Do Cancer Patients Present a Different Phenotype of Atrial Fibrillation or a Different Arrhythmia Management?

<b>Background/Objectives</b>: Along with cardiovascular disease, cancer is the leading cause of death worldwide. The aim of the study was to compare the clinical and echocardiographic characteristics of atrial fibrillation (AF) among patients with active cancer (study group) and those without cancer (control group). <b>Methods</b>: This retrospective study included patients diagnosed with both AF and active cancer referred for consultation to the Cardiac Arrhythmias Outpatient Clinic at our institution in 2022. They were matched in a 1:1 ratio, by age and sex to patients with AF without cancer. The matching criteria for the study and control groups were limited to age and gender. Variables such as comorbidities, atrial fibrillation duration, tumor stage, and treatment were not included in the matching criteria. <b>Results</b>: We examined 216 patients, 57.4% of whom were men. There were 110 patients in the study group with a mean age of 70 (10) years. Several parameters in the study group attracted our particular attention: N-terminal pro-B-type natriuretic peptide (NT-proBNP) was lower (703 pg/mL vs. 1549 pg/mL, <i>p</i> = 0.01), echocardiography revealed smaller left atrial size (43 (6) mm vs. 47 (7) mm, <i>p</i> = 0.015), left ventricular (LV) diastolic dimension (49 mm vs. 52 mm, <i>p</i> = 0.009) and better LV systolic function expressed as LV ejection fraction (54% (9%) vs. 51% (12%), <i>p</i> = 0.025), and global longitudinal strain (-16% (4%) vs. -13% (3%), <i>p</i> = 0.016). Antiarrhythmic pharmacotherapy was used less frequently in the study group, which may also have been due to physicians' reluctance to treat AF aggressively in a more morbid population. <b>Conclusions</b>: Patients with cancer and atrial fibrillation may have a different clinical profile, suggesting a different pathophysiology. Understanding these differences may help reduce the incidence of AF and improve patient outcomes and prognosis during cancer treatment.