Epidemiology, symptomatology, diagnosis and clinical implications of cystic tumors of atrioventricular node (CTAVN): A systematic review.
Authors: Jaiswal Vikash , Batra Nitya , Khosla Atulya Aman , Mashkoor Yusra , Vadhera Ananya , Shrestha Abhigan Babu , Deb Novonil , Chisti Mohammad Muhsin 
Published: June 2024

e23561 Background: Primary cardiac tumors have an incidence of 0.0017% to 0.03% of all autopsies. CTAVN is a rare tumor associated with sudden cardiac death, and its incidence cannot be accurately determined as the diagnosis has been historically made on incidental or intentional autopsy with careful microscopic examination of the conduction system. To date, no systematic evaluation has been made of its clinical outcomes and diagnosis methods; hence, we sought to perform a systematic analysis based on available literature. Methods: A systematic literature search was performed on PubMed, Embase, Cochrane, and Scopus. Studies with a confirmed pathological diagnosis of CTAVN were included. All statistical analyses were conducted on R version 4.1.2. Results: 34 studies with 42 patients with a diagnosis of CTAVN were included. A significant majority of patients were female (n = 29,69%), mean age (±SD) of patients was 47.7 ± 9.33 years. Dyspnea was the most commonly reported symptom among 12 patients (28.5%), followed by palpitations (10,23.8%), syncope (6,14.2%), chest pain (6, 14.2%), dizziness (4,9.5%) and, fatigue (3,7.1%). Third-degree AV block was the most common EKG finding (11,26.1%), followed by first-degree (8, 19.0%) and ventricular fibrillation (n = 2, 4.6%). Transthoracic, transesophageal echo, and cardiac MRIs were done in the majority of the patients. The tumors were most commonly located in the lower part of the interatrial septum in 33% (14), AV node (13, 30.9%), followed by tumors involving both AVN and proximal His bundle/interventricular septum (7, 16.67%). Histopathologically, multiple different lining epithelia were reported: cuboidal cell lining (18, 42.8%), squamous lining (6, 14.2%) and transitional lining (7, 16.6%), most of the tumors (n = 15, 30.9%) were endodermal in origin. Immunohistochemically, 38% of patients had positive epithelial membrane antigen. 45.2% of patients were positive for carcinoembryonic antigen. Cytokeratin was positive in 47.6% of the tumors. Due to varying degrees of AV block, a significant number of patients required pacemaker implantation (13, 30.9%), and 1 patient required intracardiac defibrillator placement. In 9 patients (21.4%), the AV nodal cystic tumor was surgically removed. 21/42 patients were alive; mortality due to CTAVN was reported in 10(23.8) percent of patients. Causes of mortality included cardiac complications (8,19%), respiratory complications (5,11.9%), central nervous system complications (2, 4.7%), sepsis (2,4.7%), and surgical complication (1, 2.3%) Conclusions: To our knowledge, this is the first and largest review on CTAVN. This review contributes valuable insights into the diagnosis, histopathology, and management of cystic tumors of the AV node, offering a foundation for further research on workup, clinical considerations, and treatment of this rare cardiac pathology.