Links between heat exposure and congenital anomalies have not been explored in detail despite animal data and other strands of evidence that indicate such links are likely. We reviewed articles on heat and congenital anomalies from PubMed and Web of Science, screening 14,880 titles and abstracts in duplicate for articles on environmental heat exposure during pregnancy and congenital anomalies. Thirteen studies were included. Most studies were in North America (8) or the Middle East (3). Methodological diversity was considerable, including in temperature measurement, gestational windows of exposure, and range of defects studied. Associations were detected between heat exposure and congenital cardiac anomalies in three of six studies, with point estimates highest for atrial septal defects. Two studies with null findings used self-reported temperature exposures. Hypospadias, congenital cataracts, renal agenesis/hypoplasia, spina bifida, and craniofacial defects were also linked with heat exposure. Effects generally increased with duration and intensity of heat exposure. However, some neural tube defects, gastroschisis, anopthalmia/microphthalmia and congenital hypothyroidism were less frequent at higher temperatures. While findings are heterogenous, the evidence raises important concerns about heat exposure and birth defects. Some heterogeneity may be explained by biases in reproductive epidemiology. Pooled analyses of heat impacts using registers of congenital anomalies are a high priority.

Although several National Data Registries for Congenital Heart Disease (CHD) exist, few are comprehensive and contemporary. A National Australian CHD Registry has been developed that aims to redress this by creating the first comprehensive data collection for CHD children and adults, initially across Australia. We defined and collected a minimum dataset of demographics, diagnoses, and procedures from people with CHD presenting at participating quaternary CHD services Australia-wide. Data were collected from a range of clinical data sources. Diagnoses and procedures were standardised to the European Paediatric Congenital Code – Short List. Methodological limitations were carefully documented. From 8 participating institutions, an initial 359,084 patient records were assessed for eligibility and 68,234 unique individuals with structural CHD have been included in the current dataset. There were 20,395 (30 %) people with mild CHD, 25,157 (37 %) with moderate CHD, and 13,530 (20 %) with severe CHD (6 % unknown complexity). The most common diagnoses were Ventricular Septal Defect (16,781, 25 %), Atrial Septal Defect (6,607, 10 %), Aortic Valve Disorders (5516 8 %), Coarctation of the Aorta (5,321, 8 %), Tetralogy of Fallot (4,489, 7 %), Transposition of the Great Arteries (4,009, 6 %). The data presented here represents the most comprehensive cohort collected for the Australian CHD population thus far and is comparable with the largest contemporary CHD registries around the world. This Registry represents a key resource for improved understanding of the CHD population and will drive better care and outcomes for people living with CHD.

Background: Peak oxygen consumption (peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ ) is traditionally divided (“ratio‐scaled”) by body mass (BM) for clinical interpretation. Yet, it is unknown whether ratio‐scaling to BM can produce a valid size‐independent expression of peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ in people with a Fontan circulation. Furthermore, people with a Fontan circulation have deficits in lean mass, and it is unexplored whether using different measures of body composition may improve scaling validity. The objective was to assess the validity of different scaling denominators (BM, stature, body surface area, fat‐free mass, lean mass, and appendicular lean mass using ratio and allometric scaling). Methods and Results: Eighty‐nine participants (age: 23.3±6.7 years; 53% female) with a Fontan circulation had their cardiorespiratory fitness and body composition measured by cardiopulmonary exercise testing and dual‐energy x‐ray absorptiometry. Ratio and allometric (log‐linear regression) scaling was performed and Pearson correlations assessed scaling validity. Scaling denominators BM ( r =−0.25, P =0.02), stature ( r =0.46, P <0.001), and body surface area (0.23, P =0.03) were significantly correlated with their respective ratio‐scaled expressions of peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ , but fat‐free mass, lean mass, or appendicular lean mass were not ( r ≤0.11; R ² =1%). Allometrically expressed peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ resulted in no significant correlation with any scaling denominator ( r =≤0.23; R ² =≤4%). Conclusions: The traditional and accepted method of ratio‐scaling to BM is invalid because it fails to create a size‐independent expression of peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ in people with a Fontan circulation. However, ratio‐scaling to measures of body composition (fat‐free mass, lean mass, and appendicular lean mass) and allometric techniques can produce size‐independent expressions of peak $$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$$ in people with a Fontan circulation.

Antegrade pulmonary blood flow (APBF) may be left or eliminated at the time of the superior cavopulmonary connection (SCPC). Our aim was to assess the impact of leaving native APBF at the SCPC on long-term Fontan outcomes. In the Australia and New Zealand Fontan Registry (1985-2021), 587 patients had pre-existing native APBF at the SCPC. At the SCPC, 302 patients had APBF eliminated (APBF⁻) and 285 patients had APBF maintained (APBF⁺). The incidence of Fontan failure (composite end point of Fontan takedown, transplant, plastic bronchitis, protein losing enteropathy and death) and atrioventricular (AV) valve repair/replacement post SCPC was compared between the 2 groups. Sex, predominant-ventricle morphology, isomerism, primary diagnosis, and age/type of Fontan were similar between groups. APBF⁻ versus APBF⁺ had a higher incidence of arch obstruction/coarctation (17% vs 7%) and previous pulmonary artery band (54% vs 45%) and a lower rate of Fontan fenestration (27% vs 41%). The risk of Fontan failure was similar between the 2 groups (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.58-1.78; P = .96). The risk of AV-valve repair/replacement was greater in APBF⁺ versus APBF– (HR, 2.32; CI, 1.13-4.75; P = .022). The risk of AV-valve repair/replacement remained after adjustment for arch obstruction/coarctation, previous pulmonary artery band and Fontan fenestration (HR, 2.27; CI, 1.07-4.81; P = .033). Maintaining APBF at the time of the SCPC does not impact the risk of Fontan failure but may increase the incidence of AV-valve repair and/or replacement post-SCPC.