It is well known that both atrial and ventricular arrhythmias play a key role in morbidity and overall mortality among patients with heart failure. In addition to pharmacological treatment, up-to-date and evidence-based use of invasive electrophysiology, including implantable cardioverter defibrillator implantation, is recommended in the global management of patients with heart failure. This article will review current clinical indications for invasive electrophysiology, either acknowledged or under evaluation, focusing on the scientific background and some technical and practical aspects. The discussion is organized in an arrhythmia-based manner so that ventricular-, atrial-, and heart transplant-related arrhythmias will be discussed separately.