Abstract: A method and device for transmitting a signal in an implantable medical device that includes a control unit and a first electrode and a second electrode positioned along a lead body. A connector block is positioned along an upper portion of a housing portion of the control unit, and a connector is positioned at a proximal portion of the lead body and is insertable within the connector block. A third electrode having a conductive element is positioned along the control unit in close proximity adjacent to the connector. The control unit transmits a signal between the first electrode and the second electrode and determines an alternate transmission path of the signal between the third electrode and one or both of the first electrode and the second electrode in response to the signal not being effectively transmitted between the first electrode and the second electrode.

Abstract: A method and apparatus for cardiac pacing are provided in which pacing pulses are delivered at an increased rate in response to a detected intrinsic heart rate drop and a special rate drop response detection scheme is temporarily disabled until an intrinsic heart rate exceeds a predetermined threshold value. If the pacing rate reaches the lower pacing rate without sensing intrinsic activity, heart rate drop detection remains disabled and lower rate pacing continues. Rate drop detection is re-enabled whenever sufficient sensed intrinsic activity indicates that a sudden intrinsic rate drop could occur again. Thus, the subsequent reduction in heart rate requiring therapy is declared only if a sensed intrinsic heart rate drops from above an intermediate value (herein defined as a re-enable rate) that is set above the lower pacing rate and an upper pacing rate.

Abstract: According to the present invention, discrete measurements of fluid pressure development (and derivatives thereof) are used in optimizing hemodynamics for cardiac resynchronization therapy (CRT) delivery and multiple chamber cardiac pacing, and in enhancing hemodynamics in the event of a sub-optimal left-side lead placement. For example, such diverse pressure measurements include: maximum positive or negative dP/dt values, ePAD, RV systolic, RV diastolic, pulse pressure, and the like. According to the present invention, on a periodic basis or upon demand one or more cardiac pacing intervals are iteratively cycled through a predetermined range and the resulting pressure measurements stored for comparison. The cardiac pacing intervals are then adjusted based at least in part upon the most appropriate, or desirable, measured hemodynamics of the patient. The present invention may be implemented as computer readable instructions executed by a microprocessor-based implantable medical device.

Abstract: Techniques are described for estimating a rate of blood flow from a heart, such as a stroke volume or a cardiac output, as a function of a pressure in the heart. A pressure monitor may measure pressure values, and identify the times at which pressure values and valve opening and closing occur. The pressure monitor may estimate a velocity-time function as a function of the measured pressures and identified times, and may calculate a velocity-time integral by integrating the velocity-time function. The pressure monitor may also calculate an estimated velocity-time integral directly as a function of the measured pressures and the identified times. The pressure monitor may calculate the stroke volume or cardiac output using the velocity-time integral. The pressure monitor may control a delivery of therapy by an implantable medical device as a function of the stroke volume or cardiac output.

Abstract: Echogenic devices, and methods of making and using such devices, are disclosed. In one aspect, the devices include a porous polymeric material that is preparable by extracting a phase separated composition. In another aspect, the echogenic devices include a polymeric composition having porous particles therein. Preferably the devices are medical devices.

Abstract: Triggers and noise should be available as information in recorded electrograms in memories of implantable medical devices. Particularly where the recording of electrogram data is done in the far field, there will be considerable noise and the interpretation of ECG's reproduced from such recorded data will benefit from the storing of information regarding contemporaneous noise. By storing contemporaneous trigger data and noise data directly in the ECG data, recordings of the ECG data become more useful for physician use when played back through an external display system with minimal loss of ECG data, since out of range values are employed for the noise and trigger information and this non-ECG data is limited in size to no longer than individual point values of the ECG signal.

