Abstract: A coupled/paired stimulus pulse is delivered to the heart at an inter-pulse interval following one of i) detection of an intrinsic depolarization or ii) delivery of a primary stimulus pulse. Capture resulting from the coupled/paired stimulus pulse is sensed for. In response to capture by a coupled/paired stimulus pulse, the inter-pulse interval is incrementally decreased by a first amount until there is no capture by a coupled/paired stimulus pulse. In response to no capture by a coupled/paired stimulus pulse, the inter-pulse interval is incrementally increased by a second amount greater than the first amount, until capture by a coupled/paired stimulus pulse is detected. Once capture is again detected, paired/coupled pacing is delivered at the inter-pulse interval which resulted in capture for a predetermined period of time or until loss of capture occurs.

Abstract: Techniques are described for use with an implantable cardiac stimulation device for performing paired/coupled pacing either alone or in conjunction with dynamic overdrive/underdrive pacing. In one technique, dynamic overdrive/underdrive pacing is delivered to the ventricles using paired pulses during an episode of atrial fibrillation. The use of paired pulses during dynamic ventricular overdrive/underdrive pacing helps lower and stabilize the ventricular rate to thereby reduce the risk of a ventricular arrhythmia. In another technique, the inter-pulse interval between paired pulses is optimized to lengthen the resulting refractory period to improve hemodynamics. Preferably, the optimized inter-pulse interval is used when applying dynamic ventricular overdrive/underdrive pacing with paired pulses so that the benefits of both techniques are obtained. The optimization technique is also applicable to setting the coupling interval for use with coupled pacing.

Abstract: Techniques for detecting tachyarrhythmia and also for preventing T-wave oversensing use signals filtered by a narrowband bradycardia filter in combination with signals filtered by a narrowband tachycardia filter. A separate wideband filter may also be used.

Abstract: Techniques are provided for use in a pacemaker or implantable cardioverter/defibrillator (ICD) for distinguishing cardiac ischemia from other conditions affecting the morphology of electrical cardiac signals sensed within a patient, such as hypoglycemia, hyperglycemia or other systemic conditions. In one example, the device detects changes in morphological features of cardiac signals indicative of possible cardiac ischemia within the patient, such as changes in ST segment elevation within an intracardiac electrogram (IEGM). The device determines whether the changes in the morphological features are the result of spatially localized changes within a portion of the heart and then distinguishes cardiac ischemia from other conditions affecting the morphology of electrical cardiac signals based on that determination. In another example, the device exploits the interval between the peak of a T-wave (Tmax) and the end of the T-wave (Tend).

Abstract: Techniques for detecting tachyarrhythmia and also for preventing T-wave oversensing use signals filtered by a narrowband bradycardia filter in combination with signals filtered by a narrowband tachycardia filter. A separate wideband filter may also be used.

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: An implanted cardiac rhythm management device is disclosed that is operative to detect myocardial ischemia. This is done by evaluating electrogram features to detect an electrocardiographic change; specifically, changes in electrogram segment during the early part of an ST segment. The early part of the ST segment is chosen to avoid the T-wave.

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: Methods and systems are presented for using an ICD to detect myocardial ischemia. One such method includes sensing via an implantable cardiac-rhythm-management device (ICRMD) a signal indicative of cardiac pressure; determining via a processor associated with the ICRMD, a derivative signal that is a first derivative of the sensed signal; measuring via the processor, a maximum positive value of the derivative signal; measuring via the processor, a maximum negative value of the derivative signal; and indicating via the processor, an ischemia based on a comparison of a ratio of the maximum positive value to the maximum negative value with a predetermined value.

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: An implanted cardiac rhythm management device is disclosed that is operative to detect myocardial ischemia. This is done by evaluating electrogram features to detect an electrocardiographic change; specifically, changes in electrogram segment during the early part of an ST segment. The early part of the ST segment is chosen to avoid the T-wave.

Abstract: An implanted cardiac rhythm management device is disclosed that is operative to detect myocardial ischemia. This is done by evaluating electrogram features to detect an electrocardiographic change; specifically, changes in electrogram segment during the early part of an ST segment. The early part of the ST segment is chosen to avoid the T-wave.

Abstract: A coupled/paired stimulus pulse is delivered to the heart at an inter-pulse interval following one of i) detection of an intrinsic depolarization or ii) delivery of a primary stimulus pulse. Capture resulting from the coupled/paired stimulus pulse is sensed for. In response to capture by a coupled/paired stimulus pulse, the inter-pulse interval is incrementally decreased by a first amount until there is no capture by a coupled/paired stimulus pulse. In response to no capture by a coupled/paired stimulus pulse, the inter-pulse interval is incrementally increased by a second amount greater than the first amount, until capture by a coupled/paired stimulus pulse is detected. Once capture is again detected, paired/coupled pacing is delivered at the inter-pulse interval which resulted in capture for a predetermined period of time or until loss of capture occurs.

Abstract: Methods and systems are presented for using an ICD to detect myocardial ischemia. One such method includes sensing via an implantable cardiac-rhythm-management device (ICRMD) a signal indicative of cardiac pressure; determining via a processor associated with the ICRMD, a derivative signal that is a first derivative of the sensed signal; measuring via the processor, a maximum positive value of the derivative signal; measuring via the processor, a maximum negative value of the derivative signal; and indicating via the processor, an ischemia based on a comparison of a ratio of the maximum positive value to the maximum negative value with a predetermined value.

Abstract: Methods and systems are presented for using an ICD to detect myocardial ischemia. In one embodiment, a method includes sensing a signal indicative of cardiac pressure, measuring a height of the sensed signal at a peak amplitude of the sensed signal, and measuring a duration of the sensed signal. The method further includes indicating an ischemia based on a comparison of a ratio of the height to the duration with a predetermined value. In another embodiment, a method includes sensing a signal indicative of cardiac pressure, determining a derivative signal that is a first derivative of the sensed signal, measuring a maximum positive value of the derivative signal, and measuring a maximum negative value of the derivative signal. The method further includes indicating an ischemia based on a comparison of a ratio of the maximum positive value to the maximum negative value with a predetermined value.

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 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 implantable cardiac lead system suitable for placement in the coronary sinus region of the heart. The lead system comprises a lead having two or more non-helical bends in its distal portion. The two or more non-helical bends cooperate to prevent the lead from dislodgment or displacement inside the coronary sinus. The lead system may further comprise a stylet suitable for steering the lead into at least one of the coronary sinus vein, great cardiac vein, left marginal vein, left posterior ventricular vein, and small cardiac vein. The stylet is tapered in its distal portion to provide enhanced maneuverability and steerability inside the coronary sinus region. The lead system may also comprise an introducer which aids in introducing the lead into the heart.