detection in association with the data. The arrhythmia detection circuit processes the cardiac signal data to detect a cardiac arrhythmia event and confirm the cardiac arrhythmia event according to the magnetic field indication.

A cardiac pacing device to be disposed in a heart between an atrium and an atrial appendage protruding from the atrium includes a blocker and a regulator attached to the blocker. The blocker is configured to occlude the atrial appendage. The regulator is configured to contact the heart when the blocker is positioned between the atrium and the atrial appendage to occlude the atrial appendage in order to regulate a cardiac rhythm of the heart accordingly.

Embodiments describe herein generally pertain to implantable medical device (IMDs), and methods for use therewith, that can be used to automatically switch an IMD from its normal operational mode to an MRI safe mode, and vice versa, within increased specificity. In certain embodiments, a controller of the IMD uses a magnetic field sensor to determine whether a first magnetic field condition is detected, and uses an accelerometer to determine whether a positional condition is detected. In response to the first magnetic field condition being detected, and the positional condition being detected, the controller can use the magnetic field sensor to determine whether a second magnetic field condition is detected, which differs from the first magnetic field condition. The controller can then cause the IMD to enter the MRI safe mode based at least in part on the first and second magnetic field conditions and the positional condition being detected.

An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Techniques are described for magnetic field detection using a plurality of Hall sensors and chopper-amplifier circuit. Determination that a magnetic field is present from measurement from one of the Hall sensors may trigger confirmation or confirmation and reconfirmation of the presence of the magnetic field from measurements from one or more of the other Hall sensors.

A filtered feedthrough assembly includes a ferrule configured to be installed in an AIMD housing. An insulator is disposed within a ferrule opening. A conductive pathway is disposed within a passageway through the insulator. A filter capacitor is disposed on a device side having active and ground electrode plates disposed within a capacitor dielectric k greater than 0 and less than 1,000. A capacitor active metallization is electrically connected to the active electrode plates. A ground capacitor metallization is electrically connected to the ground electrode plates. The filter capacitor is the first filter capacitor electrically connected to the conductive pathway coming from a body fluid side into the device side. An active electrical connection electrically connects the conductive pathway to the capacitor active metallization. A ground electrical connection electrically connects the ground capacitor metallization to the ferrule. The filter capacitor is a flat-through or an X2Y attenuator filter capacitor.

A system for validating safety of a medical device in a presence of a magnetic resonance imaging (MRI) field is provided. The system includes a first electric field generating device configured to form first electric field and configured to receive a medical device at least partially within the first electric field, and a second electric field generating device configured to form a second electric field in proximity to the first electric field and configured to receive the medical device at least partially within the second electric field. One or more processors are configured to execute program instructions to calculate predicted parameter values of the medical device based on a transfer function, the transfer function defined to predict a safety characteristic of the medical device when in the presence of an MRI field, obtain measured parameter values from the medical device, the measured parameter values indicative of the safety characteristic of the medical device when exposed to the first and second electric fields, and compare the measured parameter values to the predicted parameter values in connection with validating the transfer function.

In some examples, an implantable medical device (IMD) includes a stimulation generator and/or sensing circuitry configured to generate electrical stimulation for delivery to or sensing the state of a patient via electrode coupled to the IMD; interconnect circuitry configured to transport the electrical stimulation from the stimulation generator to the lead, the interconnect circuitry comprising: a feedthrough capacitor; and one or more components and a switch that are collectively electrically connected in parallel with the feedthrough capacitor; and processing circuitry configured to selectively close the switch based on a magnetic resonance imaging (MRI) status of the IMD.

Systems and methods are disclosed for use with Implantable Medical Devices (IMD) such as Implantable Stimulator Devices. The system includes a permanent magnet which can be used to reset the IMD (such as during an emergency) and to place the IMD in a pairing mode to establish communications with an external device. An external device paired to the IMD can be used to place the IMD in an MRI mode that renders the IMD safe during a Magnetic Resonance Imaging (MRI) scan. In the event that the external device is unavailable to cause the IMD to exit the MRI mode, the bar magnet can also be used in the MRI mode to pair the IMD with another external device.