Williamson I R, Kitchin A H
Thorax. 1980 Jan;35(1):52-5. doi: 10.1136/thx.35.1.52.
Accurate measurement of pressure differences across a diseased heart valve involves either laborious planimetry or elaborate digital computing facilities. An analogue device is described, simple and inexpensive to construct, which derives from the recorder input of two pressure signals the time (seconds/minute) of valve opening and the mean pressure difference during this time. Measurements may be repeated over long periods. The importance of using pressure differences as compared with peak or end diastolic gradients is noted; serious errors in assessment of valvular disease may otherwise occur.
精确测量病变心脏瓣膜两端的压力差，要么需要费力地进行面积测量，要么需要借助精密复杂的数字计算设备。本文介绍了一种模拟装置，其制作简单且成本低廉，它能从两个压力信号的记录器输入中得出瓣膜开启时间（秒/分钟）以及此期间的平均压力差。测量可在较长时间段内重复进行。文中指出了使用压力差而非峰值或舒张末期梯度的重要性；否则在评估瓣膜疾病时可能会出现严重误差。
