Atrial septal defects (ASDs) represent the most common congenital heart defect diagnosed in adulthood. Although considered a simple defect, challenges in optimal diagnostic and treatment options still exist due to great heterogeneity in terms of anatomy and time-related complications primarily arrhythmias, thromboembolism, right heart failure and, in a subset of patients, pulmonary arterial hypertension (PAH). Atrial septal defects call for tertiary expertise where all options may be considered, namely catheter vs. surgical closure, consideration of pre-closure ablation for patients with atrial tachycardia and suitability for closure or/and targeted therapy for patients with PAH. This review serves to update the clinician on the latest evidence, the nuances of optimal diagnostics, treatment options, and long-term follow-up care for patients with an ASD.

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.

Rates of successful surgical repair and life expectancy for patients with congenital heart disease have increased dramatically in recent decades. Thanks to advances in diagnosis, treatment, and follow-up care, an ever-increasing number of individuals with congenital heart disease are reaching advanced age. The exposure to cardiovascular risk factors during their lifetime is modifying the outlook and late clinical trajectory of adult congenital heart disease (ACHD). Their disease burden is shifting from congenital to acquired, primarily atherosclerotic cardiovascular disease (ASCVD) with worrisome consequences. In addition, the complex background of ACHD often curbs appropriate preventive strategies by general practitioners or adult cardiologists. Comprehensive guidance for the prevention and management of acquired heart disease in ACHD patients is currently not available, as this topic has not been covered by the European Society of Cardiology (ESC) guidelines on cardiovascular disease prevention or the ESC guidelines for the management of ACHD. In this document, a state-of-the-art overview of acquired heart disease in ACHD patients and guidance on ASCVD prevention for both ACHD specialists and non-ACHD cardiologists are provided. The aim is to provide a clinical consensus statement to foster the development of a sustainable strategy for the prevention of ASCVD in a practical and simple-to-follow way in this ever-growing cardiovascular cohort, thus reducing their cardiovascular burden.