Abstract: In an implantable medical device for monitoring glucose concentration in the blood, a blood-glucose concentration analysis is performed using correlations of blood-glucose concentration with measures of metabolic oxygen consumption including oxymetric, and/or temperature. Analysis of electrocardiographic data is used in a parallel method to detect and/or confirm the onset and/or existence and/or extent of hypoglycemia and/or hyperglycemia. Blood-glucose concentration calculation is enhanced by using the combination of the oxygen metabolism analysis and electrocardiographic analysis.

Abstract: A medical device is provided that comprises a lead assembly. The lead assembly includes at least one intra-cardiac (IC) electrode, an extra-cardiac (EC) electrode and a subcutaneous remote-cardiac (RC) electrode. The IC electrode is configured to be located within the heart. The EC electrode is configured to be positioned proximate to at least one of a superior vena cava (SVC) and a left ventricle (LV) of a heart. The RC electrode is configured to be located remote from the heart. An extra-cardiac impedance (ECI) module is configured to measure extra-cardiac impedance along an ECI vector between the EC and RC electrodes to obtain ECI measurements. An arrhythmia monitoring module is configured to declare a potential atrial arrhythmia to be an atrial arrhythmia based on the hemodynamic performance determined from the ECI measurements. The hemodynamic performance assessment module is further enabled to compare a current ECI pattern with a prior baseline ECI waveform.

Abstract: Embodiments of the present invention relate to implantable systems, and methods for use therewith, for monitoring myocardial mechanical stability based on a signal that is indicative of mechanical functioning of a patient's heart for a plurality of consecutive beats. Certain embodiments use time domain techniques, while other embodiments use frequency domain techniques, to monitor myocardial mechanical stability. In certain embodiments the patient's heart is paced using a patterned pacing sequence that repeats every N beats. In other embodiments, the patient's heart need not be paced. This abstract is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: An implantable device monitors and treats heart failure, pulmonary edema, and hemodynamic conditions and in some cases applies therapy. In one implementation, the implantable device applies a high-frequency multi-phasic pulse waveform over multiple-vectors through tissue. The waveform has a duration less than the charging time constant of electrode-electrolyte interfaces in vivo to reduce intrusiveness while increasing sensitivity and specificity for trending parameters. The waveform can be multiplexed over multiple vectors and the results cross-correlated or subjected to probabilistic analysis or thresholding schemata to stage heart failure or pulmonary edema. In one implementation, a fractionation morphology of a sensed impedance waveform is used to trend intracardiac pressure to stage heart failure and to regulate cardiac resynchronization therapy. The waveform also provides unintrusive electrode integrity checks and 3-D impedancegrams.

Abstract: Techniques are provided for detecting and distinguishing stroke and cardiac ischemia within a patient using an implantable medical device. In one example, a preliminary indication of stroke is detected by a pacemaker or similar implantable device based on an analysis of features of an intracardiac electrogram (IEGM) sensed by the device. Exemplary IEGM features indicative of possible stroke include the onset of prominent U-waves, the onset of notched T-waves, and changes in ST segment duration or QT duration. Upon detection of a possible stroke, the device then detects one or more hemodynamic parameters that are typically affected by cardiac ischemia. Such hemodynamic parameters can include, e.g., cardiac contractility or stroke volume. The device then distinguishes stroke and cardiac ischemia from one another based on whether any changes detected in the hemodynamic parameters are consistent with cardiac ischemia.

Abstract: Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart.

Abstract: An exemplary method includes use of a multielectrode device that can help position a cardiac stimulation lead to an optimal site in the heart based at least in part on cardiac motion information acquired via the multielectrode device and one or more pairs of current delivery electrodes that establish potential fields (e.g., for use as a coordinate system). An exemplary mutlielectrode device may be a multielectrode catheter or a multifilar, electrode-bearing guidewire. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A method of identifying a potential cause of pulmonary edema is provided. The method includes obtaining one or more impedance vectors between predetermined combinations of the electrodes positioned proximate the heart. At least one of the impedance vectors is representative of a thoracic fluid level. The method also includes applying a stimulation pulse to the heart and sensing cardiac signals of the heart that are representative of an electrophysiological response to the stimulation pulse. The method further includes monitoring the cardiac signals and at least one of the impedance vectors with respect to time to identify the potential cause of pulmonary edema.

