Abstract: An implantable cardiac stimulation device classifies ventricular tachyarrhythmias as either a ventricular tachycardia or ventricular fibrillation and applies appropriate therapy. The device include sensing circuits that provide right and left ventricular electrogram signals, a detector that detects an accelerated ventricular arrhythmia, and a classifying circuit that measures relative correspondence between the right and left ventricular electrogram signals to classify a detected accelerated ventricular arrhythmia as either ventricular tachycardia or ventricular fibrillation. A therapy circuit is responsive to the classifying circuit and applies appropriate therapy to the heart based upon the tachyarrhythmia classification.

Abstract: An implantable cardiac stimulation device provides accelerated delivery of defibrillation therapy to a patient's heart. The device includes a sensing circuit that provides right and left heart cardiac activity signals and a detector that detects an accelerated arrhythmia of the patient's heart and establishes a plurality of accelerated cardiac rate zones including a fibrillation rate zone and at least one intermediate rate zone. A classifier responsive to the right and left heart cardiac activity signals classifies an accelerated arrhythmia as one of fibrillation and tachycardia responsive to the detector detecting an accelerated arrhythmia having a cardiac rate within the at least one intermediate rate zones. A therapy circuit applies defibrillation to the heart responsive to the classifier classifying an accelerated arrhythmia as fibrillation and anti-tachycardia pacing to the heart responsive to the classifier classifying an accelerated arrhythmia as tachycardia.

Abstract: An exemplary system and/or method allows for automated and/or semi-automated treatment of CHF, for example, via a pathway. Various exemplary systems and/or methods include a server and/or a client for creating, implementing and/or maintaining a CHF pathway. An exemplary client has a communication link with an implantable cardiac device for communicating one or more operational parameters to the implantable cardiac device and/or receiving information from the implantable cardiac device. Other exemplary systems and/or methods are also disclosed.

Abstract: An implantable cardiac stimulation device discriminates and treats accelerated atrial arrhythmias of a patient's heart. The device includes a sensing circuit that senses cardiac activity of one of the patient's atria to provide an atrial activity signal, a detector that detects an accelerated atrial arrhythmia of the patient's heart, and a classifying circuit that measures relative correspondence between successive P waves of the atrial activity signal to classify the detected accelerated atrial arrhythmia as either atrial tachycardia or atrial fibrillation. A therapy circuit provides anti-tachycardia pacing therapy responsive to a classified atrial tachycardia and defibrillation therapy responsive to a classified atrial fibrillation.

Abstract: Methods and apparatuses are provided for assisting with the diagnosis, monitoring, and/or treatment of patients that are suffering from asymptomatic heart failure or may be susceptible to asymptomatic heart failure. The methods and apparatuses can be implemented with implantable devices. In certain implementations, a method is provided which includes sensing muscle sympathetic nerve activity using at least one nerve sensing electrode that is in electrical contact with a patient's efferent muscle-nerve structure, acquiring a muscle sympathetic nerve activity signal from the sensed nerve activity using a nerve activity sensing circuit operatively coupled to the nerve sensing electrode, and analyzing the nerve activity signal for changes in nerve burst activity indicative of the presence and/or severity of asymptomatic heart failure.

Abstract: An exemplary method includes determining, in vivo, position, displacement and/or spatial time derivatives of myocardial tissue. Such determinations are optionally made with respect to systolic and/or diastolic cycles. Further, position, displacement and/or spatial time derivatives may be used in cardiac diagnosis or therapy. Other exemplary methods, devices and/or systems are also disclosed.

Abstract: An implantable cardiac stimulating device employs an automatic defibrillation threshold tracking process that uses a measured pacing stimulation threshold to estimate the patient's defibrillation threshold on a dynamic, ongoing basis, using changes in the defibrillation threshold to re-calculate new defibrillation parameters (e.g., energy settings) on a periodic basis as a patient's heart changes over time. The defibrillation threshold estimation formula may involve a variety of variables, such as, for example, the patient's age and/or gender, and may include a selected safety margin. New defibrillation parameters are loaded into the appropriate locations of the device's memory, replacing the prior parameters, and are thereafter available for use by the device for defibrillation therapy. The defibrillation threshold tracking technique may be used in an external device, such as a programmer or external cardiac stimulation device.

Abstract: An apparatus and method for determining an optimal transchest external defibrillation waveform that provides for variable energy in the first or second phase of a biphasic waveform that, when applied through a plurality of electrodes positioned on a patient's torso, will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: An apparatus for releasably connecting a wireline to a downhole tool comprises a connector having a first member adapted for connection to the downhole tool and a second member adapted for connection to the wireline. A plurality of locking elements are constrained to engage the first and second members by a moveable release member, where the plurality of locking elements maintain the first and second members in a connected position when the moveable release member is in a first locked position. An electromechanical actuator moves the moveable release member to a second released position, releasing the plurality of locking elements from engagement with the first and second members. This allows the first and second members to release the wireline from the tool.

