摘要:
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.
摘要:
An exemplary method includes determining an atrial to ventricular activation time for a right ventricle; determining an atrial to ventricular activation time for a left ventricle; and determining a pacing sequence that paces the right ventricle prior to activation of the left ventricle if the time for the right ventricle exceeds the time for the left ventricle or that paces the left ventricle prior to activation of the right ventricle if the time for the left ventricle exceeds the time for the right ventricle, wherein, in the pacing sequence, pacing of the prior, paced ventricle occurs at a time based at least in part on a difference between the time for the right ventricle and the time for the left ventricle and an atrio-ventricular delay limit. Various other exemplary methods, devices and/or systems are also disclosed.
摘要:
An implantable cardiac stimulation lead system for use with a stimulation device includes a lead body preferably having an outer diameter of less than 4 French and formed of a biocompatible material having a Young's modulus of at least 20,000 pounds per square inch. In the lead body, an inner insulator is composed of a suitable polymer such as PTFE or ETFE with an outer peripheral surface formed with a helical groove containing a conductor extending between a proximal connector and a distal tip electrode, and an outer insulator composed of polyurethane or silicone rubber or a combination thereof is positioned around the inner insulator. The lead system may be formed with a lumen for receiving a guidewire longitudinally through the lead body. A pair of insulated conductors may be received in the helical groove, one extending to the distal tip electrode, the other extending to a ring electrode proximally spaced from the distal tip electrode.
摘要:
An exemplary method includes selecting a cross-correlation frequency having an associated cross-correlation period, detecting and binning a heart rate in a heart rate bin, detecting and binning an activity state in an activity state bin, repeating the detecting and binning a heart rate and the detecting and binning an activity state during a cross-correlation period, and summing the products a bin count of the heart rate bins and a bin count of the activity state bins to provide a cross-correlation index for the cross-correlation period. Other exemplary algorithms, methods, devices, systems, etc., are also disclosed.
摘要:
Techniques are provided for predicting the onset of a heart condition within a patient based on impedance measurements. Briefly, overloads in fluid levels in the thorax and in ventricular myocardial mass within the patient are detected based on impedance signals sensed using implanted electrodes. The onset of certain heart conditions is then predicted based on the overloads. For example, pulmonary edema arising due to diastolic heart failure is predicted based on the detection of on-going overloads in both fluid levels and ventricular mass. Ventricular hypertrophy is detected based on an on-going ventricular mass overload without a sustained fluid overload. Various other heart conditions may also be predicted based on specific combinations of recent or on-going overloads. Evoked response is exploited to corroborate the predictions. Appropriate warning signals are generated and preemptive therapy is initiated.
摘要:
Exemplary methods and devices for determining respiratory and/or autonomic characteristics based at least in part on atrioventricular conduction and/or one or more atrioventricular conduction interval times. Other methods, devices and/or systems are also disclosed.
摘要:
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.
摘要:
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.
摘要:
Exemplary methods and devices for analyzing intracardiac electrocardiograms (IEGMs) using statistical analysis (e.g., histograms, etc.), ensemble averaging and/or an ensemble average. Various methods and/or devices are suitable for use with atrial and/or ventricular pacing therapies. Other methods, devices and/or systems are also disclosed.
摘要:
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.