Abstract: An implantable medical system may include an implantable medical lead including at least one electrode and an implantable medical device. The implantable medical device comprises an electromagnetic interference (EMI) detection module that monitors for one or more particular characteristics of EMI. A control module is configured to control a therapy module to generate single stimulation pulses while operating the IMD in a first operating mode. In response to detecting the condition indicative of the presence of EMI, the control module switches the IMD from the first operating mode to a second operating mode and generates at least one group of two or more stimulation pulses in close proximity to one another in place of a single stimulation pulse while operating the IMD in the second operating mode.

Abstract: An implantable medical system includes an implantable medical lead including at least one electrode and an implantable medical device (IMD) coupled to the implantable medical lead. The IMD includes a sensing module that obtains electrical signals on the implantable medical lead. The electrical signals on the implantable medical lead include cardiac signals as well as noise-induced signals. The IMD also includes a noise detection module that obtains noise signals independently of the electrical signals on the implantable medical lead. A control module of the IMD adjusts a sensing threshold of the sensing module in response to detecting the noise signals via the noise detection module. In instances in which the amplitude of the noise-induced signal on the lead is too large, the IMD may transition to a noise operating mode specifically designed to accommodate noisy environments.

Abstract: This disclosure provides a pacing technique that reduces the effect of oversensing caused by noise on pacing therapy. The IMD delivers a pacing pulse subsequent to sensing an electrical signal on the lead when the sensed electrical signal coincides with an independently detected noise signal and the sensed electrical signal occurs during a period of time of an expected intrinsic cardiac signal. The IMD may, in some instances, trigger delivery of the pacing pulse during the escape interval instead of waiting for the escape interval to expire. Pacing in accordance with the techniques of this disclosure may allow for improved therapy during an MRI procedure by decreasing the risk associated with inappropriate pacing inhibition as well as decreasing the risk associated with pacing during the vulnerable period of the cardiac cycle.

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: An IMD is selectively configurable to support a plurality of programming options for enabling and disabling an exposure operating mode of the device. In one example, the IMD may support at least two of a manual exposure mode programming option in which the exposure operating mode is manually enabled and manually disabled, an automatic exposure mode programming option in which the exposure operating mode is automatically enabled and automatically disabled, or a semi-automatic exposure mode programming option in which the exposure operating mode is either automatically enabled and manually disabled or manually enabled and automatically disabled. In this manner, the IMD may support more than one way for enabling and disabling the exposure operating mode to provide flexibility in the clinical workflows associated with programming the IMD into an exposure operating mode for a medical procedure, such as an MRI scan.

Abstract: An implantable medical device (IMD) may be configured into a sensing only mode in which the IMD does not delivery therapy. For example, the IMD may be configured to operate in a sensing only mode to reduce the undesirable effects that may be caused by external fields, such as those generated by an MRI device. However, there may be instances, such as a change in the patient's condition, in which it may be desirable to transition from the sensing only mode to a pacing mode to provide therapy. In accordance with the techniques described herein, the IMD monitors signals on one or more leads coupled to the medical device while operating in the sensing only mode and transitions to a pacing mode in response to not detecting a minimum number of signals on the one or more leads.

Abstract: An implantable medical device (IMD) receives an input associated with the presence of an environment having an external source that generates an interfering signal, such as an MRI device. The IMD adjusts a first set of one or more sensing parameters of a sensing module of the IMD in response to receiving the input associated with the presence of the environment. In this manner, the IMD operates in accordance with the adjusted sensing configuration in the presence of the interfering signal in an attempt to obtain a more detailed representation of the signal including noise caused by the interfering signal. The IMD analyzes the signals sensed using the first set of adjusted sensing parameters to determine if further adjustment is desired. If desired, the IMD adjusts a second set of one or more sensing parameters of the sensing module based on the analysis.

Abstract: An implantable medical device (IMD) adjusts a sensing configuration of a sensing module prior to or immediately subsequent to entering an environment having an external source that generates the interfering signal. The IMD may, for example, adjust a sampling frequency, resolution, input range, gain, bandwidth, filtering parameters, or a combination of these or other sensing parameters of the sensing module. These adjustments enable the sensing module to obtain a more detailed representation of the sensed signals, including the noise components of the sensed signals caused by the interfering signal. Without having an adequate representation of the noise components of the sensed signal, it is difficult to separate the noise components of the sensed signal from the cardiac electrical signal.

Abstract: A device to which an implantable lead is coupled may be configured to perform one or more impedance measurements subsequent to a sensed physiological event to determine whether the sensed physiological event is possibly associated with noise induced by an interfering signal. Interfering signals, such as electromagnetic fields generated by an external source, may induce voltages or currents on conductors of the implantable lead, which will have an effect on lead impedance measurements. By measuring one or more impedances associated with the lead during a time window that substantially coincides with the sensed physiological event, the device may determine whether the sensed events may have resulted from interference. The device may determine whether to further adjust operation of the IMD based on the classification of the sensed physiological event and a classification of one or more previously sensed physiological events.

Abstract: An IMD is selectively configurable to support a plurality of programming options for enabling and disabling an exposure operating mode of the device. In one example, the IMD may support at least two of a manual exposure mode programming option in which the exposure operating mode is manually enabled and manually disabled, an automatic exposure mode programming option in which the exposure operating mode is automatically enabled and automatically disabled, or a semi-automatic exposure mode programming option in which the exposure operating mode is either automatically enabled and manually disabled or manually enabled and automatically disabled. In this manner, the IMD may support more than one way for enabling and disabling the exposure operating mode to provide flexibility in the clinical workflows associated with programming the IMD into an exposure operating mode for a medical procedure, such as an MRI scan.

