Donofrio, Mary T.

The majority of congenital cardiovascular disease including structural cardiac defects, abnormalities in cardiac function, and rhythm disturbances can be identified prenatally using screening obstetrical ultrasound with referral for fetal echocardiogram when indicated. Diagnosis of congenital heart disease in the fetus should prompt assessment for extracardiac abnormalities and associated genetic abnormalities once parental consent is obtained. Pediatric cardiologists, in conjunction with maternal-fetal medicine, neonatology, and cardiothoracic surgery subspecialists, should counsel families about the details of the congenital heart defect as well as prenatal and postnatal management. Prenatal diagnosis often leads to increased maternal depression and anxiety; however, it decreases morbidity and mortality for many congenital heart defects by allowing clinicians the opportunity to optimize prenatal care and plan delivery based on the specific lesion. Changes in prenatal care can include more frequent assessments through the remainder of the pregnancy, maternal medication administration, or, in selected cases, in utero cardiac catheter intervention or surgical procedures to optimize postnatal outcomes. Delivery planning may include changing the location, timing or mode of delivery to ensure that the neonate is delivered in the most appropriate hospital setting with the required level of hospital staff for immediate postnatal stabilization. Based on the specific congenital heart defect, prenatal echocardiogram assessment in late gestation can often aid in predicting the severity of postnatal instability and guide the medical or interventional level of care needed for immediate postnatal intervention to optimize the transition to postnatal circulation.

Background: Long-QT syndrome (LQTS), an inherited cardiac repolarization disorder, is an important cause of fetal and neonatal mortality. Detecting LQTS prenatally is challenging. A fetal heart rate (FHR) less than third percentile for gestational age is specific for LQTS, but the sensitivity is only ≈50%. Left ventricular isovolumetric relaxation time (LVIRT) was evaluated as a potential diagnostic marker for fetal LQTS. Methods and Results: LV isovolumetric contraction time, LV ejection time, LVIRT, cycle length, and FHR were measured using pulsed Doppler waveforms in fetuses. Time intervals were expressed as percentages of cycle length, and the LV myocardial performance index was calculated. Single measurements were stratified by gestational age and compared between LQTS fetuses and controls. Receiver-operator curves were performed for FHR and normalized LVIRT (N-LVIRT). A linear mixed-effect model including multiple measurements was used to analyze trends in FHR, N-LVIRT, and LV myocardial performance index. There were 33 LQTS fetuses and 469 controls included. In LQTS fetuses, the LVIRT was prolonged in all gestational age groups ( P <0.001), as was the N-LVIRT. The best cutoff to diagnose LQTS was N-LVIRT ≥11.3 at ≤20 weeks (92% sensitivity, 70% specificity). Simultaneous analysis of N-LVIRT and FHR improved the sensitivity and specificity for LQTS (area under the curve=0.96; 95% confidence interval, 0.82–1.00 at 21–30 weeks). N-LVIRT, LV myocardial performance index, and FHR trends differed significantly between LQTS fetuses and controls through gestation. Conclusions: The LVIRT is prolonged in LQTS fetuses. Findings of a prolonged N-LVIRT and sinus bradycardia can improve the prenatal detection of fetal LQTS.