Abstract: Techniques for detecting coagulum formation on an ablation electrode make use of an ablation electrode that is connected to a radio-frequency (RF) generator capable of applying a small amount of RF energy that is not cell destructive. The temperature at the ablation electrode can be precisely measured using a thermosensor incorporated within the ablation electrode. Before and after actual ablation, a low, non-cell destructing (non-ablating) amount of RF energy is generated at the ablation electrode. If no coagulum has formed during actual ablation, the temperature increase during this test application will be similar before and after the ablation attempt. If coagulum has formed during the actual ablation, however, the temperature increase during the test application after ablation will be significantly higher.

Abstract: A capacitor in an implantable medical device is provided. The capacitor having an anode, a cathode including a conductive coating, and an electrolyte disposed and in contact between the anode and the cathode. The conductive coating is composed of a chemisorbed conductive layer that is interposed between a metal substrate and a layer including a mix of activated carbon with a metal-oxide and electrolyte disposed and in contact between the anode and the cathode.

Abstract: A pacing method and apparatus includes providing an AV interval initiated by occurrence of either an atrial paced or sensed event. A ventricular safety pacing window is defined. In one embodiment, ventricular events are sensed at only one ventricular side and if a ventricular event is sensed during the ventricular safety pacing window, then a commitment is made to delivery of ventricular stimulus only to the one ventricular side of the patient's heart where the ventricular event is sensed. Further, in another embodiment, sensing of ventricular events may occur at both ventricular sides during the ventricular safety pacing window. If a ventricular event is sensed during the ventricular safety pacing window at a first ventricular side, then commitment is made to delivery of ventricular stimulus to at least the first ventricular side.

Abstract: The present invention provides a method and apparatus for detecting magnetic fields in implantable medical devices. The apparatus includes a sensor adapted to provide at least one signal proportional to at least one vector component of a magnetic field. The apparatus further includes a circuit adapted to receive the signal and perform a predetermined action when a predetermined quantity exceeds a predetermined threshold value.

Abstract: In general, the invention is directed to monitoring fluid retention that may accompany congestive heart failure and pulmonary edema. A medical device, such as an implanted pacemaker or an external defibrillator, senses electrical signals associated with the periodic depolarization and re-polarization of a heart. The device processes the electrical signals to obtain one or more “cardiac parameters,” which reflect pulmonary edema. By monitoring the cardiac parameters, the device monitors pulmonary edema. Cardiac parameters comprise the amplitude of the QRS complex, the integral of the QRS complex, or the integral of the QRST segment and the like. When the device detects fluid buildup, the device may respond by taking remedial action and/or generating an alert.

Abstract: The operational and functional aspects of one or more IMDs is controlled by physiological data acquired from an external device. Various externally deployed devices collect vital signals for transmission to the IMD. Upon receipt of the signals the IMD cooperatively modifies therapy and diagnostic procedures to be substantially compliant with the received signals. Further, the IMD may store some of the signals for future follow-up or patient data management as needed.

Abstract: Implantable medical devices (IMDs) and components, including flat electrolytic capacitors and methods of making and using same, particularly an improved electrolytic capacitor fabricated of an electrode stack assembly comprising a plurality of capacitor layers stacked in registration upon one another. Each capacitor layer comprises a valve metal cathode layer having a cathode tab, a valve metal anode layer having an anode tab, and a separator layer located between the cathode layers. The anode layer is assembled from a plurality of valve metal anode sheets that are etched and anodized, stacked side-by-side, and electrically and mechanically joined together by laser weld beads. A valve metal anode tab having a thickness equal to one or more anode sheet is inserted into a tab notch in one or more stacked anode sheet and joined to the anode sheet stack by laser welding the tab and sheet edges together.

Abstract: A communication system is provided which permits of communication between an deployed implantable medical device (IMD) and a large-scale powerful computer capable of manipulating complex nonlinear modeling of physiologic systems, and also capable of accounting for large amounts of historical data from a particular patient or a cohort group for improved modeling and predictive power, which may be expected to lead to improved patient outcomes. A deployed IMD may be polled by a routing instrument external to the host patient, and data may be received by wireless communication. This data may be transmitted to a central large-scale or other relatively powerful computer for processing according to an appropriate model. A treatment or instruction regimen, as well as appropriate firmware or software upgrades, may then be transmitted to the routing instrument for immediate or eventual loading into the IMD via wireless communication.

