A third selective BTK inhibitor, zanubrutinib (BGB-3111), has also shown preserved efficacy in CLL (ORR/CRR 97%/14%), with infrequent major bleeding and atrial fibrillation (2%-3% of patients after a median follow up of 27 months) and more patients ceasing due to progressive disease than adverse effects (11% vs. 3%)[139,155]. This evidence concerns the gene BTK and atrial fibrillation.