Abstract: An example medical device includes a plurality of electrodes, therapy delivery circuitry, and processing circuitry configured to control the therapy delivery circuitry to deliver electrical stimulation to an intercostal nerve of a patient via at least two of the plurality of electrodes, wherein the electrical stimulation is delivered with stimulation parameters configured to suppress ventricular tachyarrhythmia of the patient, wherein the stimulation parameters comprise a stimulation frequency less than or equal to 40 hertz (Hz).

Abstract: An example medical device includes a plurality of electrodes, therapy delivery circuitry, and processing circuitry configured to control the therapy delivery circuitry to deliver electrical stimulation to an intercostal nerve of a patient via at least two of the plurality of electrodes, wherein the electrical stimulation is delivered with stimulation parameters configured to suppress ventricular tachyarrhythmia of the patient, wherein the stimulation parameters comprise a stimulation frequency less than or equal to 40 hertz (Hz).

Abstract: An optical perfusion sensor may monitor blood oxygen saturation of blood-perfused tissue, which may be referred to as tissue perfusion, until a tissue perfusion value is within a threshold range of a reference value, and, in some examples, for at least a minimum period of time. The tissue perfusion value may indicate an absolute blood oxygen saturation level or a relative change in blood oxygen saturation level. The reference value may be, for example, determined by an oxygen (O2) variation index that indicates a change in blood oxygen saturation of tissue. In some examples, the optical perfusion sensor may be activated upon detecting a cardiac event, such as a cardiac arrhythmia. In addition, in some examples, cardiac signal monitoring may be activated upon detecting a threshold change in tissue perfusion.

Abstract: A reflectance optical perfusion sensor may include at least one light source and a plurality of detector elements arranged in a planar or nonplanar configuration, such as a three-dimensional array. The detector elements may sense light emitted by the at least one light source and reflected by a blood mass of a patient, such as blood within a blood vessel. In some examples, the detector elements may be arranged such that photodetection surfaces of at least two of the detector elements are nonparallel. In addition to or instead of the nonplanar arrangement of detector elements, an optical perfusion sensor may include a detector array including a plurality of detector elements at least partially surrounding a light source. Varying the location and orientations of detector elements may help increase a quantity of light emitted by the at least one light source and reflected toward the optical perfusion sensor by blood.

Abstract: Techniques for performing a lead integrity test during a suspected tachyarrhythmia are described. An implantable medical device (IMD) may perform the test prior to delivering a therapeutic shock to treat the suspected tachyarrhythmia and, in some cases, may withhold the shock based on the test. In some examples, the IMD measures an impedance of a lead a plurality of times during the suspected tachyarrhythmia. In some examples, the IMD measures the impedance a plurality of times between two sensed events of the suspected tachyarrhythmia. The IMD or another device may determine a variability of, or otherwise compare, the measured impedances to evaluate the integrity of the lead. Instead of or in addition to withholding a shock, the IMD or another device may change a sensing or stimulation vector of the IMD, or provide an alert to a user, if the integrity test indicates a possible lead integrity issue.

Abstract: An optical perfusion sensor may monitor blood oxygen saturation of blood-perfused tissue, which may be referred to as tissue perfusion, until a tissue perfusion value is within a threshold range of a reference value, and, in some examples, for at least a minimum period of time. The tissue perfusion value may indicate an absolute blood oxygen saturation level or a relative change in blood oxygen saturation level. The reference value may be, for example, determined by an optical oxygenation (O2) variation index that indicates a change in blood oxygen saturation of tissue. In some examples, an operation of a cardiac signal sensing module may be controlled based upon detecting a threshold change in tissue perfusion. For example, the cardiac signal sensing module may be activated upon detecting a threshold change in tissue perfusion.

