| 摘要 |
<p>A physiological sensor for use with a pacemaker (16) is disclosed. The sensor allows the rate at which the pacemaker delivers electrical stimulation pulses to the heart (18), or the escape interval during which a natural heart event must occur before an electrical stimulation pulse is delivered, to be adjusted as needed in order to satisfy the body's physiological needs. The sensor utilizes the measured time interval between an atrial stimulation pulse, A, and the responsive atrial or ventricle depolarization as determined by an interval measurement circuit (71), as a measure or indication of the physiological demands placed on the heart. The time interval between a ventricular stimulation pulse, V, and the responsive ventricular depolarization may also be used as a measure of physiological need, and hence as an alternative criteria for rate control. Atrial depolarization is sensed by detecting a P-wave, and ventricular depolarization is preferably sensed by detecting an R-wave. P-wave and R-wave sense amplifiers (48, 54, 56), connected to an atrial pacing/sense lead (22) and a ventricular pacing/sense lead (30), are used to perform this sensing function. The A-P, A-R, or V-R intervals thus measured are processed in a physiological detector (73) in order to ascertain if these intervals are increasing or decreasing. If, over several heart cycles or beats, an increase or decrease in these measurements is detected, the pacing interval set by the pacemaker's pulse generator logic (42) is adjusted in an appropriate direction in order to adjust the heart beat rate accordingly.</p> |
