SUMMARY
Patients with heart failure (HF) often develop ventricular and supraventricular arrhythmias, due in large part to electrical conduction abnormalities of the heart in this syndrome. Cardiac remodeling and neurohumoral activation typical of HF create a substrate that increases the risk of developing arrhythmias and/or worsening pre- existing arrhythmias. Advances in our understanding of the underlying pathophysiological mechanisms of HF have reinforced the importance of neurohumoral, mechanical and inflammatory processes as progressively more severe pump dysfunction occurs. This combination increases the likelihood of arrhythmias, both atrial and ventricular, such that ventricular arrhythmias are found in up to 80% of patients with severe HF, conferring additional risk of mortality and morbidity, in particular via an increased risk of sudden cardiac death. Arrhythmias are also responsible for an increased risk of rehospitalisation in one-third of HF patients. The high risk of arrhythmias should always be considered during the clinical management of all HF patients, due their association with worse prognosis and increased mortality. In particular, HF and atrial fibrillation mutually worsen the impact of each other. Treatment of atrial fibrillation in the setting of HF includes a variety of approaches such as drugs, devices and ablation. Restoration of sinus rhythm is not superior to optimal rate control, and the deleterious effects of antiarrhythmic drugs should be considered. Finally, cardiac function, symptoms, and quality of life may improve with catheter-based ablative therapies in appropriately selected patients with HF.