48 results about "Conduction delay" patented technology

A system and method for estimating optimal atrioventricular delay values for use in pacing the ventricles. Both the intrinsic inter-atrial conduction delay and the intrinsic atrioventricular conduction delay are determined for the patient and then the preferred atrioventricular pacing delay is derived therefrom. By taking into account intrinsic inter-atrial delay along with intrinsic atrioventricular delay, a more reliable estimate of the true optimal atrioventricular delay values for the patient can be achieved than with techniques that only take into account intrinsic atrioventricular delay values. In one example, the technique uses intracardiac electrogram (IEGM) signals and surface electrocardiogram (EKG) signals and hence can be performed by an external programmer without requiring Doppler echocardiography or other cardiac performance monitoring techniques. In another example, wherein the implanted device is equipped with a coronary sinus lead, the technique uses only IEGM signals and hence can be performed by the device itself.

Techniques are provided for use with implantable cardiac stimulation devices equipped for multi-site left ventricular (MSLV) cardiac pacing. Briefly, intraventricular and interventricular conduction delays are detected for paced cardiac events. Maximum pacing time delays are determined for use with MSLV pacing where the maximum pacing time delays are set based on the conduction delays to values sufficient to avoid capture problems due to wavefront propagation, such as fusion or lack of capture. MSLV pacing delays are then set to values no greater than the maximum pacing delays and cardiac resynchronization therapy (CRT) is delivered using the MSLV pacing delays. In an example where an optimal interventricular pacing delay (VV) is determined in advance using intracardiac electrogram-based or hemodynamic-based optimization techniques, the optimal value for VV can be used as a limiting factor when determining the maximum MSLV pacing time delays.

Techniques are provided for estimating electrical conduction delays with the heart of a patient based on measured immittance values. In one example, impedance or admittance values are measured within the heart of a patient by a pacemaker or other implantable medical device, then used by the device to estimate cardiac electrical conduction delays. A first set of predetermined conversion factors may be used to convert the measured immittance values into conduction delay values. In some examples, the device then uses the estimated conduction delay values to estimate LAP or other cardiac pressure values. A second set of predetermined conversion factors may be used to convert the estimated conduction delays into pressure values. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP.

Techniques are provided for estimating left atrial pressure (LAP) or other cardiac performance parameters based on measured conduction delays. In particular, LAP is estimated based interventricular conduction delays. Predetermined conversion factors stored within the device are used to convert the various the conduction delays into LAP values or other appropriate cardiac performance parameters. The conversion factors may be, for example, slope and baseline values derived during an initial calibration procedure performed by an external system, such as an external programmer. In some examples, the slope and baseline values may be periodically re-calibrated by the implantable device itself. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP or other cardiac performance parameters. Still further, techniques are described for estimating conduction delays based on impedance or admittance values and for tracking heart failure therefrom.

Techniques are provided for estimating left atrial pressure (LAP) or other cardiac performance parameters based on measured conduction delays. In particular, LAP is estimated based interventricular conduction delays. Predetermined conversion factors stored within the device are used to convert the various the conduction delays into LAP values or other appropriate cardiac performance parameters. The conversion factors may be, for example, slope and baseline values derived during an initial calibration procedure performed by an external system, such as an external programmer. In some examples, the slope and baseline values may be periodically re-calibrated by the implantable device itself. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP or other cardiac performance parameters. Still further, techniques are described for estimating conduction delays based on impedance or admittance values and for tracking heart failure therefrom.

Techniques are provided for use by implantable medical devices for controlling ventricular pacing using a multi-pole left ventricular (LV) lead. In one example, a single “V sense” test is performed to determine intrinsic interventricular conduction time delays (Δn) between the RV electrode and each of the LV electrodes of the multi-pole lead. Likewise, a single “RV pace” test is performed to determine paced interventricular conduction time delays (IVCD_RLn) between the RV electrode and each of the LV electrodes. A set of “LV pace” tests is then performed to determine paced interventricular conduction time delays (IVCD_LRn) between individual LV electrodes and the RV electrode. Optimal or preferred interventricular pacing delays are determined using the intrinsic interventricular conduction delay (Δn) values and a set of interventricular correction terms (εn) determined from the results of the RV pace test and the set of LV pace tests. With these techniques, overall test time can be reduced.

A methods and devices for capture detection are based on sensing a propagated depolarization from a contralateral cardiac chamber. An intersite sensing interval is determined based on an intersite pacing delay and an intersite conduction delay associated with first and second pacing sites. Pacing pulses are delivered to the first pacing site and the second pacing site, the pacing pulses separated in time by the intersite pacing delay. An intersite sensing interval is timed. The process includes sensing, during the intersite sensing interval, at the first pacing site for a depolarization propagated to the first pacing site from the second pacing site. It a depolarization propagated from the second pacing site is not sensed, then capture of the first and second pacing sites is detected.

An LED tube lamp is disclosed. The LED tube lamp includes a lamp tube, a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal, a rectifying circuit coupled to the first external connection terminal and the second external connection terminal and configured to rectify the external driving signal to produce a rectified signal, a filtering circuit coupled to the rectifying circuit and configured to filter the rectified signal to produce a filtered signal, an LED module coupled to the filtering circuit and configured to receive the filtered signal for emitting light; and a conduction-delaying circuit coupled to the rectifying circuit and comprising a conduction-delaying device, wherein the conduction-delaying circuit is configured such that when the external driving signal is initially input to the LED tube lamp, the conduction-delaying device is in an open-circuit state, and then the conduction-delaying device will enter a conducting state when voltage across the conduction-delaying device exceeds the conduction-delaying device's trigger voltage value, wherein the conducting state of the conduction-delaying device causes the LED module to conduct current for emitting light.