Atrial fibrillation in CLL patients treated with ibrutinib. An international retrospective study

Summary Atrial fibrillation (AF) occurs in 5–9% of patients treated with ibrutinib for chronic lymphocytic leukaemia (CLL); the clinical consequences and optimal management are unclear. We retrospectively studied 56 CLL patients who received ibrutinib and developed AF. Median time to onset was 3·8 months. AF was persistent in 35/56 (62%) cases despite treatment. Clinical consequences included: three episodes of severe cardiac failure (one fatal) and one stroke; eight non‐thrombocytopenic patients (14%) experienced severe bleeding adverse events. Altogether, ibrutinib was permanently discontinued in 26/56 cases (46%). Data to guide optimal management are lacking and clinical practice guidelines are urgently needed.