A NEW METHOD FOR ON-SCREEN ULTRASONOGRAPHIC DETERMINATION OF FETAL CARDIAC AXIS

OBJECTIVE: Our purpose was to develop an ultrasonographic method of us ing multiple electronic calipers for on-screen measurement of fetal ca rdiac axis. STUDY DESIGN: Two hundred low-risk patients who were seen for antenatal ultrasonography were studied. Standard biometry, anatomi c survey, and echocardiography were performed on all fetuses. By use o f a four-chamber view fetal cardiac axis was measured with electronic calipers. A table, derived from a trigonometric formula, was created t o convert the caliper measurements to cardiac axis in degrees. The res ults were compared with a protractor-determined fetal cardiac axis. RE SULTS: All echocardiograms had normal results. Fetal cardiac axis (+/- 2 SD) by the ultrasonographic method was 43 degrees (+/- 16 degrees) versus 43 degrees (+/- 14 degrees) by the protractor method. This diff erence was not significant. CONCLUSION: An on-screen method to determi ne fetal cardiac axis by use of multiple calipers is described. It is comparable to a protractor-measured fetal cardiac axis.