Abstract: An atrial cardioverter and a method of its operation. The cardioverter measures an interval between successive R-waves, defines a ventricular escape interval as a function of the measured interval between successive R-waves and delivers a ventricular pacing pulse at the expiration of the ventricular escape interval in the absence of R-waves during the ventricular escape interval. The cardioverter defines a synchronization interval following delivery of the ventricular pacing pulse, and delivers an atrial cardioversion pulse synchronized to an R-wave occurring after expiration of the synchronization interval, absent R-waves during the synchronization interval.

Abstract: A method and system facilitates the access by a patient of implanted medical device related data for patient participation in their own clinical care and therapy. In an example embodiment, the method includes establishing a communications link between an implanted medical device and a data processor via an implanted medical device interface. Access to a secured database is obtained via the implanted device data processor using a set of patient identification data. A query is then submitted via the data processor to the secured database in response to input patient diagnostic data. Data received from the secured database is then displayed for use in a patient evaluation.

Abstract: A catheter assembly and method for treatment of cardiac arrhythmia, for example, atrial fibrillation, by electrically isolating a vessel, such as a pulmonary vein, from a chamber, such as the left atrium. The catheter assembly includes a catheter body and at least one electrode. The catheter body includes a proximal portion, an intermediate portion and a distal portion. The intermediate portion extends from the proximal portion and defines a longitudinal axis. The distal portion extends from the intermediate portion and forms a substantially closed loop transverse to the longitudinal axis. The at least one electrode is disposed along the loop. With this configuration, the loop is axially directed into contact with the chamber wall about the vessel ostium. Upon energization, the electrode ablates a continuous lesion pattern about the vessel ostium, thereby electrically isolating the vessel from the chamber.

Abstract: The invention relates to a system and method for the generation of television channels and which allows the generation of the same by the processing and selection of designated packets of data from multiple data transport streams, with each transport stream including numerous packets of data. In each transport stream the packet of data is identified by the allocation of a packet identification Code (PID) and each is held in the transport packet which is transmitted as part of each transport stream. In accordance with the invention, and in order to prevent errors and inaccurate packet selection, a Transport Stream Identification Code (TSID) is allocated to each of the transport streams of data received. Typically the TSID is located in the transport packet for each transport stream of data. In the selection of a packet of data, the appropriate TSID is referred to identify the appropriate transport stream and the PID then referred to identify the packet of data from that transport stream.

Abstract: A catheter assembly and method for treatment of cardiac arrhythmia, for example, atrial fibrillation, by electrically isolating a vessel, such as a pulmonary vein, from a chamber, such as the left atrium. The catheter assembly includes a catheter body and at least one electrode. The catheter body includes a proximal portion, an intermediate portion and a distal portion. The intermediate portion extends from the proximal portion and defines a longitudinal axis. The distal portion extends from the intermediate portion and forms a substantially closed loop transverse to the longitudinal axis. The at least one electrode is disposed along the loop. With this configuration, the loop is axially directed into contact with the chamber wall about the vessel ostium. Upon energization, the electrode ablates a continuous lesion pattern about the vessel ostium, thereby electrically isolating the vessel from the chamber.

Abstract: The invention relates to the provision of a system and control means which allows the storage and subsequent retrieval of data on a storage means such as, for example, a storage means in the form of, and known as, a hard disk drive. Furthermore the invention is related to the storage of data in the form of video, audio and/or auxiliary data which is transmitted from a remote location and received by receiver apparatus for the processing and subsequent generation of video, audio, and/or auxiliary data via a television screen connected to or including the receiver. In some instances the data is not decoded and displayed immediately and the decoding and/or the display of the data, when it does occur may be obtained from the storage means. The control system of the storage means includes a First In First Out (FIFO) buffer which in conjunction with a Central Processing Unit (CPU) controls the generation of the control signals and the storage of the incoming data.

Abstract: An implantable anti-tachyarrhythmia device which delivers atrial cardioversion or defibrillation pulses heart in response to detection of atrial tachyarrhythmias. The pulses are synchronized to atrial and ventricular events in such a fashion as to assure they occur outside of the vulnerable periods associated with both chambers.

