PERINATAL CARDIAC FUNCTIONAL ADAPTATION IN HYPOPLASTIC LEFT HEART SYNDROME: A LONGITUDINAL ANALYSIS.

BACKGROUND: The perinatal transition is characterized by acute changes in cardiac loading. Compared to normal newborn combined cardiac output (CCO), single right ventricular (RV) output of neonates with hypoplastic left heart syndrome (HLHS) is markedly greater. We sought to examine the mechanisms of cardiac adaptation which facilitate this perinatal transition from late fetal to early neonatal life in HLHS. METHODS: Prospectively recruited pregnancies complicated by fetal HLHS (n=35) and health controls (Ctrl, n=17) underwent serial echocardiography in late gestation (38±1weeks) and 6, 24 and 48 hours after birth. Cardiac function was assessed using conventional, tissue Doppler and speckle tracking echocardiography. RESULTS: Term HLHS fetuses had an RV output (RVCO) comparable to Ctrl CCO via higher stroke volume (SV). Compared to both left ventricular (LV) and RV indices of Ctrls, they exhibited a globular and dilated RV with reduced relative wall thickness (RWT) [RWT: 0.40±0.08 vs. 0.49±0.10, p<0.01], increased Tei index' [HLHS vs. Ctrl LV/Ctrl RV: sphericity index (SI): 0.9±0.25 vs. 0.5±0.10/0.6±0.11, RV area index: 28±6cm2/m2 vs. 15±3cm2/m2/17±5cm2/m2, Tei index': 0.65±0.11 vs. 0.43±0.07/0.45±0.09, all p<0.0001]. HLHS neonates generated elevated RVCO compared to Ctrl CCO via higher heart rate and SV, with further RV dilatation, increased longitudinal systolic strain at 48h [-17±4% vs. -14±3%/-14±5%] with reduced circumferential and rotational myocardial deformation and altered diastolic function. HLHS neonates also demonstrated right atrial (RA) enlargement with increased longitudinal strain: 6h (33±12% vs. 26±6%), 24h (37±15% vs. 26±13%), 48h (38±11% vs. 24±13%), p<0.0001. CONCLUSIONS: Term HLHS fetuses exhibit altered RV geometry and RV systolic and diastolic functional parameters. After birth, further alterations in these cardiac parameters likely reflect adaptation to acutely altered RV loading from increasing cardiac output and pulmonary artery flow demands.

A Comparison of Perinatal Circulatory Transition in Critical Right and Left Heart Obstructive Lesions.

BACKGROUND: During perinatal transition in hypoplastic left heart syndrome (HLHS) reduced systemic (Qs) and cerebral blood flow and increased pulmonary flow (Qp) is observed, contributing to hemodynamic instability. In the current study, we explored whether similar or discordant perinatal changes occur in critical pulmonary outflow obstruction (POFO), when compared to HLHS and healthy controls. METHODS: Echocardiography was prospectively performed at 36-39 gestational weeks and then serially from 6-96 hours after birth prior to cardiac intervention. The combined cardiac output (CCO) superior vena cava (SVC), Qs and Qp flow-rates, and resistance indices (RI) in middle cerebral artery (MCA), celiac and superior mesenteric arterial were compared between the three groups. RESULTS: In fetal POFO (n=19) and HLHS (n=31), CCO was comparable to controls (n=21) due to elevated stroke volume, but CCO in POFO was lower compared to HLHS (p<0.01). Compared to controls, POFO CCO was lower at 6 hours post-delivery, but comparable at 24-96 hours. In contrast, from 6-96 hours the HLHS group had higher CCO than POFO and controls. Compared to controls, both POFO and HLHS neonates had lower Qs and SVC flow (POFO 24 hours (p<0.001), HLHS 6-hour Qs and 6-24-hour SVC flow). Compared to controls, Qp was increased in POFO at 48-96 hours (p< 0.05) and in HLHS at all time points (P<0.001). Compared to fetal MCARI, postnatal MCARI was acutely higher in both POFO and HLHS, whereas, in controls, it tended to decrease postnatally. Celiac artery RI and superior mesenteric artery pulsatility index were higher in POFO and HLHS from 6 to 48 hours versus controls. CONCLUSION: POFO and HLHS demonstrate divergent acute hemodynamic changes in the early neonatal period with early decreased CCO in POFO and increased CCO in HLHS. Both demonstrate early compromise in Qs and SVC (cerebral flow) and ongoing altered splanchnic flow.

