Clavin O E, Spinelli J C, Alonso H, Solarz P, Valentinuzzi M E, Pichel R H
Med Prog Technol. 1986;11(1):17-24.
Left ventricular function can be assessed with pressure-volume diagrams (DPV). Since there exists a relationship between ventricular volume changes and changes in intraventricular impedance (ZIV), we propose a diagram, DPZ, obtained from the intraventricular pressure (PIV) and the ZIV signals. This method was tested in 10 anesthetized mongrel dogs (morphine, sc, 30 mg/kg, and pentobarbital, sc, 5-7 mg/kg). PIV was measured with a Millar microtip catheter advanced under fluoroscopy via the femoral artery. ZIV was measured with a laboratory impedance meter (100 microA rms constant current, 12 kHz) in a tetrapolar configuration using another intraventricular catheter. ECG, aortic pressure and basal ZIV were also recorded to help identification of the different cardiac cycle phases on the diagram. Single-beat and multiple-beat loops were obtained in bradycardia and tachycardia to test for repeatability. These loops were always of a quadrangular-like shape with clockwise rotation. No attempt was made to calibrate the impedance axis in terms of volume. Apparent small volume changes in the isovolumic phases were probably due to ZIV catheter bending and/or movement. It is suggested that DPZ can serve in itself as a complementary evaluation tool of ventricular function by application of different maneuvers (physical, physiological of pharmacological).
左心室功能可用压力-容积图（DPV）进行评估。由于心室容积变化与心室内阻抗（ZIV）变化之间存在关联，我们提出一种由心室内压力（PIV）和ZIV信号得出的图，即DPZ图。该方法在10只麻醉的杂种犬（皮下注射吗啡30 mg/kg和戊巴比妥5 - 7 mg/kg）身上进行了测试。PIV通过在荧光透视引导下经股动脉插入的Millar微尖端导管进行测量。ZIV使用另一根心室内导管，通过四极配置的实验室阻抗仪（均方根恒定电流100 μA，12 kHz）进行测量。还记录了心电图、主动脉压力和基础ZIV，以帮助识别图上不同的心动周期阶段。在心动过缓和心动过速状态下获取了单搏和多搏环，以测试其可重复性。这些环总是呈四边形且顺时针旋转。未尝试根据容积对阻抗轴进行校准。等容相期间明显的小容积变化可能是由于ZIV导管弯曲和/或移动所致。有人提出，通过应用不同的操作（物理、生理或药理学操作），DPZ图本身可作为心室功能的一种补充评估工具。
