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: An epicardial lead is passively fixed in a pericardial space by a passive fixation member. The passive fixation member extends from a distal portion of an epicardial lead and acts against a pericardial layer and an epicardial layer to hold the lead in place. The epicardial lead may include an electrode that is connected to a conductor that extends from a distal portion of the lead. In some embodiments the epicardial lead includes a material that promotes fibrosis to fix the lead to heart tissue. The passive fixation member may include a shocking coil.

Abstract: Methods, systems and devices described herein can be used for automatically adjusting one or more cardiac resynchronization therapy (CRT) pacing parameters (and more generally stimulation parameters), to achieve a long term reduction in left ventricular (LV) diastolic pressure (and more generally, preload) of a heart failure (HF) patient. A reduction in LV diastolic pressure is indicative of a reduction in preload (the force of blood the fills the left ventricle), which is typically indicative of an improvement in a patient's HF condition. In accordance with certain embodiments, when a set of stimulation parameters is tested, the set is tested for a period that is sufficiently long enough to allow the patient's compensatory mechanisms to react to the set of stimulation parameters and achieve a substantially steady-state LV diastolic pressure corresponding to the using the set of stimulation parameters.

Abstract: A leadless intra-cardiac medical device senses cardiac activity from multiple chambers and applies cardiac stimulation to at least one cardiac chamber and/or generates a cardiac diagnostic indication. The leadless device may be implanted in a local cardiac chamber (e.g., the right ventricle) and detect near-field signals from that chamber as well as far-field signals from an adjacent chamber (e.g., the right atrium).

Abstract: Embodiments of the present invention relate to implantable systems, and methods for use therewith, for assessing a patients' myocardial electrical stability. Implanted electrodes are used to obtain an electrogram (EGM) signal, which is used to identify periods when the patient experiences T-wave alternans. Additionally, the EGM signal is used to determine whether premature ventricular contractions (PVCs) cause phase reversals of the T-wave alternans. The patient's myocardial electrical stability is assessed based on whether, and in a specific embodiment the extent to which, PVCs cause phase reversals of the T-wave alternans. This abstract is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: A method for determining the cause of an irregularity in physiologic data collected by a medical device may include monitoring a collected physiologic characteristic of a patient through the physiologic data, detecting an irregularity in the physiologic data, monitoring position data of the patient, correlating the physiologic data with the position data, and determining the cause of the irregularity in the physiologic data based on correlation of the physiologic data with the position data.

Abstract: Anode foils suitable for use in electrolytic capacitors, including those having multiple anode configurations, have improved strength, reduced brittleness, and increased capacitance compared to conventional anode foils for electrolytic capacitors. Exemplary methods of manufacturing an anode foil suitable for use in an electrolytic capacitor include disposing a resist material in a predetermined pattern on an exposed surface of an anode foil substrate such that a first portion of the exposed surface of the anode foil substrate is covered by the resist material, and a second portion of the exposed surface remains uncovered; polymerizing the resist material; exposing at least the second portion of the exposed surface to one or more etchants so as to form a plurality of tunnels; stripping the polymerized resist material; and widening at least a portion of the plurality of tunnels. The resist material may be deposited, for example, by ink-jet printing, stamping or screen printing.

Abstract: Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart.

Abstract: A level shifter shifts the level of an input signal from a second voltage domain to a first voltage domain. To accommodate different input signal levels (e.g., including sub-threshold input signal levels) that may arise due to changes in the supply voltage for the second voltage domain, current for a latch circuit of the level shifter is limited based on the supply voltage for the second voltage domain. In this way, a drive circuit of the level shifter that controls the latch circuit based on the input signal is able to initiate a change of state of the latch circuit over a wide range of input signal levels.

Abstract: Techniques are provided for controlling spinal cord stimulation (SCS) or other forms of neurostimulation. Far-field cardiac electrical signals are sensed using a lead of the SCS device and neurostimulation is selectively delivering using a set of adjustable SCS control parameters. Parameters representative of cardiac rhythm are derived from the far-field cardiac electrical signals. The parameters representative of cardiac rhythm are correlated with SCS control parameters to thereby map neurostimulation control settings to cardiac rhythm parameters. The delivery of further neurostimulation is then controlled based on the mapping of neurostimulation control settings to cardiac rhythm parameters to, for example, address any cardiovascular disorders detected based on the far-field cardiac signals. In this manner, a closed loop control system is provided to automatically adjust SCS control parameters to respond to changes in cardiac rhythm such as changes associated with ischemia, arrhythmia or heart failure.

Abstract: Techniques are provided for use by implantable medical devices such as cardiac resynchronization therapy (CRT) devices for detecting pulmonary edema based on transthoracic impedance sensed using cardiac pacing/sensing leads, wherein detection can be performed while lead maturation occurs. Briefly, the implantable device determines whether the leads are within an initial post-implant interval following implant during which lead maturation generally occurs. The device then detects pulmonary edema or related medical conditions within the patient based on transthoracic impedance using a set of detection parameters adjusted for use during the post-implant interval. Thus, rather than “blanking” impedance data during lead maturation, the device instead detects and processes impedance during this period to identify possible episodes of pulmonary edema so that appropriate measures can be undertaken, such as delivery of warnings or titration of appropriate medications.