Abstract: An implantable system acquires intracardiac impedance with an implantable lead system. In one implementation, the system generates frequency-rich, low energy, multi-phasic waveforms that provide a net-zero charge and a net-zero voltage. When applied to bodily tissues, current pulses or voltage pulses having the multi-phasic waveform provide increased specificity and sensitivity in probing tissue. The effects of the applied pulses are sensed as a corresponding waveform. The waveforms of the applied and sensed pulses can be integrated to obtain corresponding area values that represent the current and voltage across a spectrum of frequencies. These areas can be compared to obtain a reliable impedance value for the tissue. Frequency response, phase delay, and response to modulated pulse width can also be measured to determine a relative capacitance of the tissue, indicative of infarcted tissue, blood to tissue ratio, degree of edema, and other physiological parameters.

Abstract: A method is disclosed that includes selecting an electrode configuration from a plurality of electrode configurations associated with electrodes of an implantable lead, sensing activity of the right ventricle and the left ventricle, determining an interval between sensed activity of the right ventricle and sensed activity of the left ventricle and determining whether the selected electrode configuration is suitable based at least in part on the interval. In one embodiment, an implantable device performs such a method to improve patient response to the CRT therapy, for example, by selecting a different electrode configuration if the current configuration is not suitable. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Techniques are provided for detecting stroke within a patient using an implantable medical device in conjunction with an external confirmation system. In one example, a preliminary detection of stroke is performed by a subcutaneous monitor based on an analysis of features of an electrocardiogram (ECG) sensed within the patient. Exemplary ECG features indicative of possible stroke include the onset of prominent U-waves, the onset of notched T-waves, and changes in ST segment duration or QT duration or dynamic trends in these parameters. The monitor transmits a signal indicative of possible stroke to a bedside monitor or other external system, which generates a stroke questionnaire for use in confirming the stroke. Family members or other caregivers input answers to the questionnaire into the external system, which confirms or disconfirms the stroke. Emergency personnel can be automatically notified.

Abstract: A system and method for treating an arrhythmia in a heart are provided. The system includes an electronic control unit configured to monitor movement of one or more position sensor over a period of time. The position sensors may, for example, comprise electrodes or coils configured to generate induced voltages and currents in the presence of electromagnetic fields. The positions sensors are in contact with portions of heart tissue and changes in position are representative of motion of that tissue. The electronic control unit is further configured to generate an indicator, responsive to the movements of the sensors over the period of time, of a characteristic of the heart affected by delivery of ablation energy to heart tissue. In this manner, the effectiveness and safety of cardiac tissue ablation for treatment of the arrhythmia can be assessed and a post-ablation therapy regimen determined.

Abstract: An exemplary method includes use of a multielectrode device that can help position a cardiac stimulation lead to an optimal site in the heart based at least in part on cardiac motion information acquired via the multielectrode device and one or more pairs of current delivery electrodes that establish potential fields (e.g., for use as a coordinate system). An exemplary mutlielectrode device may be a multielectrode catheter or a multifilar, electrode-bearing guidewire. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes delivering a cardiac resynchronization therapy using an atrio-ventricular delay and an interventricular delay, monitoring patient activity, optimizing the atrio-ventricular delay and the interventricular delay for a plurality of patient activity states to generate a plurality of optimal atrio-ventricular delays and a plurality of optimal interventricular delays, storing the optimal atrio-ventricular delays and the optimal interventricular delays in association with corresponding patient activity states, detecting a change in patient activity, adjusting an atrial pacing rate in response to the detected change in patient activity based at least in part on a heart failure status and setting the atrio-ventricular delay and the interventricular delay, in response to the detected change in patient activity, using a stored optimal atrio-ventricular delay that corresponds to the patient activity and a stored optimal interventricular delay that corresponds to the patient activity.

