Nomograms of cardiac morphologic parameters in second trimester obstetric ultrasonography

The purpose of this study is to determine the nomograms of atrium and ventricles in fetuses between 20 and 24 gestational weeks. We measured right and left ventricular widths (RVw and LVw), right and left atrium widths (RAw and LAw), wall thickness of ventricles (RVt and LVt), the ratio of ventricle width, the ratio of atrium width, ventricle wall thickness ratio, heart circumference, thoracic circumference and cardiothoracic ratio of fetuses referred to our department for second trimester routine obstetric ultrasound in 20-24 gestational weeks. Between December 2015 and June 2016, 371 fetuses referred to our department were prospectively evaluated. Twin pregnancies, and fetuses with family history of cardiac disease were excluded study. Of 371, 281 fetuses were included our study. These fetuses underwent detailed fetal cardiac sonographic examination. Our landmark was under the atrioventricular valves in four chamber view during diastole in order to measure the parameters from ventricles and atrium we mentioned above. Nomograms of these parameters were obtained by using logistic regression analysis and one way ANOVA tests. There were a statistically significant difference in RVw, LVw, RAw, LAw, RVt, LVt, right ventricle wall thickness, left ventricle wall thickness, heart circumference, thoracic circumference and cardiothoracic ratio according to gestational age (p=0,024 for cardiothoracic ratio, p<0,001 for other parameters). However, there was no statistically significant difference in ventricle width ratio, atrium with ratio and ventricle wall thickness ratio with respect to gestational age (p=0,958; 0,939 and p= 0,433 respectively). Our results showed that ventricle width ratio and atrium width ratio is almost stable between 20-24 weeks. As the fetus grows, parameters are increased in accordance with gestational age. These nomograms will be beneficial in detection of pathologies and differential diagnosis of congenital heart disease. Also, in some uncertain cases, ratios can be used as practical guide to follow-up. We believe these values should be integrated with other sonographic views such as three vessel view and dynamic functional evaluation findings.