Abstract: Pattern classification techniques are provided for use with an implantable medical device for detecting cardiac ischemia substantially in real-time. Values representative of morphological features of electrical cardiac signals are detected by the implantable medical device. Then, a determination is made as to whether the patient is subject to an on-going episode of cardiac ischemia by applying the values to a pattern classifier configured to identify patterns representative of cardiac ischemia. In one example, the determination is made substantially in real-time by the device itself based on the IEGM signals it detects. In other examples, the IEGM signals are relayed promptly to a bedside monitor or other external device, which analyzes the signals using the pattern classifier to detect ischemia. Therapy may be applied in response to cardiac ischemia. For example, if the implanted device is equipped with a drug pump, appropriate medications may be administered such as anti-thrombolytics.

Abstract: An implantable medical device with a notification system. The device monitors itself and an implantee for one or more condition indicating notification and delivers the notification at a time the patient is determined to be wakeful and, optionally, at relative rest. The notification can be repeated periodically until acknowledged by the user or the system is evaluated and reprogrammed by the physician. A user input can be included to provide the device confirmation of receipt of the notification as well as to delay delivery of any indicated subsequent notifications. The notification is provided without requiring any additional or special dedicated hardware.

Abstract: An exemplary method includes detecting arrhythmia, detecting myocardial ischemia, determining whether the myocardial ischemia comprises local ischemia or global ischemia and, in response to the determining, calling for delivery of either a local ischemic anti-arrhythmia therapy or a global ischemic anti-arrhythmia therapy. Various 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 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: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. In one example, the emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles or by combining near-field signals sensed in the atria with near-field signals sensed in the ventricles. In another example, the emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal sensed using a single pair of electrodes, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal or by attenuating atrial portions of a cross-chamber signal relative to ventricular portions to the same signal.

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 tachyarrhythmia and also for preventing T-wave oversensing using a narrowband bradycardia filter in combination with a narrowband tachycardia filter. In some embodiments, a separate wideband filter is also exploited. In one illustrative example, ventricular tachycardia (VT) is detected by: detecting a preliminary indication of VT using signals filtered by the bradycardia filter and, in response, confirming the detection of VT using signals filtered by the tachycardia filter. That is, the bradycardia filter, traditionally used only to detect bradycardia, is additionally used to provide a preliminary indication of VT. The tachycardia filter is then activated to confirm the detection of VT before therapy is delivered. In this manner, the tachycardia filter need not run continuously, but is instead activated only when there is some indication of possible VT, and hence power is saved.

Abstract: An exemplary method includes providing an overdrive pacing rate and, determining an incidence limit for incidence of intrinsic atrial activity events, as well as the incidence of intrinsic atrial activity events The exemplary, method further includes comparing the incidence of intrinsic atrial activity events to the incidence limit and, based at least on the comparing, deciding whether to adjust the overdrive pacing rate. According to this exemplary method, the incidence limit is optionally a function of overdrive pacing rate. Another exemplary method includes determining a dwell limit wherein the dwell limit is optionally a function of overdrive pacing rate. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A method for operating an implantable medical device includes determining the difference of the absolute value of the voltage of a test QRS complex and the voltage of a baseline QRS template at a plurality of corresponding sample points and detecting ischemia if the sum of the differences at the plurality of sample points is greater than an ischemia detection threshold.

Abstract: An implantable cardiac stimulating device employs different post-ventricular atrial refractory periods for different types of ventricular events, such as a sensed ventricular event and a paced ventricular event. A controller facilitates selection or adjustment by remote programming of two different post-ventricular atrial blanking intervals that are invoked depending upon the type of ventricular event. A set of discrete blanking interval values may be available for programming the different blanking intervals, and a search routine may be executed to systematically apply the different blanking interval values and determine a suitable value by determining whether far-field R-waves are detected after expiration of each applied blanking interval value.

Abstract: A method and apparatus for treating an arrhythmia is provided. The method includes the steps of: (a) sensing at least one electrical signal from the patient's heart; (b) calculating a frequency spectrum of each electrical signal; (c) calculating a center frequency for each frequency spectrum; and (d) selecting an electro-therapy for delivery to the patient's heart based on the center frequency. The electro-therapy can be a pre-programmed anti-tachycardia pacing (ATP) therapy, a shock therapy, or no therapy at all. The method is performed through the use of an implantable cardioverter defibrillator (ICD). Also provided is a method of determining the optimal location to deliver the electro-therapy.

Abstract: A method and apparatus for treating an arrhythmia is provided. The method includes the steps of: (a) sensing at least one electrical signal from the patient's heart; (b) calculating a frequency spectrum of each electrical signal; (c) calculating a center frequency for each frequency spectrum; and (d) selecting an electro-therapy for delivery to the patient's heart based on the center frequency. The electro-therapy can be a pre-programmed anti-tachycardia pacing (ATP) therapy, a shock therapy, or no therapy at all. The method is performed through the use of an implantable cardioverter defibrillator (ICD). Also provided is a method of determining the optimal location to deliver the electro-therapy.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. In one example, the emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles or by combining near-field signals sensed in the atria with near-field signals sensed in the ventricles. In another example, the emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal sensed using a single pair of electrodes, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal or by attenuating atrial portions of a cross-chamber signal relative to ventricular portions to the same signal.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. In one example, the emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles or by combining near-field signals sensed in the atria with near-field signals sensed in the ventricles. In another example, the emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal sensed using a single pair of electrodes, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal or by attenuating atrial portions of a cross-chamber signal relative to ventricular portions to the same signal.

Abstract: An implantable cardiac system including an implantable cardiac stimulation device provides a heart activity signal of a heart facilitating measurement of slowly changing electrogram features. The system comprises at least one implantable electrode arrangement that senses cardiac electrical activity and provides an intracardiac electrogram signal, a first high pass filter that filters the electrogram and an equalizer that filters the filtered electrogram signal. The equalizer has a transfer function that is non-decreasing for frequencies up to a lower frequency breakpoint that is less than the upper frequency breakpoint, decreasing for frequencies between the lower frequency breakpoint and the upper frequency breakpoint, and generally flat for frequencies above the upper frequency breakpoint through a bandpass region of interest.

Abstract: Techniques are provided for overdrive pacing the ventricles using a pacemaker wherein an increase in an overdrive pacing rate is performed primarily to achieve a high degree of rate smoothing. The ventricles are paced at an overdrive pacing rate selected to permit the detection of the least some intrinsic ventricular pulses and then the overdrive pacing rate is dynamically adjusted based on the detected intrinsic ventricular pulses. In one example, an increase in the ventricular overdrive rate is performed only in response to detection of at least two intrinsic ventricular beats within a predetermined search period. If at least two intrinsic ventricular beats are not detected within the search period, the overdrive pacing rate is decreased.

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: A cardiac stimulation device includes a sensing unit for monitoring the electrical activity of a heart and a controller configured to predict the onset of an arrhythmia of the heart. The controller calculates a statistical indicia relating to the immediate past four R—R intervals in the form of a sliding average thereof. Upon the prediction that the risk of the onset of an arrhythmia is high, the controller compares the current value of the R—R interval to the indicia. If the current value of the R—R interval exceeds the indicia by a predetermined amount, the controller causes a high amplitude pacing pulse to be delivered to a selected cardiac site in an attempt to forestall the initiation of ventricular fibrillation.