目的　探讨基础阻抗（Ｚ０） 对心导纳微分图（ｄｙ／ｄｔ） 与心阻抗微分图（ｄｚ／ｄｔ） 两种方法测量快速射血指数（ＲＥＩ）的影响。方法　观察实验犬胸部不同Ｚ０ 时心导纳微分图最大射血速率（ｄｙ／ｄｔㄧｍａｘ） 及其快速射血指数（ＲＥＩｙ） 与心阻抗微分图最大射血速率（ｄｚ／ｄｔㄧｍａｘ） 及其快速射血指数（ＲＥＩｚ） 的变化，并对照分析。结果　ｄｙ／ｄｔㄧｍａｘ 及ＲＥＩｙ 不受Ｚ０ 改变的影响，而ｄｚ／ｄｔㄧｍａｘ 及ＲＥＩｚ 则随Ｚ０ 增大（ 减小） 而增大（ 减小） 。结论　在无创性心功能检测方法中，ｄｙ／ｄｔ 似较ｄｚ／ｄｔ 更为合理。ＲＥＩｙ 不象ＲＥＩｚ 那样受Ｚ０ 的严重影响，它是一项能较客观地反映心脏收缩强度的理想参数 Objective To investigate the effects of basic impedance (Z0) on rapid ejection index (REI) measurement by two methods, cardiac admittance differential graph (dy / dt) and cardiac impedance differential graph (dz / dt). Methods The maximal ejection rate (dy / dt ㄧ max) and its fast ejection index (REIy) and the maximum ejection rate (dz / dt ㄧ max) The rapid ejection index (REIz) changes, and control analysis. As a result dy / dt ㄧ max and REIy are unaffected by Z0 changes, while dz / dt ㄧ max and REIz increase (decrease) as Z0 increases (decreases). Conclusion In noninvasive cardiac function test, dy / dt seems to be more reasonable than dz / dt. REIy is not as seriously affected by the Z0 as REIz, it is an ideal parameter to more objectively reflect the contraction strength of the heart