Arrhythmic risk during pregnancy in patients with congenital heart disease

Arrhythmias play a significant role in the morbidity and mortality of patients with adult congenital heart disease (CHD). Pregnancy-associated physiological changes in hormonal status, hemodynamics, and myocardial structure further enhance arrhythmic risk in CHD patients, leading to increased adverse maternal and foetal events and making arrhythmias one of the most common complications during pregnancy. Nearly all CHD patients are affected by asymptomatic rhythm disturbances during the ante-, peri-, or post-partum periods, and almost one tenth of patients develop sustained, symptomatic arrhythmias requiring treatment. The majority of arrhythmias originate from the atrium, mostly in the form of supraventricular tachycardia or atrial fibrillation. Patients with CHD often tolerate these even more poorly during pregnancy than before pregnancy. Sustained ventricular tachycardia or ventricular fibrillation are rare, but potentially life-threatening for mother and foetus. Risk stratification models developed specifically for arrhythmias during pregnancy in CHD patients are lacking, but direct or indirect signs of heart failure, previous history of arrhythmia, and complex CHD may be associated with higher arrhythmic risk in these patients. Rigorous individual assessment before, and careful monitoring during pregnancy in a multidisciplinary team is crucial to ensure the best possible pregnancy outcome for patients with CHD.