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M-mode echocardiographic examination of the right and left ventricles was performed on 82 normal fetuses between 18 and 41 weeks of gestation. The diameter of the right and left ventricles correlated with the biparietal diameter. The right/left ratio of the ventricular diameters remained constant (1:1) throughout gestation. Fractional shortening and mean circumferential shortening of both ventricles were independent of gestational age. The data presented in this paper will allow the clinician to evaluate abnormal fetal conditions that might affect cardiovascular structure and/or function.

Tetralogy of Fallot has increased in incidence during the past decade. Although abnormalities of the four-chamber screening examination of the fetal heart identifies structural anomalies associated with semilunar and atrioventricular valve hypoplasias, the anomalies associated with tetralogy of Fallot are not as readily identifiable from the four-chamber view alone. This study was designed to determine whether aortic root dilatation, commonly observed in the newborn with tetralogy of Fallot, is a marker for tetralogy of Fallot diagnosed in utero. In 45 normal (control) fetuses the biparietal diameter, head circumference, abdominal circumference, and femur length were measured and M-mode measurements were made of the biventricular outer dimension and aortic root dimension. The aortic root dimension from seven fetuses (18, 19, 20, 23, 32, 33, and 34 weeks' gestation) with tetralogy of Fallot was increased in dimension when compared with cardiac (biventricular outer dimension) and noncardiac biparietal diameter, head and abdomen circumferences, and femur length parameters. In conclusion, incorporation of aortic root imaging with the four-chamber view of the fetal heart during a routine screening examination allows for identification of fetuses with tetralogy of Fallot.

A technique that makes use of real-time-directed M-mode echocardiography is described in which the fetal heart is evaluated for suspected cardiac arrhythmias. Simultaneous M-mode recording of aortic, mitral, or tricuspid valvular leaflet excursion and/or atrioventricular wall motion defines timing relationships between atrial and ventricular systole. With the use of the techniques described in this report, normal as well as abnormal atrioventricular contractions can be quantitated and cardiac arrhythmias accurately defined.

One of the difficulties for the fetal sonographer is the complete elucidation of structural defects of the cardiovascular system that are associated with intracardiac or great vessel flow disturbances. With the recent introduction of Doppler color flow mapping, in which blood flow is displayed in color superimposed on a real-time image, it has been impossible to identify flow disturbances in the pediatric and adult patient. This study was undertaken to determine whether Doppler color flow mapping could be used in the fetus to identify normal and abnormal cardiovascular anatomy. Thirty-five normal and high-risk fetuses were examined between 16 and 40 weeks of gestation. Doppler color flow mapping identified normal and abnormal anatomy (ventricular septal defect, atrial septal defect, endocardial fibroelastosis, dysplastic pulmonary valve, and tricuspid regurgitation). It appears that Doppler color flow mapping will add a new dimension to fetal cardiovascular imaging.

The combination of 2-dimensional real-time and pulsed Doppler echocardiography provides a noninvasive method of measuring blood flow and has been used to study blood flow at the lower thoracic level in the descending aorta of the human fetus. Using these techniques, we evaluated the proportion of cardiac output distributed through the descending aorta in 20 healthy term newborn infants at 1-6 days of age. Blood flow in the ascending aorta was 759 +/- 135 ml/min (mean +/- S.D.) and in the descending aorta 482 +/- 92 ml/min indicating that 63.8% of the left ventricular output is distributed through the descending aorta. Peak systolic and mean blood flow velocities were comparable at the two sites, whereas the diameter of the descending aorta was 19% smaller than that of the ascending aorta. The changes in aortic blood flow were correlated with the changes in aortic diameter.

Forty-one children with advanced chronic rheumatic disease of the mitral valve had preoperative and postoperative hemodynamic studies. Twenty-three cases had open mitral commissurotomy, and 20 had mitral valvular replacement. After surgery the average pulmonary arterial systolic pressure in the group with valve replacement decreased from 78 to 42 mm Hg, the pulmonary vascular resistance decreased from 974 to 313 dynes sec cm 5, and the cardiac index rose from 2.29 to 4.15 L/min sq m. In the group with mitral commissurotomy, the average pulmonary arterial systolic pressure decreased from 90 to 63 mm Hg, the pulmonary vascular resistance decreased from 1,201 to 616 dynes sec cm-5, and the cardiac index rose from 2.5 to 3.5 L/min sq m. While all patients with mitral valve replacement showed a drop in pulmonary arterial pressure, the postoperative pressures were higher after commissurotomy in four patients, two of whom required a second operation of valve replacement. The study shows that in children, even severe degrees of pulmonary hypertension secondary to mitral valve abnormality is corrected.

The aortic root dimension and aortic valve excursion of 43 normal fetuses were recorded with M-mode echocardiography and the measured dimensions correlated with noncardiac measurements (biparietal diameter, head circumference, abdominal circumference, and femur length) and cardiac measurements (diastolic biventricular inner dimension, diastolic left ventricular internal dimension, and mitral valve excursion). The correlation coefficients for the aortic root dimension ranged between 0.87 and 0.95, while those for the aortic valve excursion ranged between 0.78 and 0.87. Regression analysis demonstrated that the best fit of the data was a linear model from which the 5% and 95% confidence limits were computed for individual predictions of aortic root dimension and aortic valve excursion from noncardiac and cardiac measurements.