Abstract: Techniques for performing a lead integrity test during a suspected tachyarrhythmia are described. An implantable medical device (IMD) may perform the test prior to delivering a therapeutic shock to treat the suspected tachyarrhythmia and, in some cases, may withhold the shock based on the test. In some examples, the IMD measures an impedance of a lead a plurality of times during the suspected tachyarrhythmia. In some examples, the IMD measures the impedance a plurality of times between two sensed events of the suspected tachyarrhythmia. The IMD or another device may determine a variability of, or otherwise compare, the measured impedances to evaluate the integrity of the lead. Instead of or in addition to withholding a shock, the IMD or another device may change a sensing or stimulation vector of the IMD, or provide an alert to a user, if the integrity test indicates a possible lead integrity issue.

Abstract: Techniques for performing a lead integrity test during a suspected tachyarrhythmia are described. An implantable medical device (IMD) may perform the test prior to delivering a therapeutic shock to treat the suspected tachyarrhythmia and, in some cases, may withhold the shock based on the test. In some examples, the IMD measures an impedance of a lead a plurality of times during the suspected tachyarrhythmia. In some examples, the IMD measures the impedance a plurality of times between two sensed events of the suspected tachyarrhythmia. The IMD or another device may determine a variability of, or otherwise compare, the measured impedances to evaluate the integrity of the lead. Instead of or in addition to withholding a shock, the IMD or another device may change a sensing or stimulation vector of the IMD, or provide an alert to a user, if the integrity test indicates a possible lead integrity issue.

Abstract: An optical perfusion sensor may monitor blood oxygen saturation of blood-perfused tissue, which may be referred to as tissue perfusion, until a tissue perfusion value is within a threshold range of a reference value, and, in some examples, for at least a minimum period of time. The tissue perfusion value may indicate an absolute blood oxygen saturation level or a relative change in blood oxygen saturation level. The reference value may be, for example, determined by an oxygen (O2) variation index that indicates a change in blood oxygen saturation of tissue. In some examples, the optical perfusion sensor may be activated upon detecting a cardiac event, such as a cardiac arrhythmia. In addition, in some examples, cardiac signal monitoring may be activated upon detecting a threshold change in tissue perfusion.

Abstract: A reflectance optical perfusion sensor may include at least one light source and a plurality of detector elements arranged in a planar or nonplanar configuration, such as a three-dimensional array. The detector elements may sense light emitted by the at least one light source and reflected by a blood mass of a patient, such as blood within a blood vessel. In some examples, the detector elements may be arranged such that photodetection surfaces of at least two of the detector elements are nonparallel. In addition to or instead of the nonplanar arrangement of detector elements, an optical perfusion sensor may include a detector array including a plurality of detector elements at least partially surrounding a light source. Varying the location and orientations of detector elements may help increase a quantity of light emitted by the at least one light source and reflected toward the optical perfusion sensor by blood.

Abstract: An optical perfusion sensor may monitor blood oxygen saturation of blood-perfused tissue, which may be referred to as tissue perfusion, until a tissue perfusion value is within a threshold range of a reference value, and, in some examples, for at least a minimum period of time. The tissue perfusion value may indicate an absolute blood oxygen saturation level or a relative change in blood oxygen saturation level. The reference value may be, for example, determined by an optical oxygenation (O2) variation index that indicates a change in blood oxygen saturation of tissue. In some examples, an operation of a cardiac signal sensing module may be controlled based upon detecting a threshold change in tissue perfusion. For example, the cardiac signal sensing module may be activated upon detecting a threshold change in tissue perfusion.

Abstract: Techniques for performing a lead integrity test during a suspected tachyarrhythmia are described. An implantable medical device (IMD) may perform the test prior to delivering a therapeutic shock to treat the suspected tachyarrhythmia and, in some cases, may withhold the shock based on the test. In some examples, the IMD measures an impedance of a lead a plurality of times during the suspected tachyarrhythmia. In some examples, the IMD measures the impedance a plurality of times between two sensed events of the suspected tachyarrhythmia. The IMD or another device may determine a variability of, or otherwise compare, the measured impedances to evaluate the integrity of the lead. Instead of or in addition to withholding a shock, the IMD or another device may change a sensing or stimulation vector of the IMD, or provide an alert to a user, if the integrity test indicates a possible lead integrity issue.