CONTINUOUS STROKE VOLUME AND CARDIAC-OUTPUT FROM INTRAVENTRICULAR DIMENSIONS OBTAINED WITH IMPEDANCE CATHETER
CONTINUOUS STROKE VOLUME AND CARDIAC-OUTPUT FROM INTRAVENTRICULAR DIMENSIONS OBTAINED WITH IMPEDANCE CATHETER
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DOI：
10.1093/cvr/15.6.328
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发表时间：
1981-01-01
影响因子：
10.8
通讯作者：
KOOPS, J
中科院分区：
文献类型：
--
作者：
BAAN, J;JONG, TTA;KOOPS, J
To improve assessment of ventricular function during cardiac catheterization there should be available a continous registration of stroke volume and cardiac output in addition to ventricular pressure. To obtain the desired volumetric quantities a catheter was developed which measures changes in intraventricular dimensions by electrical impedance. The catheter is equipped with 8 electrodes spaced over a distance equal to the long axis of the left ventricle into which it is introduced. A constant current is imposed between the outermost electrodes while the inner 6 are used to measure resistance of volume segments of the blood contained within the ventricular cavity. The difference in resistance at the beginning and end of ejection is proportional to the contribution of each segment to stroke volume, which follows from addition of the segmental terms. Calibration is obtained by measuring electrical conducitivity of a blood sample. The catheter was tested over a 10-fold range of cardiac output, both in vitro, using an artifical heart model, while performance in vivo was evaluated in 12 dogs. Stroke volume and cardiac output from the catheter were compared with flows obtained with an electromagnetic flowmeter. Linear regression analysis showed excellent correlation of cardiac output (r = 0.99, n = 10 in vitro, r = 0.95, n = 126 in vivo) while the regression equations were close to those of identity. Very good correlation (r = 0.98, n = 28) was obtained for stroke volumes on a beat to beat basis during arrhythmia. The catheter, which has great potential for application in man, fulfills its primary aim of continuously recording stroke volume and cardiac output.
