Right Atrial Dysfunction in the Fetus with Severely Regurgitant Tricuspid Valve Disease: A Potential Source of Cardiovascular Compromise.

BACKGROUND: In severe right heart obstruction (RHO), redistribution of cardiac output to the left ventricle (LV) is well tolerated by the fetal circulation. Although the same should be true of severely regurgitant tricuspid valve disease (rTVD) with reduced or no output from the right ventricle, affected fetuses more frequently develop hydrops or suffer intrauterine demise. We hypothesized that right atrium (RA) function is altered in rTVD but not in RHO, which could contribute to differences in outcomes. METHODS: Multi-institutional retrospective review of fetal echocardiograms performed over a 10-year period on fetuses with rTVD (Ebstein's anomaly, tricuspid valve dysplasia) or RHO (pulmonary atresia/intact ventricular septum, tricuspid atresia) and a healthy fetal control group. Offline velocity vector imaging and Doppler measurements of RA size and function and LV function were made. RESULTS: Thirty-four fetuses with rTVD, 40 with RHO, and 79 controls were compared. The rTVD fetuses had the largest RA size and lowest RA expansion index, fractional area of change, and RA indexed filling and emptying rates compared with fetuses with RHO and controls. The rTVD fetuses had the shortest LV ejection time and increased Tei index with a normal LV ejection fraction. RA dilation (odds ratio, 1.27; 95% CI, 1.05-1.54) and reduced indexed emptying rate (odds ratio, 2.49; 95% CI, 1.07-5.81) were associated with fetal or neonatal demise. CONCLUSIONS: Fetal rTVD is characterized by more severe RA dilation and dysfunction compared with fetal RHO and control groups. RA dysfunction may be an important contributor to reduced ventricular filling and output, potentially playing a critical role in the worsened outcomes observed in fetal rTVD.

Effectiveness of prenatal screening for congenital heart disease: assessment in a jurisdiction with universal access to health care.

BACKGROUND: Neonates with certain forms of severe congenital heart disease (CHD) diagnosed prenatally might have better outcomes in comparison with those diagnosed after birth. The proportion of prenatally detected neonates with severe CHD and the effect of prenatal diagnosis on clinical outcomes have not been previously investigated in Canada. METHODS: We retrospectively studied infants in Alberta, Canada, who required surgical or catheter intervention for CHD at younger than 1 year of age, between January 2007 and December 2010, and pregnancy terminations affected by CHD. RESULTS: Of the 374 subjects identified (327 infants, 47 pregnancies with termination), 188 (50%) were detected prenatally. Failure of prenatal diagnosis was associated with anomalies not involving the 4-chamber view on ultrasound (odds ratio, 1.86; 95% confidence interval, 1.48-2.35; P < 0.001) and region of residence (P = 0.04). Prenatal detection was associated with fewer days to hospital admission (P < 0.001), fewer days to surgery (P = 0.003), and greater use of prostaglandins (P = 0.001). Infants diagnosed prenatally who underwent surgery within 15 days of age had higher preductal O2 saturations (P = 0.04), fewer days to admission (P = 0.03), and less frequently required preoperative intubation (P = 0.004), and inotropes (P = 0.001). Pregnancy termination occurred among 49% of fetuses detected before 24 weeks' gestation. CONCLUSIONS: Only 50% of fetuses and/or neonates with severe CHD managed in Alberta have a prenatal diagnosis. The likelihood of prenatal detection is influenced by the status of the 4-chamber view on ultrasound and the region of maternal residence indicating heterogeneous access to fetal echocardiography within Alberta. Prenatal detection might improve clinical outcomes for neonates with severe CHD.

Antegrade late diastolic arterial blood flow in the fetus: insight into fetal atrial function.

OBJECTIVE: The purpose of this study was to examine the presence and frequency of antegrade late diastolic arterial blood flow (ALDAF) in the fetus and to determine its contribution to cardiac output. STUDY DESIGN: We evaluated the presence of ALDAF in 457 fetal and 21 postnatal echocardiograms. The timing of ALDAF to the ventricular systolic Doppler recording (ALDAF-V) was compared with the mechanical atrioventricular interval and, in neonates, the electrical PR interval. Velocity time integrals of ALDAF and the ventricular systolic Doppler signals were measured, and the percent contribution of ALDAF was calculated. RESULTS: ALDAF was observed in 365 of 457 studies and included all <11 weeks' gestations. Strong correlation between ALDAF-V, atrioventricular interval, and electrical PR interval suggests that ALDAF coincides with atrial contraction. ALDAF contributed substantially to cardiac output in early gestation with later decline. CONCLUSION: ALDAF results from atrial contraction. Increasing gestational age results in less ALDAF, and reduced ALDAF contribution to cardiac output likely due to improved diastolic function.

Observed prevalence of congenital heart defects from a surveillance study in China.

OBJECTIVES: The purpose of this study was to estimate the prevalence of major and minor congenital heart defects among fetuses and neonates using sonography in a general population of 4 areas surrounding Shanghai, China. METHODS: Pregnant women were recruited between April 2004 and December 2005 in Jiaxing City, Suzhou City, Changshu County, and Haining County. All participants could have 3 sonographic examinations performed by specially trained physicians regardless of medical indication: a fetal sonographic screen and fetal echocardiography between 20 and 28 weeks' gestation and neonatal echocardiography. Diagnoses of congenital heart defects were made on the basis of review of all available scans by an international group of experts in pediatric cardiology. Prevalence rates were calculated per 1000 births. RESULTS: Among 4006 scanned fetuses and neonates, there were 75 congenital heart defects, including 12 major defects. The observed prevalence for all congenital heart defects was 18.7 (95% confidence interval, 14.8-23.5) per 1000 births, and the prevalence for major defects was 3.0 (95% confidence interval, 1.6-5.2) per 1000 births. The most common defects were ventricular septal defects (n = 47 [62.7%]), atrial septal defects (n = 14 [18.7%]), tetralogy of Fallot (n = 4 [5.3%]), and hypoplastic left heart syndrome (n = 3 [4.0%]). CONCLUSIONS: The prevalence of all congenital heart defects in the 4 areas of China studied was higher than that reported in other countries, with ventricular septal defects being the most frequent defects. Our data likely reflect a better estimate of the total prevalence of congenital heart defects in China than reported previously.

Early fetal echocardiography--a reliable prenatal diagnosis tool.

OBJECTIVE: This study was undertaken to evaluate the feasibility and to report the detection rate of cardiac anomalies with fetal echocardiography before 16 weeks' gestation. STUDY DESIGN: This is a retrospective and prospective study of 160 early fetal echocardiograms. The mean gestational age was 13.5 weeks' gestation (range 11-15+6). All women had a repeat echocardiogram at 18 weeks' gestation and pregnancy outcome was obtained. RESULTS: In all cases, a cardiac 4-chamber view was obtained. The atrioventricular valves were accurately seen in 154 (96%) cases; the ascending aorta and main pulmonary artery were visualized in 152 cases (95%). Overall, a satisfactory cardiac examination was feasible in 152 of cases (95%). There were 20 cardiac defects in this cohort (12.5%), 14 showed abnormalities at the time of the early ultrasound, whereas 6 were reported as normal. The sensitivity of early fetal echocardiography in this high-risk population was 70%, specificity 98%, positive predictive value 87.5%, and negative predictive value 96%. CONCLUSION: The fetal heart can be examined early in pregnancy and a significant proportion of major cardiac defects identified.