Supplementary Material for: Cardiac Arrhythmias Associated with Brain Tumors: A Systematic Review

Introduction: Brain tumors may disrupt cardiac autonomic regulation, leading to arrhythmias that complicate patient management. This review aims to synthesize evidence on the relationship between brain tumor characteristics, treatments, and cardiac arrhythmias. Methods: A systematic literature search was performed with independent screening and data extraction by two reviewers. Due to heterogeneity in study designs, tumor types, and arrhythmia outcomes, quantitative meta-analysis was not feasible; results were synthesized qualitatively. Results: Supratentorial tumors, especially in limbic and insular regions, were frequently associated with atrial arrhythmias and ECG abnormalities. High-grade tumors showed diverse arrhythmias, including bradycardia and ventricular events, often linked to tumor progression or seizures. Surgical resection improved arrhythmias but posed perioperative risks, notably with right insular involvement. Chemotherapy effects were variable; radiation-induced arrhythmias were infrequent and dose-dependent. Arrhythmia patterns varied across pre-, peri-, and post-treatment phases, reflecting complex neurocardiac interactions. Conclusion: Cardiac arrhythmias in brain tumor patients arise from multifactorial mechanisms influenced by tumor biology and treatment effects. Prospective, standardized studies are required to clarify underlying mechanisms and optimize arrhythmia management in neuro-oncology.