Abstract: An electrochemical cell and corresponding electrode assembly are described in which an alkali metal anode and a cathode assembly are wound together in a unidirectional winding having substantially straight sides such that the winding will fit into a prismatic cell. The anode and cathode are preferably arranged in the winding to provide for even utilization of reactive material during cell discharge by placing cathode and anode material in close proximity throughout the electrode assembly in the proportions in which they are utilized. An anode current collector having a length or height shorter than at least one of the length or height of the cathode current collector or alkali metal strips operatively associated with the anode current collector is also described.

Abstract: A feature named “atrial tracking recovery” (ATR) provides for restoring delivery of cardiac pacing therapy upon identification of an atrial refractory sense-ventricular sense (AR-VS) pattern of cardiac activity. In one embodiment, such patterns are monitored to determine if they are terminable. Once the AR-VS pattern is identified, the then operative post-ventricular atrial refractory period (PVARP) is shortened to allow sensing of the atrial event, which previously was unable to initiate a sensed atrioventricular (SAV) interval. Subsequent SAV intervals are shortened until an atrial event is sensed so that a ventricular pacing stimulus is delivered after the SAV interval expires. Since the SAV interval is normally programmed to an interval that is shorter than the intrinsic conduction time, ventricular pacing stimulus is provided after the SAV ends, thereby effectively restoring delivery of a ventricular pacing modality such as cardiac resynchronization therapy (CTR).

Abstract: An improved pacemaker has a hysteresis feature that activates accelerated pacing during periods of sinus arrest and/or extreme bradycardia. When the patient's intrinsic heart rate drops below a hysteresis rate, the pacemaker reverts to a programmable accelerated rate or to the average cardiac rate. Accelerated pacing is delivered for a programmable period of time, after which the pacing rate is gradually reduced toward a lower rate. If a desirable intrinsic rate is not attained after the pacing rate is reduced to the lower rate, the intervention cycle repeats.

Abstract: A system and method for monitoring left ventricular cardiac contractility and for optimizing a cardiac therapy based on left ventricular lateral wall acceleration (LVA) are provided. The system includes an implantable or external cardiac stimulation device in association with a set of leads including a left ventricular epicardial or coronary sinus lead equipped with an acceleration sensor. The device receives and processes acceleration sensor signals to determine a signal characteristic indicative of LVA during isovolumic contraction. A therapy optimization method evaluates the LVA during varying therapy settings and selects the setting(s) that correspond to a maximum LVA during isovolumic contraction. In one embodiment, the optimal inter-ventricular pacing interval for use in cardiac resynchronization therapy is determined as the interval corresponding to the highest amplitude of the first LVA peak during isovolumic contraction.

Abstract: A battery having an electrode assembly located in a housing that efficiently utilizes the space available in many implantable medical devices is disclosed. The battery housing provides a cover and a shallow case a planar bottom, an open top to receive the cover, and a plurality of sides being radiused at intersections with each other and with the bottom to allow for the close abutting of other components located within the implantable device while also providing for efficient location of the battery within an arcuate edge of the device.

Abstract: Various implantable medical devices (IMDs) are disclosed for implantation in a patient. The IMD includes pacing circuitry configured to selectively produce pacing pulses at a programmable pacing rate. In one embodiment, the IMD is configurable to subject a patient to a stress test. The IMD may be configurable to subject the patient to the stress test at the time specified by stored timing information, or in response to a signal (e.g., from a patient activator). Another embodiment of the implantable medical device (IMD) includes sensor circuitry, a memory for storing data, and a control unit. The sensor circuitry produces sensor data relating to cardiac condition. The control unit is configurable to store the sensor data in the memory until a trigger signal is received. Methods are described for performing a stress test in a patient with an IMD, and for subsequently reproducing cardiac operational states.