Abstract: Constant voltage or current is applied to high-voltage leads to determine impedance across medical device leads. Thyristors are used for upper switching components in an H-bridge. Current is sourced into a thyristor's gate from a ground-referenced source. This current then passes from the gate to the cathode and out to the patient. By keeping the current sufficiently low, the thyristors will not conduct from the anode to the cathode. Current passes through the thyristor, lead and patient and is sensed as it returns from the other lead. The sensed current is used to regulate the injected current. Pulses of constant current on the order of tens of milliamperes can be injected and the resulting voltage can be measured. Alternatively, a constant voltage can be applied and the resulting current can be measured to determine lead impedance.

Abstract: An implantable lead includes a lead body, having a distal end and a proximal end, configured to be implanted in a patient, and a connector provided at the proximal end. A load detection assembly is provided on the lead body, wherein the load detection assembly includes a housing that holds a sensor and a load transfer element. The load transfer element engages the sensor and conveys a force induced on the load transfer element to the sensor. Optionally, the housing may isolate the sensor from lateral forces and the load transfer element may only convey, to the sensor, longitudinal forces that are directed in a predetermined single direction. For example, the load transfer element may only convey, to the sensor, longitudinal forces that are directed perpendicular to a surface of the sensor.

Abstract: 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.

Abstract: A method of etching a foil for use in an electrolytic capacitor utilizes a nanoimprinted optic to control the etch pattern. The optic is formed by creating a self-assembled monolayer (SAM) of hemispheres onto the surface of an optical quartz substrate. A laser is directed onto the optic while the foil underlies the optic, and the concentrated light source is used to effectively image an array of submicron spots. The resulting spots allow for controlled initiation of etch tunnels during a subsequent electrochemical etch of the foil, with the purpose of ultimately increasing foil capacitance through the increased surface area.

Abstract: A morphology discrimination scheme extracts shape characteristics from cardiac signals and identifies an associated cardiac condition based on the shape characteristics. For example, internal data structures may be updated to match the shape characteristics of a known condition (e.g., a patient's normal sinus rhythm). Similarly acquired shape characteristics obtained in conjunction with a later event (e.g., QRS complexes acquired during a tachycardia episode) may be compared with the previously stored shape characteristics to characterize the later event. In some aspects the shape characteristics relate to inflection points of cardiac signals.

Abstract: Techniques are provided for use with an implantable cardiac stimulation device equipped for multi-site left ventricular (MSLV) pacing using a multi-pole LV lead. In one example, referred to herein as QuickStim, cardiac pacing configurations are optimized based on an assessment of hemodynamic benefit and device longevity. In another example, referred to herein as QuickSense, cardiac sensing configurations are optimized based on sensing profiles input by a clinician. Various virtual sensing channels are also described that provide for the multiplexing or gating of sensed signals. Anisotropic oversampling is also described.

Abstract: An RF protection circuit mitigates potentially adverse effects that may otherwise result from electromagnetic interference (e.g., due to MRI scanning of a patient having an implanted medical device). The RF protection circuit may comprise a voltage divider that is deployed across a pair of cardiac electrodes that are coupled to internal circuitry of the implantable medical device. Each leg of the voltage divider may be referenced to a ground of the internal circuit, whereby the different legs are deployed in parallel across different circuits of the internal circuitry. In this way, when an EMI-induced (e.g., MRI-induced) signal appears across the cardiac electrodes, the voltages appearing across these circuits and the currents flowing through these circuits may be reduced. The RF protection circuit may be used in an implantable medical device that employs a relatively low capacitance feedthrough to reduce EMI-induced (e.g., MRI-induced) current flow in a cardiac lead.

Abstract: A lead connector end is disclosed herein. The lead connector end may include a generally cylindrical body of unitary construction. The unitary construction may include an electrically non-conductive material extending between three ring contacts imbedded in the electrically non-conductive material. The three ring contacts are offset from each other along a longitudinal length of the unitary body. An electrical conductor extends between two of the three ring contacts and is recessed within an outer circumferential surface of the generally cylindrical body of unitary construction. The electrical conductor is electrically connected to the two of the three ring contacts and forms an integral shunt between the two of the three ring contacts.

Abstract: Techniques are provided for use with an implantable medical device for assessing left ventricular (LV) sphericity and atrial dimensional extent based on impedance measurements for the purposes of detecting and tracking heart failure and related conditions such as volume overload or mitral regurgitation. In some examples described herein, various short-axis and long-axis impedance vectors are exploited that pass through portions of the LV for the purposes of assessing LV sphericity. In other examples, impedance measurements taken along a vector between a right atrial (RA) ring electrode and an LV electrode implanted near the atrioventricular (AV) groove are exploited to assess LA extent, biatrial extent or mitral annular diameter. The assessment techniques can be employed alone or in conjunction with other heart failure detection techniques, such as those based on left atrial pressure (LAP.

Abstract: Various techniques are provided for calibrating and estimating left atrial pressure (LAP) using an implantable medical device, based on impedance, admittance or conductance parameters measured within a patient. In one example, default conversion factors are exploited for converting the measured parameters to estimates of LAP. The default conversion factors are derived from populations of patients. In another example, a correlation between individual conversion factors is exploited to allow for more efficient calibration. In yet another example, differences in thoracic fluid states are exploited during calibration. In still yet another example, a multiple stage calibration procedure is described, wherein both invasive and noninvasive calibration techniques are exploited. In a still further example, a therapy control procedure is provided, which exploits day time and night time impedance/admittance measurements.