Abstract: A method and apparatus that pretreat a patient prior to each therapeutic painful stimulus in a series of therapeutic painful stimuli, comprising the application of pain inhibiting stimuli to the patient prior to the application of each therapeutic painful stimulus in the series. Applying pain inhibiting stimuli comprises the steps of sensing a need for a next therapeutic painful stimulus in a series, preparing to deliver the pain inhibiting stimuli to the patient prior to applying the next therapeutic painful stimulus, and delivering the pain inhibiting stimuli to the patient prior to applying the next therapeutic painful stimulus. The method and apparatus are embodied in modern, noninvasive, transcutaneous or transesophageal pacing devices, either as stand-alone cardiac pacemakers, combination pacemaker-ECG monitors, or combination pacemaker-monitor-defibrillators. The pain inhibiting prepulse method is intended primarily for use in conscious patients but may also be used in sleeping patients.

Abstract: A device to monitor and quantify the tension and compression forces acting on a well logging instrument string during deployment. The device eliminates the undesirable effects of downhole hydrostatic pressure on the sensors, and eliminates the need for a costly, complex, and high maintenance hydraulic pressure equalizing system in the force gage assembly. The device provides improved measurement accuracy, provides enhanced reliability and longer life of the sensors, and allows lower cost of manufacture and maintenance.

Abstract: The characteristics of a full-tilt exponential waveform are developed through use of a charge burping model or through use of a transthoracic cell response model. These characteristics are implemented within a pulse delivery circuit, which itself is implemented within an internal defibrillator or within an external defibrillator. The pulse delivery circuit includes at least one switch which starts and stops the delivery of the defibrillation pulse. Delivery of the defibrillation pulse is started by the switch when there is sufficient stored energy to deliver a desired pulse. Delivery of the defibrillation pulse is stopped by the switch when the current flowing through the switch is substantially zero and the exponential waveform of the pulse is substantially fully decayed.

Abstract: A universal joint between adjacent, electrically connected instrument housings for downhole well operations allow the connected housings to bend longitudinally as required to traverse an arced section of a well bore but does not permit relative elongation or twisting about the longitudinal axis of the housings. In one embodiment, a fluid impermeable open passage space at atmospheric pressure surrounds electrical signal carriers linking the instrument circuitry within the two housings. The passage is constructed as a high-pressure flexible bellows or as a braided or spiral wound high-pressure fluid hose. In another embodiment, a fluid impermeable sheath surrounds the signal carriers and encapsulates the signal carriers by a resilient solid. The articulation structure comprises a Cardan-type of universal joint wherein two fingers project longitudinally from the end of each of the housings.

Abstract: An apparatus and method for determining an optimal transchest external defibrillation waveform that provides for variable energy in the first or second phase of a biphasic waveform that, when applied through a plurality of electrodes positioned on a patient's torso, will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: A universal joint between adjacent, electrically connected instrument housings for downhole well operations allow the connected housings to bend longitudinally as required to traverse an arced section of a well bore but does not permit relative elongation or twisting about the longitudinal axis of the housings. I one embodiment, a fluid impermeable open passage space at atmospheric pressure surrounds electrical signal carriers linking the instrument circuitry within the two housings. The passage is constructed as a high-pressure flexible bellows or as a braided or spiral wound high-pressure fluid hose. In another embodiment, a fluid impermeable sheath surrounds the signal carriers and encapsulates the signal carriers by a resilient solid. The articulation structure comprises a Cardan-type of universal joint wherein two fingers project longitudinally from the end of each of the housings.

Abstract: A device to monitor and quantify the tension and compression forces acting on a well logging instrument string during deployment. The device eliminates the undesirable effects of downhole hydrostatic pressure on the sensors, and eliminates the need for a costly, complex, and high maintenance hydraulic pressure equalizing system in the force gage assembly. The device provides improved measurement accuracy, provides enhanced reliability and longer life of the sensors, and allows lower cost of manufacture and maintenance.

Abstract: A device to monitor and quantify the tension and compression forces acting on a well logging instrument string during deployment. The device eliminates the undesirable effects of downhole hydrostatic pressure on the sensors, and eliminates the need for a costly, complex, and high maintenance hydraulic pressure equalizing system in the force gage assembly. The device provides improved measurement accuracy, provides enhanced reliability and longer life of the sensors, and allows lower cost of manufacture and maintenance.

Abstract: A method and apparatus for pretreating a patient prior to a therapeutic painful stimulus, comprising the application of pain inhibiting stimuli to a patient prior to an application of the therapeutic painful stimulus. Applying pain inhibiting stimuli comprises the steps of sensing a need for the therapeutic painful stimulus, preparing to deliver the pain inhibiting stimuli to the patient prior to applying the therapeutic painful stimulus, and delivering the pain inhibiting stimuli to the patient prior to applying the therapeutic painful stimulus. The method and apparatus are embodied in modern, fully automatic, fully implantable, single or dual chamber atrial or ventricular cardioverter-defibrillators. The pain inhibiting prepulse method is intended primarily for use in conscious patients but may also be used in sleeping patients.

Abstract: A device to monitor and quantify the tension and compression forces acting on a well logging instrument string during deployment. The device eliminates the undesirable effects of downhole hydrostatic pressure on the sensors, and eliminates the need for a costly, complex, and high maintenance hydraulic pressure equalizing system in the force gage assembly. The device provides improved measurement accuracy, provides enhanced reliability and longer life of the sensors, and allows lower cost of manufacture and maintenance.

Abstract: An apparatus and method for determining an optimal transchest external defibrillation waveform that provides for variable energy in the first or second phase of a biphasic waveform that, when applied through a plurality of electrodes positioned on a patient's torso, will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.