Abstract: A method and apparatus for determining the occurrence of a mis-location of an atrial electrode in a cardiac stimulation device having an atrial pulse generator coupled with the atrial electrode and a ventricular sense amplifier coupled to a ventricular electrode. The device paces the atrium in a first pacing mode employing atrial pacing pulses at a first energy level and in a test mode employs higher energy atrial pacing pulses. In the test mode the device measures PR intervals between atrial pacing pulses following sensed ventricular depolarizations and determines that the atrial electrode is mis-located responsive to occurrence of a threshold number of short PR intervals or that the atrial electrode is appropriately located responsive to occurrence of a threshold number of long PR intervals. Operation of the device in the test mode may be pre-conditioned on an absence of atrial tachyarrhythmia.

Abstract: A cardiac pacemaker and a method of its use. The pacemaker paces a patient's heart in a tachyarrhythmia prevention pacing mode for an extended time period, defines a metric of success of the tachyarrhythmia prevention pacing mode, monitors the metric over the extended time period and, responsive to the monitored metric, adjusts the tachyarrhythmia prevention pacing mode. Adjustment of the tachyarrhythmia prevention pacing mode may take the form of pacing the patient's heart with a different set of electrodes, pacing the patient's heart with a different tachyarrhythmia prevention pacing mode and/or terminating operation of the tachyarrhythmia prevention pacing mode.

Abstract: An implantable anti-tachyarrhythmia device which delivers atrial cardioversion or defibrillation pulses heart in response to detection of atrial tachyarrhythmias. The pulses are synchronized to atrial and ventricular events in such a fashion as to assure they occur outside of the vulnerable periods associated with both chambers. The device is provided with a pulse synchronizer which defines a first synchronization interval initiated following a sensed atrial event and a second synchronization interval initiated responsive to a sensed ventricular event and a pulse triggerer which triggers delivery of a cardioversion or defibrillation pulse responsive to the first and second synchronization intervals simultaneously being underway. In particular, the pulse triggerer may be responsive to initiation of the first synchronization interval during the second synchronization interval.

Abstract: An atrial cardioverter and a method of its operation. The cardioverter measures an interval between successive R-waves, defines a ventricular escape interval as a function of the measured interval between successive R-waves and delivers a ventricular pacing pulse at the expiration of the ventricular escape interval in the absence of R-waves during the ventricular escape interval. The cardioverter defines a synchronization interval following delivery of the ventricular pacing pulse, and delivers an atrial cardioversion pulse synchronized to an R-wave occurring after expiration of the synchronization interval, absent R-waves during the synchronization interval.

Abstract: An implantable medical device which senses atrial electrograms, detects atrial tachyarrhythmias and delivers atrial cardioversion/defibrillation pulses in response thereto, which employ a correlation analysis to assist in detection of arrhythmias and/or timing of delivery of cardioversion/defibrillation shocks. The device includes an electrogram recorder which stores atrial electrogram segments associated with R--R intervals extending over multiple atrial depolarizations and a correlator which measures correlation of successive stored atrial electrogram segments. The device may use the measured corellation meeting a defined threshold value to detect the occurrence of a defined tachyarrhythmia such as atrial fibrillation or allow delivery of a cardioversion/defibrillation pulse.

Abstract: An implantable cardioverter for providing cardioversion electrical energy to at least one chamber of a patient's heart in need of cardioversion and applying a pain alleviating therapy at an appropriate site in the patient's body prior to or in conjunction with the delivery of the cardioversion energy to the heart chamber to alleviate propagated pain perceived by the patient. The combined cardioversion and pain alleviating therapies are preferably realized in a single implantable, multiprogrammable medical device or separate implantable cardioversion and pain control devices with means for communicating operating and status commands between the devices through the patient's body.

