| 摘要 |
An electronic test instrument for measuring the refractory interval of a demand-type cardiac pacer pulse generator. The normal pulse-to-pulse interval of the pacer under test is measured by accumulating regularly occurring timing signals in a first counter during the interpulse period. At a predetermined time after the occurrence of the first pulse defining the interval, a pseudo R-wave is generated and applied to the pacer under test. The next pulse-to-pulse interval is then measured in a second counter in a fashion similar to the first measurement and a test is made to determine if the second interval exceeds the first by a prescribed amount. If so, it is known that the pseudo R-wave was effective to reset the pacer's pulse generator. If not, the time of occurrence of the next pseudo R-wave is delayed by a further known amount and the operation is repeated over and over until an extension of the normal pulse-to-pulse interval is noted. When a point is reached where the pseudo R-wave is displaced in time from a first pacer pulse just enough to cause resetting of the pacer's pulse generator, a measure is made of the displacement interval and this value is visually displayed.
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