Atrial fibrillation in hematologic malignancies: A systematic review and meta-analysis.

e24018 Background: Atrial fibrillation (AF) affects approximately 1-2% of the general adult population, with incidence rates around 5-7 per 1,000 person-years, and sharp increases in advanced age. Among patients with cancer, AF is increasingly recognized and may be particularly prevalent in those with hematologic malignancies due to systemic inflammation, shared cardiovascular risk factors, and exposure to potentially arrhythmogenic therapies. In this population, AF further complicates management given competing risks of thrombosis and bleeding, yet the burden of AF has not been systematically quantified. Methods: We conducted a systematic review and meta-analysis of observational studies reporting the incidence and/or prevalence of AF among adults with hematologic malignancies. PubMed and Embase were searched from database inception through January 24, 2026, in accordance with PRISMA guidelines. Eligible studies included cohort, registry-based, or population-based designs reporting AF incidence or prevalence. Studies limited to peri-operative or post-procedural AF, pediatric populations, or AF reported solely as an adverse effect of a specific anticancer therapy were excluded. Random-effects models were used to pool prevalence and incidence estimates. Subgroup analyses and meta-regression were performed to explore sources of heterogeneity. Results: Twelve studies involving 949,304 patients were included in the prevalence analysis, yielding a pooled AF prevalence of 10.6% (95% CI, 7.6-14.6; I² = 99.9%), substantially higher than estimates reported in the general population. Prevalence was highest among patients with lymphoma (17.1%) and chronic lymphocytic leukemia (16.6%). Seven studies reporting 4,764 AF events over 299,818 person-years were included in the incidence analysis, resulting in a pooled incidence rate of 12.18 per 1,000 person-years (95% CI, 8.35-16.00; I² = 99.2%). The highest incidence rates were observed in lymphoma and multiple myeloma. Meta-regression identified older age, male sex, and geographic region as significant contributors to heterogeneity. Conclusions: AF is frequent among patients with hematologic malignancies, with incidence and prevalence markedly higher than in the general population and substantial variation across disease subtypes. These findings underscore the significant cardio-oncology burden of AF in this high-risk group and highlight the need for improved risk stratification, surveillance strategies, and prospective studies to inform optimal management.