Predicting High-Risk Fetal Cardiac Disease Anticipated to Need Immediate Postnatal Stabilization and Intervention with Planned Pediatric Cardiac Operating Room Delivery.

BACKGROUND: Distances between delivery and cardiac services can make the care of fetuses with cardiac disease at risk of acute cardiorespiratory instability at birth a challenge. In 2013 we implemented a fetal echocardiography-based algorithm targeting fetuses considered high risk for acute cardiorespiratory instability at ≤2 hours of birth for delivery in our pediatric cardiac operating room of our children's hospital, and, herein, examine our experience. METHODS AND RESULTS: We reviewed maternal and postnatal medical records of all fetuses with cardiac disease encountered January 2013 to March 2022 considered high risk for acute cardiorespiratory instability. Secondary analysis was performed including all fetuses with diagnoses of d-transposition of the great arteries/intact ventricular septum (d-TGA/IVS) and hypoplastic left heart syndrome (HLHS) encountered over the study period. Forty fetuses were considered high risk for acute cardiorespiratory instability: 15 with d-TGA/IVS and 7 with HLHS with restrictive atrial septum, 4 with absent pulmonary valve syndrome, 3 with obstructed anomalous pulmonary veins, 2 with severe Ebstein anomaly, 2 with thoracic/intracardiac tumors, and 7 others. Pediatric cardiac operating room delivery occurred for 33 but not for 7 (5 with d-TGA/IVS, 2 with HLHS with restrictive atrial septum). For high-risk cases, fetal echocardiography had a positive predictive value of 50% for intervention/extracorporeal membrane oxygenation/death at ≤2 hours and 70% at ≤24 hours. Of "low-risk" cases, 6/46 with d-TGA/IVS and 0/45 with HLHS required intervention at ≤2 hours. Fetal echocardiography for predicting intervention/extracorporeal membrane oxygenation/death at ≤2 hours had a sensitivity of 67%, specificity 93%, and positive and negative predictive values of 80% and 87%, respectively, for d-TGA/IVS, and 100%, 95%, 71%, and 100% for HLHS, respectively. CONCLUSIONS: Fetal echocardiography can predict the need for urgent intervention in a majority with d-TGA/IVS and HLHS and in half of the entire spectrum of high-risk cardiac disease.

Accuracy of Fetal Echocardiography in Defining Anatomic Details: A Single-Institution Experience over a 12-Year Period.

BACKGROUND: Fetal echocardiography has evolved over four decades, now permitting the prenatal diagnoses of most major congenital heart disease (CHD). To identify areas for targeted improvement, the authors explored the diagnostic accuracy of fetal echocardiography in defining major fetal CHD. METHODS: All fetuses with major fetal CHD (11 subtypes) at a single institution between 2007 and 2018 were identified (n = 827). Fetal echocardiography reports were compared with postnatal imaging and surgical or autopsy reports, and findings were categorized as follows: category 1, no errors; category 2, minor errors without impact on care, considered "accurate"; category 3, errors with minor impact on surgical approach; and category 4, errors with major impact on neonatal care or outcomes, considered "inaccurate." In addition, the contributions of era, gestational age at first fetal echocardiography, serial fetal echocardiography, maternal weight, and reviewer level of training were examined. RESULTS: Of 589 fetuses with autopsy or postnatal confirmation, accurate diagnoses were made in 530 (90%). The highest rates of accuracy were observed in univentricular hearts (97.6%; 95% CI, 87.4%-99.6%), tetralogy of Fallot (97.2%; 95% CI, 90.0%-99.2%), and transposition of the great arteries (96.1%; 95% CI, 89.2%-98.6%), and the lowest were observed in double-outlet right ventricle (81.1%; 95% CI, 70.4%-88.6%), truncus arteriosus (72.7%; 95% CI, 51.8%-86.8%), and heterotaxy (71.1%; 95% CI, 56.6%-82.2%). Greater accuracy was associated with later diagnostic era (2012-2018, P = .026), first fetal echocardiography at ≤25 weeks (P = .028), and formal fetal cardiology training of the reviewer (P = .001). Maternal pre-pregnancy weight did not affect accuracy. CONCLUSIONS: The diagnostic accuracy of fetal echocardiography for major CHD is high, particularly in the hands of fetal cardiology-trained practitioners. There are lesion-specific as well as general modifiable and nonmodifiable factors that affect diagnostic accuracy.

