Abstract: An exemplary method includes acquiring patient activity information and/or nerve activity information, detecting one or more episodes of atrial fibrillation, associating the information with atrial fibrillation and, upon occurrence of particular patient activity and/or nerve activity, calling for delivery of an anti-atrial fibrillation therapy. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An implantable system applies tiered antitachycardia pacing (ATP) that may be combined with pre-pulsing therapy in order to reduce pain. In one implementation, an exemplary system applies a progression of increasingly potent pacing vectors, progressing in an initial tier from small electrodes inside the heart to later tiers that increasingly use a large electrode surface outside the heart. In the latter tiers, a pre-pulse may be added prior to each ATP pulse to reduce the sensation of pain.

Abstract: Techniques are provided for improving cardiac output and also suppressing certain forms of apnea/hypopnea within a patient using an implantable medical device, such as a pacemaker or ICD. In one example, a selected pacing parameter—usually the pacing rate—is temporarily altered by an amount sufficient to elevate cardiac output, the elevation in cardiac output being eventually reduced by intrinsic compensatory mechanisms within the patient. The pacing parameter is then temporarily reset for a duration sufficient to allow the compensatory mechanisms to return toward a previous state so as to permit a subsequent alteration in the pacing parameter to again elevate cardiac output. The pacing parameter is repeatedly altered and reset so as to achieve an overall increase in cardiac output despite the intrinsic compensatory mechanisms. The increase in cardiac output is often sufficient to suppress certain forms of apnea/hypopnea, particularly apnea/hypopnea arising from Cheyne-Stokes Respiration (CSR).

Abstract: An exemplary method includes calling for delivery of energy to one or more electrodes positionable proximate to an autonomic pathway to alter tone of the geniglossus muscle. Such a method may maintain or alter upper airway patency and, in turn, prevent or alleviate obstructive apnea. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An implantable system applies tiered antitachycardia pacing (ATP) that may be combined with pre-pulsing therapy in order to reduce pain. In one implementation, an exemplary system applies a progression of increasingly potent pacing vectors, progressing in an initial tier from small electrodes inside the heart to later tiers that increasingly use a large electrode surface outside the heart. In the latter tiers, a pre-pulse may be added prior to each ATP pulse to reduce the sensation of pain.

Abstract: An exemplary method includes delivering a maintenance therapy that aims to prevent occurrence of apnea, sensing information, based at least in part on the information, determining if apnea exists and, if apnea exists, delivering a termination therapy that aims to terminate the apnea. An exemplary implantable device includes an input for information pertaining to respiration and control logic to call for overdrive pacing at a first rate that aims to minimize occurrence of a respiratory condition, to analyze the information for occurrence of the respiratory condition and, upon occurrence of the respiratory condition, to call for overdrive pacing at a higher rate. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are provided for treating periodic breathing, such as Cheyne-Stokes Respiration, using an implantable medical system. In one technique, diaphragmatic stimulation is delivered during a hyperpnea phase of periodic breathing via electrical stimulation of the phrenic nerves. Diaphragmatic stimulation is synchronized with intrinsic inspiration so as to increase the amplitude of diaphragmatic contraction during inspiration. This tends to decrease intrathoracic pressure leading to occlusion of the respiratory airway. Occlusion reduces actual ventilation during hyperpnea, thus reducing the cyclic blood chemistry imbalance that sustains periodic breathing so as to either mitigate periodic breathing or eliminate it completely. In another technique, respiration is instead inhibited during the hyperpnea phase of periodic breathing by blocking phrenic nerve signals to the extent necessary to reduce ventilation to terminate periodic breathing or at least mitigate its severity.

Abstract: An exemplary method includes sensing respiratory information related to tidal volume, based at least in part on the respiratory information, determining if tidal volume is less than a limit and, if the tidal volume is less than the limit, calling for diaphragm activation at a stimulation power based on a nondecreasing monotonic relationship with respect to increasing tidal volume. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Techniques are provided for detecting the onset of an episode of apnea/hypopnea substantially in real-time. A moving threshold is generated based on recent respiration cycles and differences are accumulated between amplitudes of new respiration cycles and the moving threshold. Apnea/hypopnea is then detected based upon a comparison of the accumulated differences against a fixed threshold. The technique exploits the fact that many episodes of hypopnea begin with a sharp drop in respiration and many episodes of apnea are preceded by a sharp drop in respiration. By accumulating differences between new respiration amplitudes and a short term moving average, any sharp drop in respiration is thereby promptly detected. In many cases, by the time the amplitudes of individual respiration cycles drop to levels directly indicative of apnea/hypopnea, the episode of apnea/hypopnea will have already been detected based upon the sudden sharp drop in respiration amplitude and therapy will have already been initiated.

Abstract: An exemplary method includes sensing respiratory information related to tidal volume, based at least in part on the respiratory information, determining if the tidal volume is less than a limit and, if the tidal volume is less than the limit, calling for diaphragm activation at a stimulation power based on a nonincreasing monotonic relationship with respect to decreasing difference between the tidal volume and the limit. Various other technologies are also disclosed.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are provided for treating periodic breathing, such as Cheyne-Stokes Respiration, using an implantable medical system. In one technique, diaphragmatic stimulation is delivered during a hyperpnea phase of periodic breathing via electrical stimulation of the phrenic nerves. Diaphragmatic stimulation is synchronized with intrinsic inspiration so as to increase the amplitude of diaphragmatic contraction during inspiration. This tends to decrease intrathoracic pressure leading to occlusion of the respiratory airway. Occlusion reduces actual ventilation during hyperpnea, thus reducing the cyclic blood chemistry imbalance that sustains periodic breathing so as to either mitigate periodic breathing or eliminate it completely. In another technique, respiration is instead inhibited during the hyperpnea phase of periodic breathing by blocking phrenic nerve signals to the extent necessary to reduce ventilation to terminate periodic breathing or at least mitigate its severity.

Abstract: An exemplary method includes delivering stimulation according to one or more stimulation parameters to cause contraction of the diaphragm, monitoring chest activity related to respiration and, in response to the monitoring, adjusting one or more of the one or more stimulation parameters during contraction of the diaphragm and continuing the delivering. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An implantable cardiac device is programmed to promote intrinsic rhythm of a patient's heart to alleviate orthostatic hypotension. In one implementation, the cardiac device is set in a reduced rate mode while the patient is in a less upright position, such as when resting in a supine position. If the patient is in intrinsic rhythm when transitioning to a more upright position, the cardiac device disables administration of any increased pacing rate for a programmed duration. In this manner, the patient will experience a more natural variation in heart rate during transition from the less upright posture to the more upright posture (e.g., from supine to sitting or standing). On the other hand, if the patient is being paced during the transition, the cardiac device administers an increased base rate or triggers an orthostatic response algorithm.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.

Abstract: Techniques are provided for treating periodic breathing, such as Cheyne-Stokes Respiration, using an implantable medical system. In one technique, diaphragmatic stimulation is delivered during a hyperpnea phase of periodic breathing via electrical stimulation of the phrenic nerves. Diaphragmatic stimulation is synchronized with intrinsic inspiration so as to increase the amplitude of diaphragmatic contraction during inspiration. This tends to decrease intrathoracic pressure leading to occlusion of the respiratory airway. Occlusion reduces actual ventilation during hyperpnea, thus reducing the cyclic blood chemistry imbalance that sustains periodic breathing so as to either mitigate periodic breathing or eliminate it completely. In another technique, respiration is instead inhibited during the hyperpnea phase of periodic breathing by blocking phrenic nerve signals to the extent necessary to reduce ventilation to terminate periodic breathing or at least mitigate its severity.