摘要:
An AV search method and apparatus is taught with some variation described. It allows a pacemaker to find the appropriate AV interval so as to avoid pacing in the ventricle when it is not necessary, even if there is intermittent AV conduction in the patient. Also, an adaptive PVARP method and apparatus is disclosed that allows the PVARP and AV interval to be adjusted together automatically.
摘要:
A pacemaker control method and apparatus for determining the presence of atrial tachyarrhythmias uses a true interval value and compares it to a predetermined tachy value. The true interval value is updated based on the presence of far field R waves in PVARP that meet certain sequencing criteria. The criteria selected allows the control method and apparatus to reduce or eliminate event sequences that will generate false positive tachy detection and subsequent mode switching, while still allowing for the detection of tachy events in PVARP.
摘要:
A rate-responsive cardiac pacemaker implements a novel pacing mode, identified as ADIR/VVIR, which is especially effective for patients with Sick Sinus Syndrome and only intermittent atrioventricular block. Within the same pacemaker circuitry, an AAIR pacemaker and a VVI pacemaker (with an escape rate below that of the AAIR pacemaker) are provided with atrial blanking following both atrial and ventricular events. Ventricular blanking after atrial pacing is minimized for better detection of R-waves following an atrial paced event.
摘要:
A method and apparatus for variable rate cardiac stimulation, wherein sudden drops in the rate of delivery of stimulation pulses are avoided by means of rate smoothing and peak rate support functions. In one embodiment, circuitry in a cardiac pulse generator detects atrial events and maintains an updated value of the A-A time intervals between certain atrial events. If a preset ratio or total of these A-A intervals are found to have been shorter than the updated value by at a least a predetermined amount of time, a rate smoothing function is activated wherein the rate of delivery of stimulating pulses is prevented from changing, from cycle to cycle, by more than a predetermined maximum amount. A peak rate support function preferably employs the same updated value in the computation of "escape" intervals. Following the latest A-A interval, if that A-A interval is less than the updated value, then the updated value is used as the new escape interval. If the latest A-A interval is greater than or equal to the updated value but less than the previous updated value, the current escape interval is used as the new escape interval. If the latest A-A interval is less than both the previous updated value and the current updated value, the value updated is used as the new escape interval, and the pulse generator enters a decay mode wherein the escape interval is gradually and incrementally lengthened to prevent sudden changes in the rate of delivery of stimulation pulses.
摘要:
A method and apparatus for cardiac pacing, in which pacing pulses are provided at an increased rate in response to a detected rapid drop in heart rate. A rapid drop is detected in response to heart rate falling from a persistent rate above a first threshold rate to a stable rate below a second threshold rate. If spontaneous depolarizations are detected while pacing at the increased rate, pacing at the increased rate is terminated.
摘要:
Some false tachy detection prevention algorithms miss blocked 2:1 sensing and therefore miss some true tachy situations. Here an algorithm that uses sensed far field R waves to determine whether to search for blocked 2:1 sensing is implemented and a search algorithm is also described.
摘要:
A system for accessing implantable medical device (IMD) data is provided including an interrogation appliance to retrieve data from an IMD and transfer the data to a processor. The processor converts the device data to a viewable form that is transferred by the processor to a data destination. The data destination may be an electronic mail address, a secure web site, a facsimile number or the interrogation appliance. The data is presented in a viewable form at the data destination either on a display or by printing. Any number of interrogation appliances may be communicatively coupled to the processor for converting IMD data and providing the IMD data back to a data destination in a viewable form for use by a clinician.
摘要:
A system that includes a programming device and a defibrillator provides a self-adapting defibrillator induction feature to test the effectiveness of the defibrillator in detecting and terminating fibrillation of a heart, such as ventricular fibrillation. A fibrillation induction protocol and values for parameters of the protocol are selected. The defibrillator attempts to induce fibrillation according to the selected protocol and parameter values. Parameter values are modified and new protocols are selected until fibrillation is successfully induced, detected and terminated.
摘要:
An atrial and ventricular pacemaker including an atrial pulse generator having the capability of delivering high rate atrial pacing pulses for electrophysiologic study and having the capability of delivering ventricular pacing pulses as a backup, during delivery of high rate atrial pacing pulses. Delivery of backup ventricular pacing pulses may be preconditioned upon the occurrence of a desired number, proportion or pattern of occurrences of paced ventricular beats preceding delivery of high rate atrial pacing pulses. Timing of ventricular backup pulses is synchronized to delivered atrial pacing pulses which occur closely timed to expiration of a defined ventricular escape interval for backup pacing. The defined escape interval for ventricular backup pacing may be set as a function of the average interval separating ventricular events preceding initiation of high rate atrial pacing.
摘要:
An implantable medical device used for thoracic fluid monitoring by detection of changes in impedance in a patient. The device measures impedances of the patient in a supine position and in an upright position. The device determines impedance differences between the supine and upright positions which correspond to a diurnal delta value, which may in turn be employed as a diagnostic parameter.