EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Prenatal diagnosis of congenital heart disease

Cardiac Axis in Early Gestation and Congenital Heart Disease

Congenital heart defects represent the most common structural anomalies observed in the fetal population, and they are often associated with significant morbidity and mortality. The fetal cardiac axis, which indicates the orientation of the heart in relation to the chest wall, is formed by the angle between the anteroposterior axis of the chest and the interventricular septum of the heart. Studies conducted during the first trimester have demonstrated promising outcomes with respect to the applicability of cardiac axis measurement in fetuses with congenital heart defects as well as fetuses with extracardiac and chromosomal anomalies, which may result in improved health outcomes and reduced healthcare costs. The main aim of this review article was to highlight the cardiac axis as a reliable and powerful marker for the detection of congenital heart defects during early gestation, including defects that would otherwise remain undetectable through the conventional four-chamber view.

Developmental Aspects of Cardiac Adaptation to Increased Workload

The heart is capable of extensive adaptive growth in response to the demands of the body. When the heart is confronted with an increased workload over a prolonged period, it tends to cope with the situation by increasing its muscle mass. The adaptive growth response of the cardiac muscle changes significantly during phylogenetic and ontogenetic development. Cold-blooded animals maintain the ability for cardiomyocyte proliferation even in adults. On the other hand, the extent of proliferation during ontogenetic development in warm-blooded species shows significant temporal limitations: whereas fetal and neonatal cardiac myocytes express proliferative potential (hyperplasia), after birth proliferation declines and the heart grows almost exclusively by hypertrophy. It is, therefore, understandable that the regulation of the cardiac growth response to the increased workload also differs significantly during development. The pressure overload (aortic constriction) induced in animals before the switch from hyperplastic to hypertrophic growth leads to a specific type of left ventricular hypertrophy which, in contrast with the same stimulus applied in adulthood, is characterized by hyperplasia of cardiomyocytes, capillary angiogenesis and biogenesis of collagenous structures, proportional to the growth of myocytes. These studies suggest that timing may be of crucial importance in neonatal cardiac interventions in humans: early definitive repairs of selected congenital heart disease may be more beneficial for the long-term results of surgical treatment.

New born pulse oximetry screening: A global perspective

The possibility of pulse oximetry screening (POS) for congenital heart defects was first described over 20 years ago. Since then, an accumulation of research evidence and clinical practice experience has established POS as an important test to detect critical congenital heart defects (CCHDs). POS meets the criteria for universal screening and professional bodies around the globe have recommended universal POS. Many countries have already adopted POS while several others are working towards its implementation. In low and low-middle-income countries (LLMIC), POS has the additional potential for reducing morbidity and mortality from neonatal sepsis. This review summarises the evidence for POS and looks at current global uptake and different approaches to the implementation of POS.

Congenitally Malformed Hearts: Aspects of Teaching and Research Involving Medical Students

To appreciate congenital heart disease fully, a detailed understanding of the anatomical presentation, as well as the physiology, is required. This is often introduced at an advanced stage of training. Professor Anderson has been influential in the Clinical Anatomy Intercalated BSc programme at the University of Birmingham, in particular in his teaching on Sequential Segmental Analysis. This article describes the experiences of the latest cohort of students on this programme, who undertook varying research projects using the Birmingham Cardiac Archive, with the guidance of Professor Anderson. The projects outlined include various aspects of isomerism, encompassing both the cardiac and abdominal manifestations, as well as details of congenitally corrected transposition of the great arteries and prenatally diagnosed right aortic arch and double arch. These studies all aimed to increase the knowledge base of their respective cardiac malformations and provide a basis for further research.

First-Trimester Diagnosis of Hypoplastic Left Heart Syndrome: A Case Report

Hypoplastic left heart syndrome (HLHS) comprises a spectrum of left-sided heart anomalies resulting from left outflow or inflow obstruction. Obstruction most often occurs at the levels of the aortic valve and/or mitral valve due to stenosis or atresia. HLHS is a lethal cardiac anomaly if not treated within the first week of life. Knowledge of sonographic features could aid in early detection, which results in better planning and management of pregnancy. This report presents a case in which HLHS was discovered during a routine dating and viability sonogram, performed at 12 weeks’ gestation.

Fetal heart examination at the time of 13 weeks scan: a 5 years' prospective study

Objective To evaluate our ability in classifying the fetal heart as normal or abnormal during the 1st trimester scan through fetal cardiac examination and determining the best time for this examination. Methods This was a prospective study performed on 3240 pregnant women to examine the fetal heart. Four chambers view and ventricular outflow tracts were mainly examined during the scan. We used grayscale and color mapping in the diagnosis. Color Doppler was used if additional information was needed, and all patients were rescanned during the 2nd trimester to confirm or negate our diagnosis. Results The cardiac findings were normal at both scans in 3108 pregnancies. The same cardiac abnormality was detected at both scans in 79 cases. In 36 cases there was false-positive diagnosis at the early scan; in 20 of these cases, there were mildly abnormal functional findings early in pregnancy with no abnormality found later. In 17 fetuses, there was discordance between the early and later diagnosis due to missed or incorrect diagnoses. The best time to do fetal heart examination during 1st trimester is between 13 and 13 + 6 weeks. Conclusion A high degree of accuracy in the identification of congenital heart disease (CHD) can be achieved by a 1st trimester fetal echocardiography.

The role of cardiac surgeons in online prenatal counselling for congenital heart disease

Objective

To explore the role of cardiac surgeons in prenatal online counselling for congenital heart disease.

Methods

From January 2014 to December 2017, the author consulted on 400 cases of foetal cardiovascular abnormalities through the Good Doctor Online and WeChat online platforms. The author made appropriate pregnancy recommendations to patients and families using patient ultrasound reports and medical histories. Followed-up patients who chose to continue their pregnancy received postnatal advice.

Results

There were 248 simple cardiac abnormalities and 152 complex cardiac abnormalities. Foetal chromosome examination detected 2 cases of trisomy 21 syndrome and 26 normal cases. Two mothers (0.8%) of simple cardiac abnormality foetuses and 103 (67.8%) mothers of complex cardiac abnormality foetuses chose induced abortion. A total of 246 mothers of simple cardiac abnormality foetuses chose to continue pregnancy and had good postnatal prognosis. Twenty-six mothers of complex cardiac abnormality foetuses chose to continue pregnancy; among these, there were 4 intrauterine deaths, 22 births, 4 deaths while awaiting surgery and 18 successful surgeries.

Conclusion

The Good Doctor Online and WeChat platforms facilitate communication with a wide audience. Cardiac surgeons can reduce the birth incidence and improve prenatal consultations for severe congenital heart disease through these platforms.