Abstract: An apparatus and method is presented for improving cardiac function after successful termination of a tachyarrhythmia such as ventricular fibrillation. A series of electrical stimulation pulses are delivered prior to a defibrillation shock if one or more specific criteria are met.

Abstract: An electrical lead includes an elongate body having a proximal end and a fixation member joined to the elongate body and distally disposed from the proximal end of the elongate body, wherein the fixation member is capable of being extended from and retracted toward the elongate body. A method includes advancing an electrical lead into vasculature and extending a fixation member from the body of the electrical lead to fixedly engage the electrical lead within the vasculature. The method may further include retracting the fixation member toward the body of the electrical lead to unengage the electrical lead within the vasculature and retracting the electrical lead from the vasculature.

Abstract: A method and device for endocrine and exocrine gland control. The method comprises selecting neuro-electrical coded signals from a storage area that are representative of body organ function. The selected neuro-electrical coded signals are then transmitted to a treatment member, which is in direct contact with the body, and which then broadcasts the neuro-electrical coded signals to a specific endocrine and exocrine gland nerve or gland to modulate the gland functioning. A control module is provided for transmission to the treatment member. The control module contains the neuro-electrical coded signals which are selected and transmitted to the treatment member, and computer storage can be provided for greater storage capacity and manipulation of the neuro-electrical coded signals.

Abstract: A self-sufficient retinal prosthesis powered by intra-ocular photovoltaic cells illuminated only by ambient light is provided. Photovoltaic cells can be disposed at the periphery of the retina or in the anterior chamber of the eye. An adaptive retinal prosthesis is also provided, such that the number of pixels energized in the prosthesis is selected according to the variable available power from ambient light.

Abstract: T-wave amplitude and QT interval are derived from patient cardiac signals. Then blood glucose levels are determined based on a combination of the T-wave amplitude and the QT interval. By using a combination of both T-wave-based and QT interval-based signals, blood glucose levels can be reliably detected throughout a wide range of blood glucose levels. Once the blood glucose level has been detected, the implanted device compares the blood glucose level against upper and lower acceptable bounds and appropriate warning signals are generated if the level falls outside the bounds. In one example, wherein an implantable insulin pump is additionally provided, the pump is controlled based on the detected blood glucose level to maintain glucose levels within an acceptable range. A calibration technique is also provided for determining patient-specific parameters for use in the detection of blood glucose levels.

Abstract: Various techniques are described for preventing pacemaker mediated tachycardia (PMT) within biventricular pacing systems and for detecting and terminating PMT should it nevertheless arise. In a first prevention technique, refractory periods applied to the atrial channel are synchronized to begin with a second of a pair of ventricular pacing pulses to more effectively prevent T-wave oversensing on the atrial channel. In a second prevention technique, the sensitivity of the atrial channel is reduced during T-waves also to prevent T-wave oversensing. In a third prevention technique, template matching is performed on the ventricular channels to prevent T-wave oversensing. In a fourth prevention technique, T-wave detection windows are applied to both the ventricular and atrial channels subsequent to any paced or sensed events. In a first detection technique, PMT is detected based upon a degree of variation within V-pulse to P-wave pacing intervals.

Abstract: An implantable cardiac stimulation device provides a stimulation therapy or an atrial ablation recommendation responsive to detection of atrial flutter of a heart. The device includes a sensing circuit that senses electrical activity of a heart and generates electrical signals representing electrical activity of the heart, an arrhythmia detector that detects atrial flutter of the heart, and a data processor that measures cardiac data responsive to the electrical signals. A therapy control responsive to the detection of atrial flutter recommends atrial ablation of the heart when the cardiac data satisfies a predetermined criteria and atrial flutter suppression when the cardiac data fails to satisfy the predetermined criteria. The device may further include a pulse generator that provides stimulation therapy to at least one atrium to terminate the atrial flutter.

Abstract: A device and method for cardiac rhythm management in which one heart chamber, designated as the synchronized chamber, is paced in accordance with a pacing mode that employs sense signals from the opposite chamber, designated as the rate chamber. A synchronized chamber protection period triggered by an intrinsic or paced beat in the synchronized chamber is used to inhibit pacing without otherwise disturbing the pacing algorithm.

Abstract: A defribrillator comprises first and second electrodes (A, B) for application to a patient, a voltage source (60), and an output circuit for connecting the voltage source across the electrodes upon the occurrence of a control signal (64). The output circuit includes a first current path connecting one side of the voltage source to the first electrode (A) and a second current path connecting the other side of the voltage source to the second electrode (B). Each of the current paths contains at least one solid state switching device USD1 (bo) or IGBT1. The switching device(s) USD1 (bo) in at least one of the current paths has no external control and characteristics similar to a Shockley diode.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. The emulation is performed using a matrix-based technique that separately emulates each of the individual signals of a multiple-lead EKG, rather than merely emulating a single combined EKG. In one example, each of the twelve signals of a standard 12-lead EKG are individually emulated, allowing for separate processing and display. The emulation technique takes into account factors affecting the relative locations of the internal leads, such as respiration and posture, to thereby provide a more accurate emulation. A calibration technique is provided for calibrating the EKG emulation for use with a particular patient and a verification technique is provided for automatically verifying the reliability of the emulation. Any significant loss in emulation reliability is likely caused by lead dislodgment and so automatic detection of possible lead dislodgment is also achieved.

Abstract: A system and method for use in an implantable cardiac stimulation device permits automatic induction of a tachyarrhythmia of a heart to permit the performance of an electrophysiological test of the heart. A pulse generator repeatedly delivers a group of first and second sets of pacing pulses to a chamber of the heart. The pacing pulses are separated in time by interpulse intervals to overdrive pace a chamber of the heart. A processor, coupled to the pulse generator, varies the second set of interpulse intervals according to a predetermined protocol after each group of pacing pulses is delivered to the chamber of the heart. The successive groups of pacing pulses are delivered to the heart until the tachyarrhythmia is induced.