Extra-cardiac diagnoses and postnatal outcomes of fetal tetralogy of fallot.

OBJECTIVE: Past studies of fetal tetralogy of fallot (ToF) have reported extra-cardiac anomalies (ECAs) in 17%-45%, genetic syndromes in as low as 20% and poor postnatal outcomes. This study sought to examine these factors in a contemporary cohort. METHODS: A retrospective review examining 83 fetuses with ToF diagnosed 2012-2019. Referral indication, ToF subtype, additional cardiac, extra-cardiac and genetic diagnoses, pregnancy outcomes and survival were documented. RESULTS: The mean gestational age at diagnosis was 23 ± 4 weeks. Of 94% (78/83) with genetic testing (GT), 30% (23/78, 95%CI 21%-40%) had genetic anomalies (GA), including Trisomy 21 (39%, 9/23), 22q11 deletion (35%, 8/23), Trisomy 13 or 18 (17%, 4/23) and 9% (2/23) others. A further 4% (3/78) had VACTERL association. Forty-one percent (34/83, 95%CI 31%-52%) had ≥1 major ECA of whom 41% (14/34) also had a genetic anomaly. OUTCOMES: 22% (18/83) pregnancy termination, 5% (4/83) intrauterine death and 72% (60/83) live birth. Of live births, 3% (2/60) experienced neonatal death, 7% late death (4/60) and 90% (54/60) were alive at last follow-up (mean age 3.5 ± 2.4 years). CONCLUSION: In a cohort of fetuses with ToF and high rates of GT, compared to previous reports, GA were more common and there were similar rates of ECAs.

The Diagnostic Yield of Fetal Echocardiography Indications in the Current Era.

BACKGROUND: The aim of this study was to examine the diagnostic yield of current fetal echocardiography (FE) indications representing a recent era. METHODS: FE reports of all pregnancies referred to two provincial FE programs from 2009 to 2018 were examined, identifying the indication for FE (14 categories), gestational age at referral, and whether there was no fetal heart disease (FHD), mild or possible FHD (e.g., simple ventricular septal defect, possible coarctation), or moderate or severe FHD. RESULTS: Over the study period, there were 19,310 unique FE referrals in Alberta (23.3 ± 5.4 weeks' gestation), including 1,907 (9.9%) with moderate or severe and 654 (3.4%) with mild or possible FHD. The most common referral indications included extracardiac pathology or markers (29.7%), maternal diabetes (18.3%), suspected FHD (17.7%), and family history of heart defects (17.7%). The highest yield for moderate or severe FHD was suspected FHD (41.1%; 95% CI, 39.4%-42.7%), followed by suspected or confirmed genetic disorder (15.4%; 95% CI, 12.6%-18.2%), twins or multiples (10.6%; 95% CI, 8.7%-12.5%), oligohydramnios (8.0%; 95% CI, 4.1%-11.9%), extracardiac pathology or markers (6.4%; 95% CI, 5.8%-7.1%), and heart not well seen (5.8%; 95% CI, 4.0%-7.6%). Lowest yields were observed for maternal diabetes (2.2%; 95% CI, 1.7%-2.7%) and family history of heart defects (1.7%; 95% CI, 1.3%-2.2%). Excluding suspected FHD, with two or more FE indications, all other indications demonstrated significant increases in yield of mild or possible (3.5% vs 1.9%, P < .001) and moderate or severe (7.2% vs 2.9%, P < .001) FHD. CONCLUSIONS: Suspected FHD provides the highest diagnostic yield of moderate or severe FHD. In contrast, maternal diabetes and family history of heart defects, among the most common referral indications, had diagnostic yields approaching general population risks. Even in the absence of suspected FHD, having two or more referral indications importantly increases the diagnostic yield of all other FE indications.

Fetal double outlet right ventricle without heterotaxy syndrome: Diagnostic spectrum, associated extracardiac pathology and clinical outcomes.