Abstract: This disclosure describes techniques for configuring an IMD into the exposure operating mode. Prior to a medical procedure that generates a disruptive energy field, such as an MRI scan, an electronic prescription is configured to indicate that the IMD is authorized for the medical procedure that includes a disruptive energy field. The electronic prescription includes one or more designated bits within a storage element of the IMD. When the patient in which the IMD is implanted arrives for the medical procedure, a user (such as an MRI operator) interacts with a telemetry device to determine whether the electronic prescription is configured. Upon determining that the electronic prescription is configured, the IMD transitions into the exposure operating mode designed for operation in the disruptive energy field. In this manner, the electronic prescription confirms to the user that that the IMD has been checked for suitability for operation during the medical procedure.

Abstract: This disclosure describes techniques for configuring an IMD into the exposure operating mode. Prior to a medical procedure that generates a disruptive energy field, such as an MRI scan, an electronic prescription is configured to indicate that the IMD is authorized for the medical procedure that includes a disruptive energy field. The electronic prescription includes one or more designated bits within a storage element of the IMD. When the patient in which the IMD is implanted arrives for the medical procedure, a user (such as an MRI operator) interacts with a telemetry device to determine whether the electronic prescription is configured. Upon determining that the electronic prescription is configured, the IMD transitions into the exposure operating mode designed for operation in the disruptive energy field. In this manner, the electronic prescription confirms to the user that that the IMD has been checked for suitability for operation during the medical procedure.

Abstract: An implantable medical device (IMD) determines an effect of the disruptive energy field and adjusts one or more operating parameters of the IMD based on at least the determined effect. In some instances, the IMD may determine an actual effect of the disruptive energy field, such as a temperature change, impedance change, pacing or sensing threshold change, MRI-induced interference one pacing or sensing, or other actual effect. In other instances, the IMD may determine a predicted effect of the disruptive energy field based on one or more characteristics of the exposure. In any case, the IMD adjusts one or more parameters based on at least the determined effect.

Abstract: An implantable medical device (IMD) configures one or more operating parameters of the IMD based on a type of source of a disruptive energy field to which the IMD is exposed. The disruptive energy field may, in one example, include magnetic and/or radio frequency (RF) fields generated by an MRI scanner. In one aspect, the IMD may distinguish between different types of MRI scanners and select an exposure operating mode tailored to reduce the effects of the particular type of MRI scanner. In another aspect, the IMD may adjust one or more operating parameters that will be used when the IMD returns to a normal operating mode after exposure to the MRI scanner based on the type of MRI scanner to which the IMD is exposed.

Abstract: An implantable medical device (IMD) configures one or more operating parameters of the IMD based on a type of source of a disruptive energy field to which the IMD is exposed. The disruptive energy field may, in one example, include magnetic and/or radio frequency (RF) fields generated by an MRI scanner. In one aspect, the IMD may distinguish between different types of MRI scanners and select an exposure operating mode tailored to reduce the effects of the particular type of MRI scanner. In another aspect, the IMD may adjust one or more operating parameters that will be used when the IMD returns to a normal operating mode after exposure to the MRI scanner based on the type of MRI scanner to which the IMD is exposed.

Abstract: An IMD is selectively configurable to support a plurality of programming options for enabling and disabling an exposure operating mode of the device. In one example, the IMD may support at least two of a manual exposure mode programming option in which the exposure operating mode is manually enabled and manually disabled, an automatic exposure mode programming option in which the exposure operating mode is automatically enabled and automatically disabled, or a semi-automatic exposure mode programming option in which the exposure operating mode is either automatically enabled and manually disabled or manually enabled and automatically disabled. In this manner, the IMD may support more than one way for enabling and disabling the exposure operating mode to provide flexibility in the clinical workflows associated with programming the IMD into an exposure operating mode for a medical procedure, such as an MRI scan.

Abstract: An IMD is selectively configurable to support a plurality of programming options for enabling and disabling an exposure operating mode of the device. In one example, the IMD may support at least two of a manual exposure mode programming option in which the exposure operating mode is manually enabled and manually disabled, an automatic exposure mode programming option in which the exposure operating mode is automatically enabled and automatically disabled, or a semi-automatic exposure mode programming option in which the exposure operating mode is either automatically enabled and manually disabled or manually enabled and automatically disabled. In this manner, the IMD may support more than one way for enabling and disabling the exposure operating mode to provide flexibility in the clinical workflows associated with programming the IMD into an exposure operating mode for a medical procedure, such as an MRI scan.

Abstract: An implantable medical device (IMD) automatically determines at least a portion of the parameters and, in some instances all of the parameters, of an exposure operating mode based on stored information regarding sensed physiological events or therapy provided over a predetermined period of time. The IMD may configure itself to operate in accordance with the automatically determined parameters of the exposure operating mode in response to detecting a disruptive energy field. Alternatively, the IMD may provide the automatically determined parameters of the exposure operating mode to a physician as suggested or recommended parameters for the exposure operating mode. In other instances, the automatically determined parameters may be compared to parameters received manually via telemetry and, if differences exist or occur, a physician or patient may be notified and/or the manual parameters may be overridden by the automatically determined parameters.

Abstract: This disclosure describes techniques for automatically disabling an exposure mode that was enabled for operation in the presence of a disruptive energy field. For example, an implantable medical device (IMD) automatically disables the exposure operating mode when (i) the amount of time that has elapsed since enabling the IMD exceeds a threshold amount of time and (ii) a disruptive energy field is detected before the amount of time exceeds the threshold amount of time and the disruptive energy field is not currently detected. When either of these conditions is not met, the IMD continues to operate in accordance with the exposure operating mode.