Predictors of atrial fibrillation in ibrutinib-treated CLL patients: a prospective study

Background: Ibrutinib is an oral irreversible inhibitor of Bruton's tyrosine kinase, indicated for the treatment of chronic lymphocytic leukaemia. The drug is generally well tolerated; however, not infrequent side effects are reported, with the major two being bleeding and ibrutinib-related atrial fibrillation. Atrial fibrillation pathogenesis in this setting is not completely clear, and no prospective studies have evaluated the impact of previous cardiologic history and baseline characteristics. Methods: We prospectively performed cardiologic assessment in 43 CLL patients before starting ibrutinib therapy. Cardiologic workup included comorbidity collection and electrocardiographic and echocardiographic baseline evaluation. Results: After a median observation of 8 months, seven patients developed atrial fibrillation (16.3%). Cases developing atrial fibrillation were all elderly males (p = 0.04), and mostly with a history of previous arterial hypertension (p = 0.009). Atrial fibrillation occurrence also correlated with the presence of one or more pre-existent cardiologic comorbidities (p = 0.03), with a higher atrial fibrillation risk score (calculated with comorbidities and cardiologic risk factor evaluation p < 0.001), and with higher left atrial diameter (p = 0.02) and area (p = 0.03) by echocardiography. The occurrence of atrial fibrillation was managed after an integrated cardio-oncologic evaluation: anticoagulation was started in 4 (57.1%) patients and beta-blockers or amiodarone in 5 (71.4%). One patient underwent electric cardioversion and another patient pacemaker positioning to normalise heart rate in order to continue ibrutinib. Conclusion: Our data show that echocardiography is a highly informative and reproducible tool that should be included in pre-treatment workup for patients who are candidates for ibrutinib therapy.