OBJECTIVES: To document the clinical spectrum and outcomes of fetal double outlet right ventricle (DORV) without heterotaxy in a recent diagnostic era. METHODS: Prenatal cases of DORV consecutively diagnosed from 2007 to 2018 were retrospectively identified. Clinical records, including details regarding genetic testing and pre and postnatal imaging were reviewed. RESULTS: DORV was diagnosed in 99 fetuses without heterotaxy. The most common anatomic subtype was subaortic ventricular septal defect (VSD) and normally related great arteries with (n = 45, 45%) or without (n = 13, 13%) pulmonary stenosis. The remainder had a subpulmonic VSD with transposed great arteries (n = 15, 15%), atrioventricular valve atresia (n = 24, 24%), or remote VSD (n = 2, 2%). A genetic diagnosis was found in 32 (34%) of 93 tested. Major extracardiac anomalies were found in 40 (40%), including 17/24 (71%) with and 22/69 (32%) without an abnormal karyotype, with VACTERL association in 9. Genetic and/or extracardiac pathology was identified in 37/58 (64%) with a subaortic VSD, 5/15 (33%) with a subpulmonic VSD, 9/24 (38%) of those with AV valve atresia and 2/2 (100%) with a remote VSD. A genetic abnormality was a significant predictor of fetal demise (9/37 vs 1/62 p < 0.01) or pregnancy termination (12/35 vs 9/64 p = 0.03). CONCLUSIONS: Fetal DORV is associated with a high rate of genetic abnormalities and extracardiac pathology. The presence of genetic abnormalities impacts prenatal outcomes and parental decision-making.

Impact of Socioeconomic Status, Race and Ethnicity, and Geography on Prenatal Detection of Hypoplastic Left Heart Syndrome and Transposition of the Great Arteries.

BACKGROUND: Prenatal detection (PND) has benefits for infants with hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA), but associations between sociodemographic and geographic factors with PND have not been sufficiently explored. This study evaluated whether socioeconomic quartile (SEQ), public insurance, race and ethnicity, rural residence, and distance of residence (distance and driving time from a cardiac surgical center) are associated with the PND or timing of PND, with a secondary aim to analyze differences between the United States and Canada. METHODS: In this retrospective cohort study, fetuses and infants <2 months of age with HLHS or TGA admitted between 2012 and 2016 to participating Fetal Heart Society Research Collaborative institutions in the United States and Canada were included. SEQ, rural residence, and distance of residence were derived using maternal census tract from the maternal address at first visit. Subjects were assigned a SEQ z score using the neighborhood summary score or Canadian Chan index and separated into quartiles. Insurance type and self-reported race and ethnicity were obtained from medical charts. We evaluated associations among SEQ, insurance type, race and ethnicity, rural residence, and distance of residence with PND of HLHS and TGA (aggregate and individually) using bivariate analysis with adjusted associations for confounding variables and cluster analysis for centers. RESULTS: Data on 1862 subjects (HLHS: n=1171, 92% PND; TGA: n=691, 58% PND) were submitted by 21 centers (19 in the United States). In the United States, lower SEQ was associated with lower PND in HLHS and TGA, with the strongest association in the lower SEQ of pregnancies with fetal TGA (quartile 1, 0.78 [95% CI, 0.64-0.85], quartile 2, 0.77 [95% CI, 0.64-0.93], quartile 3, 0.83 [95% CI, 0.69-1.00], quartile 4, reference). Hispanic ethnicity (relative risk, 0.85 [95% CI, 0.72-0.99]) and rural residence (relative risk, 0.78 [95% CI, 0.64-0.95]) were also associated with lower PND in TGA. Lower SEQ was associated with later PND overall; in the United States, rural residence and public insurance were also associated with later PND. CONCLUSIONS: We demonstrate that lower SEQ, Hispanic ethnicity, and rural residence are associated with decreased PND for TGA, with lower SEQ also being associated with decreased PND for HLHS. Future work to increase PND should be considered in these specific populations.

Prenatal features, associated co-morbidities and clinical course of agenesis of the ductus venosus in the current era.

