Background: The Fontan operation has provided life-saving palliation and adult survival for individuals born with single ventricle physiology. Many now seek advice about safe pregnancy. Little data are, however, available, consisting mainly of anecdotal experience and small series. This article seeks to review the published literature and identify lessons learnt from this collective experience. Methods and Results: We conducted a systematic review to evaluate maternal and fetal outcomes of pregnancy in women with a Fontan circulation. Among 1150 studies that were screened, 6 studies had sufficient longitudinal data points to qualify for meaningful inclusion, yielding 255 pregnancies in 133 women after Fontan procedure resulting in 115 live births (45%; including reports from 1986 to 2015). There was a total of 137 pregnancy losses (69%), with 115 miscarriages (45%), 19 elective terminations of pregnancy (7%), 2 stillbirths (1%), and 1 ectopic pregnancy (1%).The most common cardiovascular adverse events were supraventricular arrhythmia affecting 8.4% (range, 3%–37%) and heart failure affecting 3.9% (range, 3%–11%) of pregnancies. These complications were successfully managed with conventional approaches. No maternal deaths were reported. Postpartum hemorrhage was the predominant obstetric complication affecting 14% of the patients. Most patients were on antiplatelet agents (27%) or anticoagulants (50%) whereas only a minority (11%) were on neither. Among the 115 live births, 68 were premature (59%), 17 were small for gestational age (20%), and neonatal death occurred in 6 patients (5%). Conclusions: The most commonly reported cardiovascular complications in patients with Fontan physiology–associated pregnancy were arrhythmia and heart failure. Miscarriages were highly prevalent as was prematurity and intrauterine growth restriction. Postpartum hemorrhage seems to be the most common obstetric complication. Large-scale data sets are needed to confirm these early observations and address the late sequelae of pregnancy in women with a Fontan circulation.

The prevalence of germline mutations in paediatric pulmonary hypertension (PH) is poorly documented. The objective of this study was to determine the mutation frequency in PH genes in a paediatric cohort and describe the clinical characteristics of mutation carriers.The study involved 66 index cases with PH: 35 children with idiopathic pulmonary arterial hypertension (IPAH); five children with familial PAH (FPAH); three children with pulmonary veno-occlusive disease (PVOD); and 23 children with PAH associated with congenital heart disease (APAH-CHD).No mutations were found in the 23 children with APAH-CHD. In the 40 children with IPAH or FPAH, 12 mutations were found: five onBMPR2; four onACVRL1; and three onTBX4.In the three PVOD cases, two carried theEIF2AK4mutation. Mutation carriers had a more severe disease at diagnosis and more aggressive first-line therapy was required. The three patients with PVOD had a very severe disease at diagnosis and required a lung transplantation.The genetic architecture of paediatric PAH is enriched inACVRL1andTBX4mutations compared to adult PAH, but further studies are required to confirm these results. Childhood-onset PAH in children carrying a mutation in one of the genes tested has a more severe presentation at diagnosis but a similar outcome to that observed in non-carriers.

Sudden cardiac death (SCD) accounts for up to 25% of deaths in patients with congenital heart disease (CHD). To date, research has largely been driven by observational studies and real-world experience. Drawbacks include varying definitions, incomplete taxonomy that considers SCD as a unitary diagnosis as opposed to a terminal event with diverse causes, inconsistent outcome ascertainment, and limited data granularity. Notwithstanding these constraints, identified higher-risk substrates include tetralogy of Fallot, transposition of the great arteries, cyanotic heart disease, Ebstein anomaly, and Fontan circulation. Without autopsies, it is often impossible to distinguish SCD from non-cardiac sudden deaths. Asystole and pulseless electrical activity account for a high proportion of SCDs, particularly in patients with heart failure. High-quality cardiopulmonary resuscitation is essential to improve outcomes. Pulmonary hypertension and CHD complexity are associated with lower likelihood of successful resuscitation. Risk stratification for primary prevention implantable cardioverter-defibrillators (ICDs) should consider the probability of SCD due to a shockable rhythm, competing causes of mortality, complications of ICD therapy, and associated costs. Risk scores to better estimate probabilities of SCD and CHD-specific guidelines and consensus-based recommendations have been proposed. The subcutaneous ICD has emerged as an attractive alternative to transvenous systems in those with vascular access limitations, prior device infections, intra-cardiac shunts, or a Fontan circulation. Further improving SCD-related outcomes will require a multidimensional approach to research that addresses disease processes and triggers, taxonomy to better reflect underlying pathophysiology, high-risk features, early warning signs, access to high-quality cardiopulmonary resuscitation and specialized care, and preventive therapies tailored to underlying mechanisms.