Abstract: A method and system are provided for characterizing chamber specific function. The method and system comprise collecting cardiac signals associated with asynchronous timing between first and second chambers of the heart; collecting dynamic impedance (DI) data along a chamber-specific function (CSF) vector to form a DI data set, the DI data set collected during a collection window that is temporally aligned based on a timing feature of interest (FOI); repeating the collection operations over multiple cardiac cycles (CC) to obtain an ensemble of DI data sets; and combining the ensemble of DI data sets to form a composite DI data set that is coupled to a chamber functional mechanic of interest (FMOI) associated with the first chamber and decoupled from functional mechanics associated with the second chamber; and analyzing the composite DI data set to obtain a CSF indicator associated with the chamber FMOI of the first chamber.

Abstract: A method and system are provided for determining fluid status with a central venous system of a heart. Dynamic impedance (DI) data and static impedance (SI) data are collected over multiple cardiac cycles (CC) for a persistent time period of interest (POI). The DI and SI data are collected along a central venous (CV) vector that extends through a superior vena cava (SVC). The DI and SI data are analyzed to obtain DI long-term variation (LTV) information and SI LTV information, respectively, and to detect whether the DI LTV information and the SI LTV information include decreasing persistent trends in the DI and SI data. When decreasing persistent trends are detected in the DI and SI data, an overload output is generated to indicate that the heart is experiencing a volume overload state. The DI and SI data represent a surrogate for central venous pressure.

Abstract: A method of determining pacing therapy for an individual patient including determining representative electromechanical physiologic characteristics for a plurality of normal patients having a range of anatomical dimensions and developing a plurality of normal templates. Each template indicates the representative electromechanical physiologic characteristics of a group of normal patients having similar anatomical dimensions.

Abstract: An implantable medical pulse generator is disclosed herein. The pulse generator is for administering electrotherapy via an implantable medical lead having a lead connector end on a proximal end of the lead. The pulse generator includes a can and a header coupled to the can. The header includes a first lead connector end receiving receptacle and a retainer configured to secure the lead connector end within the first receptacle. The retainer includes a member and a first collar, which is coaxially aligned with the first receptacle. The first collar includes an inner circumferential surface and a gap in the inner circumferential surface. The inner circumferential surface extends generally continuous and unbroken between a first face of the gap and a second face of the gap. The member is configured such that acting on the member causes a gap distance between the first face of the gap and second face of the gap to decrease, thereby reducing an inner circumferential diameter of the first collar.

Abstract: An apparatus and method for quantifying myocardial kinetics by positioning two sensors on a myocardial substrate site so that one sensor is directly opposing the other along a ventricular wall; tracking a relative displacement between the two sensors; and determining whether there is an infarct based on the tracked relative displacement.

Abstract: Techniques are provided for use with implantable medical devices such as pacemakers for optimizing interventricular (VV) pacing delays for use with cardiac resynchronization therapy (CRT). In one example, ventricular electrical depolarization events are detected within a patient in which the device is implanted. The onset of isovolumic ventricular mechanical contraction is also detected based on cardiomechanical signals detected by the device, such as cardiogenic impedance (Z) signals, S1 heart sounds or left atrial pressure (LAP) signals. Then, an electromechanical time delay (T_QtoVC) between ventricular electrical depolarization and the onset of isovolumic ventricular mechanical contraction is determined. VV pacing delays are set to minimize the time delay to the onset of isovolumic ventricular mechanical contraction. Various techniques for identifying the onset of isovolumic ventricular contraction based on Z, S1 or LAP or other cardiomechanical signals are described.

Abstract: An implantable medical device (IMD) may include a communication module, a therapy control module, a firmware control module, and a service application. The communication module is configured to wirelessly communicate over an RF link with an external device. The therapy control module is configured to deliver therapy to the patient, and may include a reprogrammable therapy logic circuit configured to operate the therapy control module in a reprogrammable mode of operation, and base-therapy state machine (BTSM) logic circuit configured to operate the therapy control module in a base therapy mode of operation. The firmware control module may include CPU and a memory. The service application may be stored in the memory. The firmware control module is configured to launch the service application, and the BTSM logic circuit provides a base level of sensing and pacing therapy while the communications module in parallel maintains the RF link with the external device.

Abstract: A method and system are provided to analyze valve related timing and monitor heart failure. The method and system comprise collecting cardiac signals associated with an atrial chamber of interest; collecting dynamic impedance (DI) data along an atria-function focused (AFF) vector to form a DI data set, the DI data set including information corresponding to a mechanical function (MF) of a valve associated with the atrial chamber of interest; identifying, from the cardiac signals, an intra-atrial conduction timing (IACT) associated with the atrial chamber of interest; estimating an MF landmark at which the mechanical function of the valve occurs based on the DI data set; analyzing a timing delay between the MF landmark and the IACT; and adjusting a therapy, based on the timing delay, to encourage atrial contribution to ventricular filling.

Abstract: Active rejection techniques are used to cancel MRI gradient signals in an implantable medical device. An active component placed in an input channel of the implantable medical device actively rejects MRI gradient signals received on the input channel. A sensing circuit that senses an external MRI gradient signal generates a control signal that controls the active component. For example, the control signal may be the inverse of the external MRI gradient signal. An active component that receives an input signal including a desired signal component (e.g., a cardiac signal) and an undesired MRI gradient signal component may thus use this control signal to reject the undesired MRI gradient signal component.