초록 ▼

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 up

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.

대표청구항 ▼

[ What is claimed is:] [1.] A cardiac pulse delivery and sensing apparatus comprising:a housing adapted to be implanted in an individual said housing containing means for generating and delivering stimulating pulses to an electrical connection outside said housing said electrical connection arranged

[ What is claimed is:] [1.] A cardiac pulse delivery and sensing apparatus comprising:a housing adapted to be implanted in an individual said housing containing means for generating and delivering stimulating pulses to an electrical connection outside said housing said electrical connection arranged and disposed for electrical connection to sensing and stimulating pulse delivery lead means and wherein said lead mean are configured and designed to allow for implantation so as to be in close association with said individual's heart so as to provide electrical connection between said heart and said electrical connection,a timing and control processor circuit and a memory circuit within said housing having control of the timing of delivery of said stimulating pulses and for timing said sensed heart signals and for storing values related to such timing in an associated portion of said memory circuit and wherein said processor circuit comprises as least two processors; a rate smoothing determining processor for determining whether rate smoothing criteria are met in sensed signals from said heart when a rapid rate drop is detected and; a rate support determining processor for determining from said values related to such timing when to maintain a support rate, said maintenance of support rate processor having two modes, a tracking mode which follows an intrinsic atrial rate and a decay mode which allows the support rate to fall in a controlled manner and wherein said timing and control processor circuit also comprises circuit means for adjusting the timing of said stimulating pulses in response to said rate smoothing processor and rate support processor's determining.