Determination of cardiac output by echocardiography

To determine cardiac output using a non-invasive manner, we examined correlations between cardiac output values determined by ten different kinds of echocardiography and those determined by the thermodilution method. With respect to the M-mode method, one of the rotary ellipsoid approximation methods using a short axial section at the papillary muscular level, namely the GIBSON method, showed the highest correlation with the thermodilution method (r = 0.84; p < 0.01). Among the Doppler mode method, the highest correlation (r = 0.93; p < 0.01) was exhibited by the method in which the area of the luminal section of the outflow tract was accurately measured using a trace method on a short axial cross section of the tract flowing out of the left ventricle. These findings suggest that it is possible to determine cardiac output by echocardiography in the same was as with the thermodilution method. Moreover, non-invasive determination methods using echocardiography have been confirmed to be highly beneficial in clinical settings.