Ventricular arrhythmias in congenital heart disease: how can the electrophysiologist help?

Arrhythmias are the most common reason for hospital visits for grown-up congenital heart disease (GUCH) patients [1]. For these vulnerable patients, arrhythmias can be a sign of haemodynamic decompensation, or can themselves result in rapid decompensation. Arrhythmias that are relatively innocuous in other patients can be severely compromising in the GUCH population, whose cardiovascular haemodynamics are often precariously balanced. CARDIOVASCULAR MEDICINE -KARDIOVASKULRE MEDIZIN -MDECINE CARDIOVASCULAIRE 2017;20(2):27-35 Summary Patients with congenital heart disease often have ventricular hypertrophy, dilatation and/or fibrosis as part or a direct consequence of their malformation. Moreover, they often have ventricular scars and/or patches and develop secondary haemodynamic overload or valvular abnormalities as a consequence of reparative surgery/interventions that worsen ventricular remodelling. This ventricular remodelling predisposes to polymorphic ventricular tachycardia (VT) or ventricular fibrillation (VF) and sudden cardiac death, as in other forms of heart disease. The presence of an extensive ventricular scar/patch leads to the occurrence of rapid and often poorly tolerated sustained monomorphic reentrant VT, resulting in haemodynamic collapse and even sudden cardiac death. Acute therapy of VT/VF is applicable in accordance with standard guidelines. Chronic management includes reparative therapy of the underlying congenital heart malformation and heart failure treatment, but specific arrhythmia management should ideally be provided by a qualified electrophysiologist who can precisely diagnose the arrhythmia and its mechanism, provide prognostic stratification, determine the substrate, administer specialised electrical therapies including antitachycardia pacing and automatic internal cardiac defibrillation from an implanted device, or perform catheter ablation of the VT substrate. Finally, electrophysiological evaluation can provide valuable information to guide the surgeon to incorporate arrhythmia-neutralising incisions into reparative surgery.