Abstract: In an implantable pacemaker/cardioverter/defibrillator, a system for correlating the delivery of a cardioversion therapy to an optimum point or phase of the respiratory cycle of the patient to effect delivery of the therapy when the impedance between the cardioversion electrodes is minimized. In a first application for use with cardioversion electrodes located substantially in contact with the heart chamber, the optimum point or phase is at the end of inspiration. In a second application for use with at least one cardioversion electrode located remotely from the heart chamber, the optimum point or phase is at end expiration or beginning of inspiration. The cardioversion therapy is delivered in synchrony with a ventricular sense event, if present. If the optimum point or phase of the respiratory cycle cannot be determined during a therapy time, a pre-shock may be delivered to elicit a respiration cycle through a stimulated contraction of the diaphragm.

Abstract: An implantable cardioverter for providing cardioversion electrical energy to at least one chamber of a patient's heart in need of cardioversion and applying a pain alleviating therapy at an appropriate site in the patient's body prior to or in conjunction with the delivery of the cardioversion energy to the heart chamber to alleviate propagated pain perceived by the patient. The combined cardioversion and pain alleviating therapies are preferably realized in a single implantable, multiprogrammable medical device or separate implantable cardioversion and pain control devices with means for communicating operating and status commands between the devices through the patient's body.

Abstract: A method and apparatus for treating atrial tachyarrhythmias, particularly atrial fibrillation. High energy pulses are delivered between electrodes located in the right atrium/SVC, the left pectoral region and the coronary sinus/great vein, with the left pectoral and coronary sinus/great vein electrodes connected in common. Optionally a ventricular electrode may also be employed in conjunction with one or more of the other listed electrodes to accomplish ventricular cardioversion or defibrillation.

Abstract: A method and apparatus for preventing fibrillation, particularly atrial fibrillation or flutter. In response to detection of an atrial premature beat at any given site in the atrial chamber, a low energy pulse burst is delivered to multiple sites of at least one chamber of the atrium for a time period sufficient to depolarize the entire atrium. Preferably, multiple pairs of sense electrodes are distributed about an atrial chamber or both atria to define discrete sensing sites and to widely distribute the simultaneously applied pacing energy pulse burst. Bradycardia pacing between the multiple electrode pairs is also preferably provided.

Abstract: An implantable cardioverter for providing cardioversion electrical energy to at least one chamber of a patient's heart in need of cardioversion and applying a pain alleviating therapy at an appropriate site in the patient's body prior to or in conjunction with the delivery of the cardioversion energy to the heart chamber to alleviate propagated pain perceived by the patient. The combined cardioversion and pain alleviating therapies are preferably realized in a single implantable, multi-programmable medical device or separate implantable cardioversion and pain control devices with means for communicating operating and status commands between the devices through the patient's body.

Abstract: A method and apparatus for inducing fibrillation in a patient, for example to verify the efficacy of a defibrillator system. In the disclosed embodiment, an implantable cardioverter-defibrillator has an output stage coupled via a plurality of leads to the patient's heart. When it is desired to induce fibrillation in the patient, the device's control circuitry initiates an output capacitor charging cycle and subsequent delivery of a multi-phase fibrillation inducing stimulus to the heart. The multiple phases of the stimulus reflect an incremental discharging of the output capacitor. In one embodiment, the stimulus has three phases, with the first two separated by a time interval equal to or slightly less than the patient's "vulnerability window," which is defined as the time period following a paced cardiac event during which repolarization of the cardiac muscle is occurring, rendering the heart susceptible to induced fibrillation.

Abstract: A method and apparatus for detecting and treating atrial fibrillation. In response to detecting atrial fibrillation, the device derives an escape interval based on one or more preceding intervals between ventricular depolarizations. The escape interval is initiated in response to a ventricular depolarization, and in response to the expiration of the escape interval, an atrial cardioversion pulse is delivered. In one embodiment of the invention, the cardioverting pulse is delivered immediately upon expiration of the derived escape interval. In a second embodiment of the invention, a ventricular pacing pulse is delivered on expiration of the escape interval, with an atrial cardioversion pulse following after a short delay.