Abstract: Systems and methods for analyzing electronic cardiac signals for use in clinical diagnostics are described. Parameters pertinent to a first cardiac condition of a patient, such as determining an orientation of a vector related to the cardiac activity of said patient, and comparing the vector orientation relative to a centerpoint of a population distribution representative of a second cardiac condition, may be utilized. The second cardiac condition may be selected from the group consisting of benign early repolarization, left ventricular hypertrophy, and right bundle branch block. System and method embodiments are configured to assist in the analysis of details of EKG signals and vector cardiograms to determine how patients should be categorized into specific cardiac risk categories, such as an acute coronary syndrome category.

Abstract: Systems and methods for analyzing electronic cardiac signals for use in clinical diagnostics are described. System and method embodiments are configured to assist in the analysis of details of EKG signals and vector cardiograms to determine how patients should be categorized into specific cardiac risk categories, such as an acute coronary syndrome category. System configurations may comprise memory devices, computing systems, and EKG data sources positioned at various local or remote positions, and connected via various data connectivity modalities. Various parameters may be utilized to assist in the drawing of one or more conclusions regarding the cardiac condition of a patient.

Abstract: A system includes a mobile unit having a plurality of electrodes, numbering less than ten, that are configured to contact a patient to obtain electrical signals therefrom, and a diagnostic center disposed remotely from the mobile unit. The mobile unit and/or the diagnostic center are configured to construct a first portion of an ECG (electrocardiogram) corresponding to a first portion of a cardiac cycle of the patient by processing information based on received electrical signals using a first set of transformation parameters corresponding to the first portion of the cardiac cycle. The first portion may correspond to atrial or ventricular activity.

Abstract: An implantable system acquires intracardiac impedance with an implantable lead system. In one implementation, the system generates frequency-rich, low energy, multi-phasic waveforms that provide a net-zero charge and a net-zero voltage. When applied to bodily tissues, current pulses or voltage pulses having the multi-phasic waveform provide increased specificity and sensitivity in probing tissue. The effects of the applied pulses are sensed as a corresponding waveform. The waveforms of the applied and sensed pulses can be integrated to obtain corresponding area values that represent the current and voltage across a spectrum of frequencies. These areas can be compared to obtain a reliable impedance value for the tissue. Frequency response, phase delay, and response to modulated pulse width can also be measured to determine a relative capacitance of the tissue, indicative of infarcted tissue, blood to tissue ratio, degree of edema, and other physiological parameters.

Abstract: A system for monitoring a cardiac condition of a patient includes a diagnostic center configured to construct a 12-lead ECG of a patient using a special ECG signals numbering less than twelve by combining the special ECG signals with a transformation matrix, and a wearable device configured to generate the special ECG signals and including. The wearable device includes a belt having one or more belt electrodes, a waistband having one or more waistband electrodes, the belt and waistband electrodes configured to contact the skin of the patient and obtain electrical signals therefrom, and a host unit in electrical communication with the belt and waistband electrodes, the host unit including circuitry for generating the special ECG signals from one or more of the acquired electrical signals and circuitry for special ECG signals to a location remote from the wearable device.

Abstract: Techniques are provided for estimating left atrial pressure (LAP) or other cardiac pressure parameters based on various parameters derived from impedance signals. In particular, effective LAP is estimated based on one or more of: electrical conductance values, cardiogenic pulse amplitudes, circadian rhythm pulse amplitudes, or signal morphology fractionation values, each derived from the impedance signals detected by the implantable device. Predetermined conversion factors stored within the device are used to convert the various parameters derived from the electrical impedance signal into LAP values or other appropriate cardiac pressure values. 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.

Abstract: An apparatus and method for catheter-based sensing and injection at a target site within a patient's body. An injection catheter is equipped with electrodes at its distal end which contact the surface of a target site, such as an AV node of the heart. Electrical signals detected at the target site by the electrodes are fed via leads to the proximal end of the catheter, where they are received by a monitor, such as an EKG monitor. If the electrical signals satisfy predetermined criteria, a needle within the catheter is extended into the target site, and a therapeutic agent is injected into the target site.

Abstract: Techniques are provided for detecting and evaluating ventricular dyssynchrony based on morphological features of the T-wave and for controlling therapy in response thereto. For example, the number of peaks in the T-wave, the area under the peaks, the number of points of inflection, and the slope of the T-wave can be used to detect ventricular dyssynchrony and evaluate its severity. As ventricular dyssynchrony often arises due to heart failure, the degree of dyssynchrony may also be used as a proxy for tracking the progression of heart failure. Pacing therapy is automatically and adaptively adjusted based on the degree of ventricular dyssynchrony so as to reduce the dyssynchrony and thereby improve cardiac function.

