CONGRESS ABSTRACT

Introduction Repaired Tetralogy of Fallot (ToF) exposes pregnant women to significant cardiovascular risks, including Major Adverse Cardiac Events (MACE: clinically relevant arrhythmia or heart failure), often due to residual lesions such as pulmonary regurgitation. This study evaluates maternal and perinatal outcomes in a high-risk ToF cohort, analyzing the impact of a specialized management protocol. Methods A retrospective, single-center study was conducted at the Adult Congenital Heart Disease (ACHD) Center of Monaldi Hospital in Naples. Between 2000 and 2025, 75 pregnancies were recorded in ToF women and included in the study. The primary endpoint was the incidence of MACE. All patients received intensive outpatient monitoring, with a minimum of two follow-up during gestation, and pre-existing antiarrhythmic therapy was maintained when necessary. Results The mean maternal age was 30.3±5.8 years. The cohort presented a high-risk profile: Severe Pulmonary Regurgitation: 27 cases (36%). History of Arrhythmia: 15 cases (20%). Unoperated ToF (natural history): 3 cases (4%). Continuous Antiarrhythmic Therapy: 7 patients (9.3%) remained on therapy (5 on beta-blockers, 1 on digoxin, 1 on beta-blockers + digoxin). Maternal outcome: A total of four MACE (5.3%) were observed, all manifesting as clinically relevant arrhythmias; no heart failure events were recorded. Univariate analysis suggested a significant association between the occurrence of MACE (arrhythmias) and history of arrhythmia (p=0.02), reduced TAPSE (p<0.01), and reduced LVEF (p<0.01). Perinatal outcomes: Two perinatal deaths (2.6%) were recorded: one fetal demise (placental abruption) and one neonatal death (renal malformations). Conclusions Our data demonstrate that, within a specialized ACHD management protocol, the risk of major maternal cardiac complications can be effectively mitigated, even in the presence of established high-risk factors. The absence of heart failure events confirms the protective efficacy of an intensive outpatient monitoring. However, the persistent presence of arrhythmic events underscores the critical need for comprehensive arrhythmic risk stratification to optimize outcomes. The significant perinatal risk underscores the critical importance of integrated obstetrics-cardiology care.