Abstract: An IMD may transition to an MRI mode automatically in response to detecting one or more conditions indicative of the presence of a strong magnetic field. Large static magnetic fields, such as those produced by an MRI device, may interact with the blood of a patient as it flows through the magnetic field to produce a voltage, a phenomenon referred to as the magnetohydrodynamic (MHD) effect. The voltage produced by the MHD effect is proportional to the strength of the magnetic field. As such, the voltage produced by blood flow in the strong magnetic field of an MRI device may result in a change in a characteristic of an electrogram (EGM). The IMD may detect the change in the characteristic of the EGM caused by the MHD effect and transition to operation in the MRI mode in response to at least the change in the EGM.

Abstract: An IMD may transition to an MRI mode automatically in response to detecting one or more conditions indicative of the presence of a strong magnetic field. Large static magnetic fields, such as those produced by an MRI device, may interact with the blood of a patient as it flows through the magnetic field to produce a voltage, a phenomenon referred to as the magnetohydrodynamic (MHD) effect. The voltage produced by the MHD effect is proportional to the strength of the magnetic field. As such, the voltage produced by blood flow in the strong magnetic field of an MRI device may result in a change in a characteristic of an electrogram (EGM). The IMD may detect the change in the characteristic of the EGM caused by the MHD effect and transition to operation in the MRI mode in response to at least the change in the EGM.

Abstract: A medical device lead is presented that includes an electrode assembly having a first electrode located near a distal end of the electrode assembly and a second electrode located near a proximal end of the electrode assembly. The electrode assembly also includes a conductive elongated coupler that is electrically coupled to the first electrode and capacitively coupled to the second electrode. At low frequencies and DC (e.g., during delivery of stimulation therapy), the capacitive coupling between the conductive elongated coupler and the second electrode presents a high impedance allowing little current to be redirected from the first electrode to the second electrode. However, at high frequencies (e.g., during an MRI scan) the capacitive coupling between the conductive elongated coupler and the second electrode presents a low impedance, resulting in a significant amount of induced current being redirected to the second electrode and dissipated into bodily fluid surrounding the second electrode.

Abstract: Techniques are described for controlling effects caused when an implantable medical device (IMD) is subject to a disruptive energy field. The IMD may include an implantable lead that includes one or more electrodes. The IMD may further include a first component having a parasitic inductance. The IMD may further include a second component having a reactance. In some examples, the reactance of the second component may be selected based on the parasitic inductance of the first component such that an amount of energy reflected along the lead in response to energy produced by an electromagnetic energy source is below a selected threshold. In additional examples, the parasitic inductance of the first component and the reactance of the second component are configured such that an amount of energy reflected along the lead in response to a frequency of electromagnetic energy is below a selected threshold.

Abstract: Techniques are described for controlling effects caused when an implantable medical device (IMD) is subject to a disruptive energy field. The IMD may include an implantable lead that includes one or more electrodes. The IMD may further include a first component having a parasitic inductance. The IMD may further include a second component having a reactance. In some examples, the reactance of the second component may be selected based on the parasitic inductance of the first component such that an amount of energy reflected along the lead in response to energy produced by an electromagnetic energy source is below a selected threshold. In additional examples, the parasitic inductance of the first component and the reactance of the second component are configured such that an amount of energy reflected along the lead in response to a frequency of electromagnetic energy is below a selected threshold.

Abstract: A semiconductor device has a die (10) overlying and electrically connected to a support structure (11), such as a substrate or a lead frame, via a plurality of interconnects. Aggressor interconnects (32, 38) are noise sources to victim interconnects (29, 59) carrying sensitive signals. An arrangement of shield interconnects (51-58) surround the victim interconnect (29, 59) in a cage-like structure to significantly block noise from the aggressor interconnect. In one form the shield interconnects are ground or power supply and the victim interconnect may be, for example, a clock signal or an RF signal. The number of shield interconnects and the number of protected victim interconnects varies depending upon design requirements. Either wire bonding or other interconnect technology (e.g. bump) is applicable.