Abstract: In one embodiment an implantable cardiac device is provided that includes an implantable cardiac stimulation device with an implantable satellite device coupled to it. The implantable satellite device has a charge storage device. The implantable stimulation device having a refresh generator configured to generate a charge and voltage balanced multi-phasic refresh signal with a duration less than a capacitive time constant of an electro-electrolyte interface of the implantable cardiac device and transmit the charge and voltage balanced multi-phasic refresh signal to the implantable satellite device for charging the charge storage device. In various embodiments, the charge and voltage balanced multi-phasic refresh signal having alternating phase signs and null durations between the alternating phases. In some embodiments, the refresh generator is configured to modulate the multi-phasic waveform refresh signal.

Abstract: A wireless communication threshold for an implantable medical device is automatically adapted in an attempt to maintain optimum signal detection sensitivity. In some aspects, a threshold level may be adapted to account for current environmental conditions, implant conditions, device conditions, or other conditions that may affect the reception of wireless signals at the device. In some aspects, the determination of an optimum level for the threshold involves a tradeoff relating to effectively detecting target signals while avoiding detection of noise and/or interference. In some aspects, adaptation of a threshold may be based on maximum energy levels associated with one or more sets of RF energy sample data. In some aspects, adaptation of a threshold may be based on the number of false wakeups that occur during a period of time.

Abstract: Techniques are provided for detecting heart failure or other medical conditions within a patient using an implantable medical device, such as pacemaker or implantable cardioverter/defibrillator, or external system. In one example, physiological signals, such as immittance-based signals, are sensed within the patient along a plurality of different vectors, and the amount of independent informational content among the physiological signals of the different vectors is determined. Heart failure is then detected by the implantable device based on a significant increase in the amount of independent informational content among the physiological signals. In response, therapy may be controlled, diagnostic information stored, and/or warning signals generated. In other examples, at least some of these functions are performed by an external system.

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: 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.

Abstract: Systems and methods for controlling the power supplied to an electrosurgical probe. The systems and methods may be used to monitor electrode-tissue contact, adjust power in response to a loss of contact, and apply power in such a manner that charring, coagulum formation and tissue popping are less likely to occur.

Abstract: An apparatus and method for catheter-based sensing and injection at a target site within a patient's body. An injection catheter is equipped with electrodes at its distal end which contact the surface of a target site, such as an AV node of the heart. Electrical signals detected at the target site by the electrodes are fed via leads to the proximal end of the catheter, where they are received by a monitor, such as an EKG monitor. If the electrical signals satisfy predetermined criteria, a needle within the catheter is extended into the target site, and a therapeutic agent is injected into the target site.

Abstract: 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.

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: The present invention provides multi-functional medical catheters, systems and methods for their use. In one particular embodiment, a medical catheter (100) includes a flexible elongate body (105) having a proximal end (110) and a distal end (120). A plurality of spaced apart electrodes (130-136) are operably attached to the flexible body near the distal end. At least some of the electrodes are adapted for mapping a tissue and, in some embodiments, at least one of the electrodes is adapted for ablating a desired portion of the tissue. The catheter includes a plurality of tissue orientation detectors (140-146) disposed between at least some of the electrodes. In this manner, the medical catheter is capable of tissue mapping, tissue imaging, tissue orientation, and/or tissue treatment functions.

Abstract: The present invention provides multi-functional medical catheters, systems and methods for their use. In one particular embodiment, a medical catheter (100) includes a flexible elongate body (105) having a proximal end (110) and a distal end (120). A plurality of spaced apart electrodes (130-136) are operably attached to the flexible body near the distal end. At least some of the electrodes are adapted for mapping a tissue and, in some embodiments, at least one of the electrodes is adapted for ablating a desired portion of the tissue. The catheter includes a plurality of tissue orientation detectors (140-146) disposed between at least some of the electrodes. In this manner, the medical catheter is capable of tissue mapping, tissue imaging, tissue orientation, and/or tissue treatment functions.

Abstract: A system for denaturing corneal tissue. The system includes a ground element and an electrode coupled to a power unit. The electrode is inserted into a cornea. The power unit provides power to the electrode to denature corneal tissue. The power may be at a level so that the temperature of the corneal tissue adjacent to the electrode is such that it minimizes tissue overheating. The power may be applied for a time duration up to 30 seconds at a level that does not exceed 500 mW. The surgeon may dial in an input parameter that correlates with a diopter correction in a cornea.