Transthoracic Echocardiography as a Tool for Early Detection of Atrial Fibrillation in Patients Receiving Ibrutinib

<b>Background</b>: Bruton's tyrosine kinase inhibitors, particularly ibrutinib, have improved outcomes in patients with chronic lymphocytic leukemia but are associated with an increased risk of atrial fibrillation. The early identification of patients with increased susceptibility to atrial fibrillation remains a major challenge in cardio-oncology. <b>Methods</b>: This prospective pilot study included 45 patients with chronic lymphocytic leukemia treated with ibrutinib. All patients underwent comprehensive transthoracic echocardiography at baseline and after 6 months. Left atrial structure and function were assessed, with particular emphasis on speckle-tracking-derived left atrial strain parameters, including peak atrial longitudinal strain and peak atrial contraction strain. <b>Results</b>: At follow-up, a modest but significant increase in indexed left atrial volume was observed, while left atrial functional parameters remained stable. Patients who developed atrial fibrillation showed significantly lower baseline Peak Atrial Contraction Strain values compared with those who remained in sinus rhythm, whereas no significant differences in Peak Atrial Longitudinal Strain were detected. <b>Conclusions</b>: Ibrutinib-related atrial fibrillation appears to be driven primarily by pre-existing atrial vulnerability rather than early drug-induced atrial dysfunction. The baseline impairment of left atrial contractile function may represent a candidate echocardiographic marker of atrial functional vulnerability and may inform cardiovascular surveillance and monitoring strategies in patients treated with ibrutinib.