Abstract: Techniques are provided for use with implantable medical devices for addressing encapsulation effects, particularly in the detection of cardiac decompensation events such as heart failure (HF) or cardiogenic pulmonary edema (PE.) In one example, during an acute interval following device implant, cardiac decompensation is detected using heart rate variability (HRV), ventricular evoked response (ER) or various other non-impedance-based parameters that are insensitive to component encapsulation effects. During the subsequent chronic interval, decompensation is detected using intracardiac or transthoracic impedance signals. In another example, the degree of maturation of encapsulation of implanted components is assessed using impedance frequency-response measurements or based on the frequency bandwidth of heart sounds or other physiological signals.

Abstract: Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias.

Abstract: An apparatus for and method of measuring pressure through a septum in a patient's heart. A lead inserted into the right side of a heart is routed through the septum to gain access to the left side of the heart. The lead includes a mounting mechanism that secures the lead to one or both sides of the septal walls. The lead also includes one or more sensors for measuring cardiac pressure on the left side of the heart and, as necessary, the right side of the heart.

Abstract: An exemplary method includes emitting radiation subcutaneously; sensing at least some of the emitted radiation as reflected cutaneously; detecting an abnormal physiologic condition; and, based at least in part on the sensing, adjusting a stimulation therapy to treat the detected abnormal condition. In such a method, the abnormal condition may be an abnormal cardiac condition, an abnormal neural condition or other condition. Various other methods, devices, systems, etc., are also disclosed.

Abstract: An implantable medical device (“IMD”) processes and analyzes valuable clinical information regarding cardiac performance. A database or correlator is pre-customized to the specific patient, by correlating signals received by a remote accelerometer associated with heart movements with accurate heart sounds recorded from a microphone to provide a more effective and customized basis for estimating heart sound. The information is then used to better control an implantable medical device.

Abstract: A multi-layer capacitor includes a first capacitor layer and a second capacitor layer adjacent and substantially parallel to the first capacitor layer. The second capacitor layer has a surface area that is less than the surface area of the first capacitor layer.

Abstract: In specific embodiments, a method for estimating a patient's central arterial blood pressure (CBP) for use with an implantable system, comprises (a) using an implanted sensor at a first site to obtain a first signal indicative of changes in arterial blood volume at the first site, the first site being along one or more peripheral arterial structures of the patient, (b) using an implanted sensor at a second site to obtain a second signal indicative of changes in arterial blood volume at the second site, the second site being a distance from the first site downstream along an arterial path of the peripheral arterial structure of the patient, and (c) using implanted electrodes to obtain a signal indicative of electrical activity of the patient's heart.

Abstract: Systems and methods are provided for reducing heating within pacing/sensing leads of a pacemaker or implantable, cardioverter-defibrillator that occurs due to induced loop currents during a magnetic resonance imaging (MRI) procedure, or in the presence of other sources of strong radio frequency (RF) fields. For example, bipolar coaxial leads are described herein wherein the ring conductor of the lead is disconnected from the ring electrode in response to detection of MRI fields so as to convert the ring conductor into an RF shield for shielding the inner tip conductor of the lead so as to reduce the strength of loop currents induced therein and hence reduce tip heating.

Abstract: Embodiments of the present invention are directed to implantable systems, and methods for use therewith, that monitor and modify a patient's arterial blood pressure without requiring an intravascular pressure transducer. In accordance with an embodiment, for each of a plurality of periods of time, there is a determination one or more metrics indicative of pulse arrival time (PAT), each of which are indicative of how long it takes for the left ventricle to generate a pressure pulsation that travels from the patient's aorta to a location remote from the patient's aorta. Based on the one or more metrics indicative of PAT, the patient's arterial blood pressure is estimated. Changes in the arterial blood pressure are monitored over time. Additionally, the patient's arterial blood pressure can be modified by initiating and/or adjusting pacing and/or other therapy based on the estimates of the patient's arterial blood pressure and/or monitored changes therein.

Abstract: A non-implanted system receives, from an implantable cardiac device implanted within a patient, data corresponding to detected potential episodes of tachycardia. A representation of the data corresponding to the detected potential episodes of tachycardia is displayed to a user, and the user that observes the displayed representation of the data is allowed to enter a user diagnosis for each of the detected potential episodes of tachycardia. The non-implanted system simulates how the implantable cardiac device can use its discriminators to produce device diagnoses, based on the data for the detected potential episodes of tachycardia, including how adjustments to the discriminators affect how the device diagnoses match the user diagnoses. Thereafter, the non-implanted system can reprogram the implantable cardiac device to increase a likelihood that future device diagnoses produced by the implantable cardiac device would more closely match future user diagnoses produced by the user.

Abstract: Selection of an appropriate rate programming control (RPC) setting in an implantable medical device (IMD), uses analysis of VA coupling surrogate conditions. The VA coupling surrogate conditions are derived from signals such as cardiogenic impedance, blood pressure, and the pulsatile components of PPG. By analyzing a waveform of the measured surrogate condition, the IMD estimates wall stiffness, through the slope of the waveform, and peripheral arterial pressure, through the reflection time between the main wave and reflection wave of the waveform. These values are plotted against each other on a VA coupling coordinate plane. Based on the location and orientation of the resulting VA coupling plot, the IMD selects an appropriate RPC setting.