OBJECTIVES: Agenesis of the ductus venosus (ADV) has been associated with additional anomalies in up to 83% of cases. We sought to investigate characteristics, co-morbidities and outcomes of ADV in the current era. We hypothesized that rates of cardiac and non-cardiac diagnoses and survival would be higher, due to advances in genetic testing, prenatal diagnosis and surveillance. METHODS: A retrospective series of cases diagnosed at our institution from 2007 to 2018 were identified by searching our database. Cardiac and obstetric charts were reviewed for cardiac and extra-cardiac anomalies, genetic results and outcomes. RESULTS: Fourteen cases were diagnosed at a mean gestational age of 23.9 weeks (range 13-33). All had associated genetic, cardiac or extra-cardiac anomalies. Eight (57%) had cardiac anomalies and one other developed cardiomyopathy by 6 months. Extra-cardiac anomalies were present in 93% (13/14) and genetic diagnoses made in 75% (6/8) of those tested. Cardiac output Z-scores were >2 in 60% (6/10) prior to delivery. Two had hydrops, there was one intra-uterine death, 13 live-births and two neonatal deaths. CONCLUSION: Our cohort had more associated diagnoses and a lower mortality than previously reported. In our experience, high output occurs frequently, however with a relatively low risk of hydrops and intrauterine death.

Predicting Post-Fontan Length of Stay: The Limits of Measured Variables.

Post-operative length of stay (LOS) is an important metric for both healthcare providers and patients and their families. Predicting LOS is a challenge as it is sensitive to multitudinous patient and system factors. All subjects undergoing a Fontan from 1996-2016 who survived to hospital discharge were included. Details about the pre-operative status, operative conduct, and post-operative course of each patient were obtained. The association between patient characteristics and post-Fontan LOS were determined using stepwise multivariable regression models. Of 320 subjects who underwent a Fontan, 314 (98.1%) survived to hospital discharge. Median age at Fontan was 3.3 years (IQR 2.8, 4.0) and the most common underlying diagnosis was hypoplastic left heart syndrome (106, 33.8%). Median post Fontan LOS was 11 days (IQR 8, 17). Univariable risk factors for longer LOS included number of previous surgeries, post-Glenn LOS, cardiopulmonary bypass time, post-operative chylothorax, and failure to extubate in the operating room (all p < 0.05). In multivariable models, number of previous operations, extubation in the operating room, and postoperative complications predicted LOS (R2 = 0.5185 for full model). The proportion of patients discharged on week days (14.7-18.8% per day) was significantly higher than the proportion discharged on weekend days (5.1-9.9% per weekend day). Pre-operative variables have limited use in predicting post-Fontan length of stay. The most important predictors of post-operative LOS are extubation in the operating room and the occurrence of post-operative complications. However, a significant proportion of variability in LOS was not explained by available measurable variables.

Evolution of the fetal atrioventricular interval from 6 to 40 weeks of gestation

Doppler-based methods of estimating the atrioventricular interval are commonly used as a surrogate for the electrical PR in fetuses at risk of conduction abnormalities; however, to date, normal values for the fetal atrioventricular interval and an understanding of the evolution of its components in the late first trimester are lacking. We sought to investigate changes in the fetal atrioventricular interval from the first trimester to 40 weeks gestational age, and to explore functional and electrophysiological events that potentially impact its evolution. We prospectively examined healthy pregnancies by fetal echocardiography from 6 to 40 weeks' gestational age. The atrioventricular interval, heart rate, isovolumic contraction time, and A-wave duration were measured from simultaneous ventricular inflow-outflow Doppler tracings. Regression analysis was used to examine relations with gestational age, and linear relations with heart rate were assessed by Pearson's correlation coefficient. Data were collected in 305 fetuses from 279 pregnancies. Atrioventricular interval demonstrated an inverse relation with heart rate (r = -0.45, p <0.0001), dramatically decreasing before 10 weeks and slowly increasing thereafter. Between 6 and 9 weeks, isovolumic contraction time acutely decreasedapproaching 0, thereafter minimally increasing to term. In contrast, from 6 weeks, the A-wave duration linearly increased through gestation, and negatively correlated with heart rate (r = -0.62, p <0.0001). In conclusion, we have established normal measures of the atrioventricular interval from 6 to 40 weeks' gestational age. Before 10 weeks, a prolonged atrioventricular interval in healthy fetuses largely reflects the lengthened isovolumic contraction time which is likely influenced by the evolution of ventricular function and afterload. (AU)

Evolution of the Fetal Atrioventricular Interval from 6 to 40 Weeks of Gestation.

