Cardiovascular research
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Cardiovascular research · Jun 1981
Continuous stroke volume and cardiac output from intra-ventricular dimensions obtained with impedance catheter.
To improve assessment of ventricular function during cardiac catheterisation there should be available a continuous registration of stroke volume and cardiac output in addition to ventricular pressure. To obtain the desired volumetric quantities a catheter has been developed which measures changes in intraventricular dimensions by electrical impedance. For this purpose, the catheter is equipped with eight electrodes spaced over a distance equal to the long axis of the left ventricle into which it is introduced. ⋯ In both studies, 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 also obtained for stroke volumes on a beat to beat basis during arrhythmia. It is concluded that the catheter, which has great potential for application in man, fulfills its primary aim of continuously recording stroke volume and cardiac output.