Abstract: Techniques are described for generating diagnostic information to aid in determining whether cardiac ischemia within a patient is clinically actionable. In one example, a pacemaker or implantable cardioverter/defibrillator (ICD) detects information pertaining to arrhythmia precursors and to episodes of sustained arrhythmias, as well as information pertaining to episodes of cardiac ischemia. The implanted device then correlates the arrhythmia precursors and the sustained arrhythmias with the episodes of cardiac ischemia so as to generate diagnostics permitting a physician reviewing the diagnostics to determine whether the ischemia is clinically actionable. In some implementations, the diagnostics are instead generated by an external system based on raw data provided by the implanted device. In some implementations, the device itself determines whether the ischemia is clinically actionable and automatically controls therapy or generates warning signals accordingly.

Abstract: An implantable medical device (IMD) is provided comprising inputs configured to be coupled to leads having electrodes thereon, wherein combinations of the electrodes are associated with respective active sensing vector. The IMD further comprises an impedance measurement module to collect multiple measured impedances between corresponding combinations of the electrodes. The IMD further includes an impedance derivation module to calculate a derived impedance for at least one pseudo sensing vector based on the measured impedances, wherein the pseudo sensing vector extends to or from at least one pseudo sensing site.

Abstract: Systems and methods are provided for allowing an implantable medical device, such as pacemaker, to properly sense electrophysiological signals and hemodynamic signals within a patient during a magnetic resonance imaging (MRI) procedure. Systems and methods are also provided for allowing the implantable medical device to transmit the sensed data to an external monitoring system during the MRI procedure so that attending medical personnel can closely monitor the health of the patient and the operation of the implantable device during the MRI. These improvements provide the attending personnel with information needed to determine whether the MRI should be suspended in response to induced tachyarrhythmias or other adverse conditions within the patient.

Abstract: An implanted cardioverter defibrillator (ICD) delivers an electrical therapy signal to the heart of a patient. When ventricular fibrillation or another condition of the heart requiring high voltage therapy is sensed, the therapy signal is delivered to the heart. When a partial short-circuit or other low impedance condition occurs, an over-current protection circuit will stop delivery of a shocking pulse. The ICD will then reduce the voltage of the shocking pulse and try again to deliver electrical therapy. This process is repeated until a voltage level is found that is able to deliver the electrical therapy without causing an over-voltage condition. Alternate lead configurations may also be tried in an attempt to find a signal path that is not affected by the low impedance or short-circuit condition.

Abstract: Evaluation of an implanted electrical lead condition includes comparing electrogram template features with test electrogram features. The evaluating also includes determining the implanted electrical lead condition based solely on the electrogram comparison. The compared test electrogram features and template electrogram features may be atrial amplitudes and ventricular amplitudes. The sensing may be with a quad polar lead. The compared test electrogram features and electrogram template features may account for different patient postures and/or may account for respiration modulation.

Abstract: An exemplary implantable microarray device includes an inlet for a body fluid, a plurality of individual reaction cell arrays where each reaction cell array includes a series of reaction cells configured to receive the body fluid, a sensor array to sense a reaction result for an individual reaction cell array where the reaction result corresponds to a reaction between the body fluid and at least one reagent in each of the reaction cells of the individual reaction cell array and a positioning mechanism to position an individual reaction cell array with respect to the sensor array. Various other exemplary technologies are also disclosed.

Abstract: Techniques are provided for use with implantable medical devices such as pacemakers for optimizing atrioventricular (AV) pacing delays for use with cardiac resynchronization therapy (CRT). In one example, the end of atrial mechanical contraction and the onset of isovolumic ventricular mechanical contraction are detected within a patient in which the device is implanted based on cardiomechanical signals, such as cardiogenic impedance (Z) signals, S1 heart sounds or left atrial pressure (LAP) signals. Then, a cardiomechanical time delay (MC_AV) between the end of atrial contraction and the onset of isovolumic ventricular contraction is determined. AV pacing delays are set based on MC_AV to align the end an atrial kick with the onset of isovolumic ventricular contraction. Thereafter, pacing is controlled based on the AV pacing delays.

Abstract: To provide radio-frequency (RF) bandstop filtering within an implantable lead for use in reducing lead heating during magnetic resonance imaging (MRI) procedures, parallel inductive-capacitive (LC) filters are provided within the lead. In one example, the ring electrode of the lead is configured to function as one of the capacitive elements of the parallel LC filter to help provide LC bandstop filtering along the ring conductor of the lead. In another example, capacitive plates are provided that sandwich an inductor mounted near the tip of the lead to provide parallel LC bandstop filtering along the tip conductor of the lead.

Abstract: Disclosed herein is a magnetic navigation enabled tool configured for the delivery of an implantable medical lead. The tool includes a tubular body, a sensor and a conductor. The tubular body includes a distal end, a proximal end, an inner layer including an outer circumferential surface, a lumen inward of the inner layer, and an outer layer over the outer circumferential surface of the inner layer. The sensor is on the tubular body near the distal end. The conductor extends from the sensor coil towards the proximal end imbedded in the inner layer.

Abstract: The disclosure relates in some aspects to an implantable pressure sensor and a method of measuring pressure. In some embodiments pressure may be measured through the use of an implantable lead incorporating one or more pressure sensors. In some aspects a pressure sensor is implemented in a micro-electromechanical system (“MEMS”) that employs direct mechanical sensing. A biocompatible material is attached to one or more portions of the MEMS sensor to facilitate implant in a body of a patient. The MEMS sensor may thus be incorporated into an implantable lead for measuring blood pressure in, for example, one or more chambers of the patient's heart.