Doppler-based methods of estimating the atrioventricular interval are commonly used as a surrogate for the electrical PR in fetuses at risk of conduction abnormalities; however, to date, normal values for the fetal atrioventricular interval and an understanding of the evolution of its components in the late first trimester are lacking. We sought to investigate changes in the fetal atrioventricular interval from the first trimester to 40 weeks gestational age, and to explore functional and electrophysiological events that potentially impact its evolution. We prospectively examined healthy pregnancies by fetal echocardiography from 6 to 40 weeks' gestational age. The atrioventricular interval, heart rate, isovolumic contraction time, and A-wave duration were measured from simultaneous ventricular inflow-outflow Doppler tracings. Regression analysis was used to examine relations with gestational age, and linear relations with heart rate were assessed by Pearson's correlation coefficient. Data were collected in 305 fetuses from 279 pregnancies. Atrioventricular interval demonstrated an inverse relation with heart rate (r = -0.45, p <0.0001), dramatically decreasing before 10 weeks and slowly increasing thereafter. Between 6 and 9 weeks, isovolumic contraction time acutely decreased approaching 0, thereafter minimally increasing to term. In contrast, from 6 weeks, the A-wave duration linearly increased through gestation, and negatively correlated with heart rate (r = -0.62, p <0.0001). In conclusion, we have established normal measures of the atrioventricular interval from 6 to 40 weeks' gestational age. Before 10 weeks, a prolonged atrioventricular interval in healthy fetuses largely reflects the lengthened isovolumic contraction time which is likely influenced by the evolution of ventricular function and afterload.

Prenatal Detection, Comorbidities, and Management of Vascular Rings.

The 3-vessel and trachea view is now integrated into obstetrical screening and facilitates prenatal detection of vascular rings. We examined trends in prenatal detection, associated cardiac and extracardiac anomalies, and surgical management in this population. We reviewed a population-based cohort of pediatric vascular ring patients diagnosed prenatally and postnatally between 2002 and 2017 in Alberta, Canada. Of 106 cases, 28 (26%) had a prenatal diagnosis. Prenatal detection increased over time: 0/29 from 2002 to 2009, 4/28 (14%) from 2009 to 2011, 7/23 (30%) from 2012 to 2014, and 17/26 (65%) from 2015 to 2017 (p <0.01). The prenatal group more commonly had right aortic arch/left ductus/aberrant left subclavian artery (24/28vs 53/78, p = 0.04) and associated cardiac pathology (18/28vs 33/78, p = 0.05). The rate of genetic anomalies was overall higher than previously reported (34%) and did not differ between groups (11/28vs 25/78, p = 0.48). Those with a prenatal diagnosis were less likely to require cross-sectional imaging (9/28vs 48/78, p <0.01), modifying the vascular ring subtype diagnosis in 2 patients. Surgical intervention was common and did not differ between groups (24/28vs 66/78, p = 0.89). In conclusion, prenatal detection of vascular rings has increased. Despite differences in vascular ring subtype and associated cardiac pathology, the incidence of genetic anomalies and need for surgical intervention is not associated with timing of diagnosis. Genetic counseling should be universally offered. The diagnostic accuracy of echocardiography suggests additional imaging may not be routinely required.

The Incremental Benefit of Color Tissue Doppler in Fetal Arrhythmia Assessment.

BACKGROUND: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques. METHODS: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared. RESULTS: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half. CONCLUSIONS: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies.

Early fetal echocardiography.

OBJECTIVES: To explore the technical aspects and clinical utility of early fetal echocardiography and screening of the fetal heart in early pregnancy. Also, to document differences in cardiac structure and function which can be demonstrated in the late first/early second trimesters. METHODS: In addition to summarizing our own experiences of late first/early second trimester fetal echocardiography, we reviewed the literature to explore clinical indications for, technical aspects, safety, accuracy, strengths and weaknesses of early fetal echocardiography. RESULTS: In the current era, an increasing number of fetuses are identified as being at risk of congenital heart disease from as early as the late first trimester. In experienced hands, early fetal echocardiography can pick up a high proportion of congenital heart disease with good reliability for the majority of lesions. Early fetal echocardiography is relatively poor at assessing pulmonary veins, the atrioventricular valves and lesions that typically occur later or progress during the course of pregnancy. There is increasing interest in widespread implementation of an early obstetric anomaly screen which includes an assessment of the fetal heart for all pregnancies. There are a variety of hemodynamic differences in the late first/early second trimester compared with later in pregnancy. CONCLUSION: Early fetal echocardiography is has become an established tool for detection of congenital heart disease. It affords opportunities to learn about the true spectrum and progression of congenital heart disease in-utero. Operators should be mindful of safety issues, technical aspects and hemodynamic findings which differ when performing echocardiograms at this stage of pregnancy.

