Atrial FIbrillation Treatment With Cryoballoon in Heart failurE (AFICHE)

Inclusion criteria: * A minimum of at least two separate AF episodes recorded within the last 12 months, either on 12-lead rest ECG or on ambulatory ECG recordings (at least 5 minutes of AF on Holter recordings will be required), * LVEF \<40% on sinus rhythm, * symptoms consistent with heart failure (New York Heart Association II or higher) despite rate control treatment, * age \>21 years old. Exclusion criteria: * previous left atrial ablation, * left atrial diameter \>28 mm/m2 BSA on TTE (parasternal long axis view), * strong clinical suspicion that reduced LVEF is primarily due to tachycardiomyopathy, * pre-existing device (ICD or CRT) without AF detection algorithms and/or (for CRT devices) diagnostics of effective biventricular pacing, * known primary electrical heart disease (e.g. Brugada syndrome), * presence of thrombus in a heart chamber, * presence of prosthetic valve at any position, * moderate/severe valvular heart disease, * active infectious disease or malignancy, * moderate or severe hepatic impairment (Child-Pugh class B or C), * severe renal failure (estimated glomerular filtration rate \<20 ml/min/1.73 m2), * inability or unwillingness to adhere to standard treatment or to provide consent.