[Arrhythmia in adults with congenital heart defects : Incidence, substrates, and mechanisms].

Arrhythmia management is one of the main challenges in the treatment of adult patients with congenital heart disease (ACHD). Apart from heart failure, arrhythmias are mainly responsible for morbidity and mortality in these patients. Supraventricular tachycardia is more frequent than ventricular arrhythmias and is not only associated with debilitating symptoms, but is often as threatening as ventricular tachycardia. The incidence depends on the underlying defect, type, and time of repair. For the overall ACHD population the incidence of supraventricular tachycardia is up to 50 % and increases with age and time since surgery. Arrhythmia substrate relates to structural abnormalities due to the congenital defect and most importantly to the amount of incisions and material used for repair. In addition, poor hemodynamic conditions influence substrate through dilatation, hypertrophy, and fibrosis. Both supraventricular and ventricular arrhythmias are due to a macroreentrant mechanism in the vast majority of patients, but focal arrhythmias occasionally occur as well.