Kramer D A, Hamlin R L, Weed H R
Circ Res. 1984 Dec;55(6):788-93. doi: 10.1161/01.res.55.6.788.
The purpose of this study was to discover the cause and magnitude of changes in the body-surface potentials occurring when: (1) fluids of various conductivity were added to the pericardial sac, or (2) the volume of the blood within chambers of the heart was either increased or decreased. Fluids added to the pericardium were physiological saline, whole-blood, and mineral oil. Magnitudes of body-surface potentials were compared to the predictions based on a mathematical eccentric spheres model of the heart and torso developed previously by Rudy and Plonsey. Data demonstrated conclusively that there is a nonlinear relationship between the body-surface potentials and the conductivity of the pericardial layer. This relationship is one in which the body-surface potentials of the anterior chest were found to decrease when conductivity of the pericardial layer was either increased or decreased. These changes in body-surface potentials were caused solely by alterations in the conductivity and volume of the fluid effusate. It was demonstrated that these changes were not caused by any "stretching" or "compression" of the cardiac tissue caused by the altered fluid volumes in and around the heart. Findings were accurately predicted by the eccentric spheres model, thereby confirming the model's usefulness as a predictive instrument. The model provides an explanation for the nonlinear relationship that was exhibited by the data.
（1）向心包腔内添加具有不同电导率的液体；（2）增加或减少心腔内的血液量。添加到心包的液体有生理盐水、全血和矿物油。将体表电位的大小与基于Rudy和Plonsey之前建立的心脏和躯干数学偏心球模型的预测值进行比较。数据确凿地表明，体表电位与心包层的电导率之间存在非线性关系。这种关系表现为，当心包层电导率增加或降低时，前胸的体表电位会降低。体表电位的这些变化完全是由渗出液的电导率和体积变化引起的。结果表明，这些变化并非由心脏内外液体量改变导致的心脏组织“拉伸”或“压缩”引起。偏心球模型准确地预测了研究结果，从而证实了该模型作为一种预测工具的有效性。该模型为数据所呈现的非线性关系提供了解释。
