Stem Cell Models for Elucidating Cellular Mechanisms of Substance Use Disorders and Advancing Addiction Pharmacology.

The prevalence of adult congenital heart disease (ACHD) has risen significantly over recent decades. Currently, more than 90% of children born with congenital heart disease (CHD) survive into adulthood []. The spectrum of ACHD includes patients who underwent repair during childhood, as well as those who remain unrepaired or undiagnosed until adulthood. Mild CHD remains the most frequent, accounting for 52.7% of cases in our population, while moderate and severe forms represent 32.1% and 15.1%, respectively []. Ebstein's anomaly is among the most common congenital heart defects in our region, ranking fifth in prevalence []. Its clinical presentation varies widely, ranging from asymptomatic adults diagnosed incidentally to patients with cyanosis and heart failure []. Delayed diagnosis has a direct impact on prognosis. Disease progression can be highly variable—some patients with severe atrialization or Carpentier type C anatomy remain stable for decades and require no intervention until mid‐life, whereas others experience rapid deterioration, suggesting an underlying right ventricular myopathy []. Disease deterioration and progression are in most cases driven by arrhythmias, fibrosis, and heart failure. Determining the optimal timing for repair is challenging in our population because many patients are diagnosed at advanced stages of the disease and do not receive adequate follow‐up due to the lack of specialized centers. The mortality of repair surgery has been reported to be as high as 4% with appropriate patient selection []. Patients with advanced ACHD frequently develop refractory heart failure, prompting evaluation for heart transplantation (HT). In many cases, progression to end‐stage disease is not driven solely by ventricular dysfunction but also by systemic and venocapillary congestion, hypoxemia, multi‐organ dysfunction, arrhythmias, and reduced exercise capacity []. For patients who are unsuitable for surgical repair or palliation, transplantation may become the only viable therapeutic option. It is recommended that patients who are under consideration for HT should be assessed in a center that specializes in both HT and ACHD [].