摘要:
An apparatus and method for displaying and controlling parameters for a programmable living tissue stimulator system. Visual indicators corresponding to control parameters or signals for the tissue stimulator system are divided into a predetermined number of groups. One of these groups containing a parameter to be selected for the tissue stimulator system is selected, the selected group being identified by a visually identifiable indication. A parameter within that group is then selected for transmission to an implanted memory means which controls an implanted tissue stimulator. In a specific embodiment, a matrix of visual indicators consisting of R rows and S columns is provided, each visual indicator corresponding to a specific control signal. A means is provided whereby at least one visual indicator contained in a selected R row will blink on and off, the blinking indicators identifying control signals to be selected for the implanted memory means. Selection of a control signal within the selected R row causes the blinking to cease and the visual indicator corresponding to the selected signal to turn on when the selected signal is stored within the implanted memory means. Visual indicators corresponding to the unselected control signals in the selected R row turn off after a signal selection is made.
摘要:
Techniques are provided for detecting a clinically-significant pulmonary fluid accumulation within a patient using a pacemaker or other implantable medical device. Briefly, the device detects left atrial pressure (LAP) within the patient and tracks changes in the LAP values over time that are indicative of possible pulmonary fluid accumulation within the patient. The device determines whether the changes in LAP values are sufficiently elevated and prolonged to warrant clinical intervention using, e.g., a predictor model-based technique. If the fluid accumulation is clinically significant, the device then generates warning signals, records diagnostics, controls therapy and/or titrates diuretics. False positive detections of pulmonary edema due to transients in LAP are avoided with this technique. Pulmonary artery pressure (PAP)-based techniques are also described.
摘要:
A single-pass A-V lead for cardiac pacing comprises a lead body having an atrial electrode and a right ventricular outflow tract (RVOT) electrode. Preformed bends in the lead body are configured such that the atrial and RVOT electrodes are biased against walls of the right atrium and the RVOT respectively. Biasing forces generated by the preformed bends help to maintain the atrial and RVOT electrodes in their respective positions following implantation. The lead advantageously permits ventricular stimulation in the RVOT, resulting in an improved sequence of ventricular activation and a corresponding increase in cardiac output. Branched and unbranched embodiments of the lead are disclosed.
摘要:
Atrial lock interval pacing increases stroke volume and optimizes cardiac output by providing a modified P-wave tracking mode that tracks P-waves up to a maximum instantaneous tracking rate only for short periods of time, to provide a maximum instantaneous ventricular heart rate, yet limits the maximal mean (or average) ventricular rate over a longer period of time, to provide a safe target maximal average rate. Two main types or embodiments of modified P-wave tracking modes may be used. A first provides a sequence of timed intervals that begins upon sensing each P-wave. Such sequence may include, e.g.: (1) a PV interval; (2) a PVARP; (3) a Wenkebach interval; (4) an atrial lock interval; and (4) a P-track interval. P-waves are not tracked during the PV interval or PVARP. P-waves that occur during the Wenkebach or Atrial lock interval are tracked, but not in a conventional manner. P-waves that occur during the P-track interval are tracked in a conventional manner. A second modified P-wave tracking mode defines a maximum mean rate (MMR) interval. The MMR interval (MMRI) is an asynchronous free-running signal that is not synchronized to any cardiac cycle events. During each MMRI, the number of atrial or ventricular events that occur are noted. Ventricular stimulation pulses (V-pulses) are not generated if the resulting ventricular depolarization would represent the second ventricular depolarization of the current MMRI.
摘要:
A programmable cardiac stimulator capable of stimulation in the DDX modality having a first sensing system (46) for sensing electrical activity in the atrium, a second sensing system (48) for sensing electrical activity in the ventricle, a pulse generator (24) connected to the first (46) and second (48) sensing system and responsive to electrical activity sensed by these systems (46, 48) for determining the timing for supplying electrical pulses to the atrium and ventricle, for this depolarization and a circuit with the pulse generator (24) for changing the stimulation modality from DDD to DVI when premature ventricular activity is sensed by the second sensing system (46) prior to sensing electrical activity by the first sensing system (48) during the pacer cycle.
摘要:
A method for accessing a target site in the body by transferring a guidewire from an initial insertion site on the body to a different insertion site on the body is provided. In one aspect, a method for transferring a medical device or component, such as a sensor lead, from an initial insertion site to another insertion site is also provided. A guidewire of sufficient length, pliancy and deformability to perform a transfer from one insertion site to another insertion site is provided. In one aspect, the guidewire comprises a removable core mandrel to increase rigidity, facilitate insertion and/or improve steerability. A kit or system, comprising introducers, guidewires and catheters for performing a guidewire or device transfer is also provided.
摘要:
This invention relates generally to systems and methods for optimizing the performance and minimizing complications related to implanted sensors, such as pressure sensors, for the purposes of detecting, diagnosing and treating cardiovascular disease in a medical patient. Systems and methods for anchoring implanted sensors to various body structures is also provided.
摘要:
A pacemaker programmer and diagnostic system retrieves information stored within a pacemaker and analyzes the retrieved data in real time. The stored information can be retrieved by means of a telemetry communication link. The pacemaker automatically lengthens a post-ventricular atrial refractory period (PVARP). The pacemaker determines atrial capture threshold by generating atrial stimulation pulses while maintaining the ventricular stimulation pulse amplitude at a level known to ensure ventricular capture, and by detecting loss of atrial capture. In response to loss of atrial capture, a processor automatically triggers a premature ventricular contraction (PVC) response to prevent a retrograde P-wave from initiating a pacemaker-mediated tachycardia. Also in response to loss of atrial capture, the processor sets the atrial stimulation pulse amplitude to a value above the atrial capture threshold in a subsequent cardiac cycle, and restores the PVARP to its pre-test value.
摘要:
Methods and apparatus are provided for alleviating the effects of crosstalk in an implantable stimulation device. An autoblanking approach is provided whereby the total blanking interval is made up of an absolute blanking interval followed by a retriggerable relative blanking interval. The implantable stimulation device sensing circuitry is disabled during the absolute blanking interval and enabled during the relative blanking intervals. If a signal is detected during a relative blanking interval, a successive relative blanking interval is initiated. If no signal is detected, then relative blanking terminates. Further, an approach for combining safety standby pacing with autoblanking is provided. If autoblanking terminates before the crosstalk sensing interval reaches a maximum blanking interval, then safety standby pacing is cancelled. Another aspect of the invention relates to monitoring the amount of time in a safety standby sensing window during which signals are detected. If signals are detected longer than a predetermined time, then a safety standby stimulation pulse is provided, otherwise, safety standby pacing is inhibited.
摘要:
This invention relates generally to systems and methods for optimizing the performance and minimizing complications related to implanted sensors, such as pressure sensors, for the purposes of detecting, diagnosing and treating cardiovascular disease in a medical patient. Systems and methods for anchoring implanted sensors to various body structures is also provided.