Abstract: A method for reducing occurrences of atrial arrhythmias includes obtaining measures indicative of atrial pressure of a patient, and monitoring for a change in the measures indicative of atrial pressure that is indicative of an increased vulnerability to an atrial arrhythmia. In response to detecting the change in the measures indicative of atrial pressure that is indicative of the increased vulnerability to an atrial arrhythmia, pacing therapy that is adapted to reduce atrial pressure and thereby reduce vulnerability to an atrial arrhythmia is selectively delivered. Additionally, or alternatively, pacing therapy is adjusted to reduce atrial pressure and thereby reduce vulnerability to an atrial arrhythmia.

Abstract: Techniques are provided for detecting stroke within a patient using an implantable medical device in conjunction with an external confirmation system. In one example, a preliminary detection of stroke is performed by a subcutaneous monitor based on an analysis of features of an electrocardiogram (ECG) sensed within the patient. Exemplary ECG features indicative of possible stroke include the onset of prominent U-waves, the onset of notched T-waves, and changes in ST segment duration or QT duration or dynamic trends in these parameters. The monitor transmits a signal indicative of possible stroke to a bedside monitor or other external system, which generates a stroke questionnaire for use in confirming the stroke. Family members or other caregivers input answers to the questionnaire into the external system, which confirms or disconfirms the stroke. Emergency personnel can be automatically notified.

Abstract: Disclosed herein is an implantable medical lead. In one embodiment, the lead includes a ring electrode, a tip electrode, first and second helically wound coaxial conductor coils, and a distal coil transition. The coils extend between the proximal and distal ends of the lead. The distal coil transition is proximal to the ring electrode and near the distal end and is where the first coil transitions from being outside the second coil proximal of the distal coil transition to being inside the second coil distal of the distal coil transition.

Abstract: Techniques are provided for use with an implantable medical device for assessing stroke volume or related cardiac function parameters such as cardiac output based on impedance signals obtained using hybrid impedance configurations that exploit a multi-pole cardiac pacing/sensing lead implanted near the left ventricle. In one example, current is injected between a large and stable reference electrode and a ring electrode in the RV. The reference electrode may be, e.g., a coil electrode implanted within the superior vena cava (SVC). Impedance values are measured along a set of different sensing vectors between the reference electrode and each of the electrodes of the multi-pole LV lead. Stroke volume is then estimated and tracked within the patient using the impedance values. In this manner, a hybrid impedance detection configuration is exploited whereby one vector is used to inject current and other vectors are used to measure impedance.

Abstract: A ventricular rate based on first candidate waveforms and second candidate waveforms within sensed ventricular waveforms is compared to an atrial rate. If the ventricular rate exceeds the atrial rate, the first candidate waveforms and second candidate waveforms are compared to a ventricular polarization complex template to obtain a first morphology indicator and a second morphology indicator. If a morphology match inconsistency is present, the amount by which the ventricular rate exceeds the atrial rate is compared to a threshold. If the threshold is exceeded, high-ventricular-rate therapy to the heart is inhibited. The ventricular polarization complex template may be a QRS-complex template, in which case a match inconsistency is present if each of the first candidate waveforms and the second candidate waveforms do not match the QRS-complex template.

Abstract: A method for accessing a target site in the body by transferring a guidewire from an initial insertion site on the body to a different insertion site on the body is provided. In one aspect, a method for transferring a medical device or component, such as a sensor lead, from an initial insertion site to another insertion site is also provided. A guidewire of sufficient length, pliancy and deformability to perform a transfer from one insertion site to another insertion site is provided. In one aspect, the guidewire comprises a removable core mandrel to increase rigidity, facilitate insertion and/or improve steerability. A kit or system, comprising introducers, guidewires and catheters for performing a guidewire or device transfer is also provided.

Abstract: Systems, devices and methods of monitoring blood flow velocity are disclosed herein. For example, one method of monitoring blood flow velocity includes: locating a blood flow velocity sensor near the ostium in the coronary sinus; and sensing towards a portion of the aorta. A second example method includes: locating a blood flow velocity sensor in a vein; and sensing towards an adjacent artery. A third example method includes: locating a blood flow velocity sensor near the tricuspid valve; and sensing towards a tricuspid valve annulus. A fourth example method includes: locating a blood flow velocity sensor right ventricular outflow tract; and sensing towards a portion of the aorta. A fifth example method includes: locating a blood flow velocity sensor in the great cardiac vein; and sensing towards a left anterior descending artery. A sixth example method includes: locating a blood flow velocity sensor in the right atrial appendage; and sensing towards a portion of the aorta.

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: A device, such as an implantable cardiac device, and method for switching between arrhythmia prevention modes is disclosed. The method includes monitoring an electrocardiogram (EGM) of the heart, determining whether the heart is in a normal sinus rhythm or in an abnormal rhythm, delivering pacing pulses at a first rate to either an atrium or a ventricle when the heart is in a normal sinus rhythm, and delivering pacing pulses to a ventricle at a second rate when the heart is in an abnormal rhythm, such as an atrial arrhythmia. The first rate is selected to minimize the occurrence of premature ventricular contractions, and the second rate is selected to both minimize the occurrence of premature ventricular contractions and minimize the occurrence of premature conducted beats.