The incremental benefit of color tissue doppler in fetal arrhythmia assessment

BACKGROUND: Accurate fetal arrhythmia diagnosis is key for effective management. Standard echo-based techniques (M-mode and spectral Doppler) require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Little data exists on the application of cTDI in fetal rhythm assessment. OBJECTIVE: We sought to determine the benefit of color tissue Doppler imaging (cTDI) in fetal arrhythmia assessment over conventional fetal echo techniques. METHODS: Pregnancies with a diagnosis of fetal arrhythmia were prospectively recruited to undergo cTDI following fetal echocardiography. Multiple cycle 4-chamber clips in any orientation were recorded (frame rates >180 fps). With offline analysis, sample-volumes were placed on atrial (A) and ventricular (V) free walls with simultaneous recordings. A and V rates, intervals and relationships were evaluated. RESULTS: Arrhythmias were assessed in 45 fetuses by cTDI at 15-39 weeks and included: 11 atrial and 5 ventricular ectopic beats; 18 supraventricular tachyarrhythmias (SVT) including ectopic atrial tachycardia in 11, AV re-entry SVT in 4, atrial flutter (AF) in 2, intermittent AF and junctional ectopic rhythm in 1; ventricular tachycardias in 3; 8 bradycardias or AV conduction pathology including complete AV block (AVB) in 5, 1 AVB evolving into complete AVB in 1, 2 AVB in 1, sinus bradycardia in 1. Arrhythmia diagnosis by cTDI could be made irrespective of orientation of the fetus, after training, within 10-15 minutes. cTDI findings concurred with the diagnosis by standard techniques in 95% of cases and added new findings in 29%. In 5%, cTDI provided a new diagnosis, confirmed postnatally. In cases with SVT, cTDI permitted assessment of A-V and V-A intervals elucidating arrhythmia mechanism in all, whereas standard techniques had failed to define mechanism in 45%. CONCLUSION: cTDI with offline analysis permits rapid and accurate definition of fetal arrhythmia mechanism, providing new information in a significant proportion of affected pregnancies. (AU)

Ductus arteriosus and fetal echocardiography: Implications for practice.

The ductus arteriosus (DA) is a crucial part of the fetal circulation, both in the normal fetus and in critical congenital heart disease (CHD). It allows shunting between the pulmonary and systemic circulations. In physiological prenatal conditions, the DA lets the majority of right ventricular output bypass the fluid-filled, high-resistance lungs. The DA can cause hemodynamic compromise in the fetus and neonate when constricted or absent (in isolation or in patients with CHD) and may lead to pre- or postnatal sequelae within other systems when forming part of a vascular ring. In CHD, the DA can be interrogated by fetal echocardiography to infer information regarding severity of pulmonary outflow tract obstruction, adequacy of the sub-pulmonary ventricle to supply pulmonary blood flow, and to predict the likelihood of atrial septum restriction in transposition of the great arteries. A good understanding of the DA is crucial for fetal cardiologists.

Ductus arteriosus and fetal echocardiography: Implications for practice

The ductus arteriosus (DA) is a crucial part of the fetal circulation, both in the normal fetus and in criticalcongenital heart disease (CHD). It allows shunting between the pulmonary and systemic circulations. In physiologicalprenatal conditions, the DA lets the majority of right ventricular output bypass the fluid-filled, highresistancelungs. The DA can cause hemodynamic compromise in the fetus and neonate when constricted orabsent (in isolation or in patients with CHD) and may lead to pre- or postnatal sequelae within other systemswhen forming part of a vascular ring. In CHD, the DA can be interrogated by fetal echocardiography to inferinformation regarding severity of pulmonary outflow tract obstruction, adequacy of the sub-pulmonary ventricleto supply pulmonary blood flow, and to predict the likelihood of atrial septum restriction in transposition of thegreat arteries. A good understanding of the DA is crucial for fetal cardiologists.