Abstract: A medical device is provided that comprises a lead assembly. The lead assembly includes at least one intra-cardiac (IC) electrode, an extra-cardiac (EC) electrode and a subcutaneous remote-cardiac (RC) electrode. The IC electrode is configured to be located within the heart. The EC electrode is configured to be positioned proximate to at least one of a superior vena cava (SVC) and a left ventricle (LV) of a heart. The RC electrode is configured to be located remote from the heart. An arrhythmia monitoring module is configured to analyze intra-cardiac electrogram (IEGM) signals from the at least one IC electrode to identify a potential atrial arrhythmia. An extra-cardiac impedance (ECI) module is configured to measure extra-cardiac impedance along an ECI vector between the EC and RC electrodes to obtain ECI measurements. The hemodynamic performance (HDP) assessment module is configured to determine a hemodynamic performance based on the ECI measurements.

Abstract: An exemplary method includes use of a multielectrode device that can help position a cardiac stimulation lead to an optimal site in the heart based at least in part on cardiac motion information acquired via the multielectrode device and one or more pairs of current delivery electrodes that establish potential fields (e.g., for use as a coordinate system). An exemplary multielectrode device may be a multielectrode catheter or a multifilar, electrode-bearing guidewire. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Implantable systems, and methods for use therein, perform at least one of a cardiac assessment and an autonomic assessment. Short-term fluctuations in PR intervals, that follow the premature contractions in the ventricles, are monitored. At least one of a cardiac assessment and an autonomic assessment is performed based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles. This can include assessing a patient's risk of sudden cardiac death (SCD), assessing a patient's autonomic tone and/or detecting myocardial ischemic events based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles.

Abstract: An implantable system acquires intracardiac impedance with an implantable lead system. In one implementation, the system generates frequency-rich, low energy, multi-phasic waveforms that provide a net-zero charge and a net-zero voltage. When applied to bodily tissues, current pulses or voltage pulses having the multi-phasic waveform provide increased specificity and sensitivity in probing tissue. The effects of the applied pulses are sensed as a corresponding waveform. The waveforms of the applied and sensed pulses can be integrated to obtain corresponding area values that represent the current and voltage across a spectrum of frequencies. These areas can be compared to obtain a reliable impedance value for the tissue. Frequency response, phase delay, and response to modulated pulse width can also be measured to determine a relative capacitance of the tissue, indicative of infarcted tissue, blood to tissue ratio, degree of edema, and other physiological parameters.

Abstract: An implantable system acquires intracardiac impedance with an implantable lead system. In one implementation, the system generates frequency-rich, low energy, multi-phasic waveforms that provide a net-zero charge and a net-zero voltage. When applied to bodily tissues, current pulses or voltage pulses having the multi-phasic waveform provide increased specificity and sensitivity in probing tissue. The effects of the applied pulses are sensed as a corresponding waveform. The waveforms of the applied and sensed pulses can be integrated to obtain corresponding area values that represent the current and voltage across a spectrum of frequencies. These areas can be compared to obtain a reliable impedance value for the tissue. Frequency response, phase delay, and response to modulated pulse width can also be measured to determine a relative capacitance of the tissue, indicative of infarcted tissue, blood to tissue ratio, degree of edema, and other physiological parameters.

Abstract: A cardiac analysis system is provided that includes an implantable medical device (IMD), at least one sensor, and an external device. The IMD has electrodes positioned proximate to a heart that sense first cardiac signals of the heart and associated with a clinical ventricular tachycardia (VT) event and second cardiac signals associated with an induced VT event. The sensor measures first and second cardiac parameters of the heart associated with the clinical and induced VT events, respectively. The external device is configured to receive the first and second cardiac signals associated with the clinical and the induced VT events and the first and second cardiac parameters associated with the clinical and the induced VT events. The external device compares the first and second cardiac signals and compares the first and second cardiac parameters to determine if the clinical and induced VT events are a common type of VT event.