Abstract Body (Do not enter title and authors here): Background: Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease characterized by the formation of benign tumors located mainly in the central nervous system, skin, kidneys, heart, eyes and lungs . It is estimated that 70% to 90% of rhabdomyomas (the most prevalent cardiac tumors in the pediatric population) are related to TSC. Most cardiac tumors regress spontaneously during the first year of life. However, there are reports of recurrence, suggesting the possibility of hormonal influence.

Purpose: To perform a descriptive study of clinical variables, with a cardiological focus, electrocardiographic, echocardiographic and cardiac magnetic resonance imaging characteristics, in addition to the treatment and clinical evolution of patients diagnosed with TSC treated over 24 years of follow-up.
Methods: A retrospective, descriptive study will be carried out at the Clinical Unit of Cardiomyopathies and Congenital Heart Diseases of InCor/FMUSP. Data was collected from the institution's electronic medical record from January 1997 to January 2021. Patients with a clinical and or genetic diagnosis of TSC were selected. Analysis of clinical, electrocardiographic, echocardiographic and CMR variables were performed. Death and the need for surgical treatment will also be evaluated. Data from the first and last TTE and CMR available in the system were analyzed.
Results: 77 patients with TSC diagnosis were included, 47 (61%) patients were females. The mean age of the patients was 24 ± 15.1 years. The majority of patients (N = 67; 87%) self-reported white ethnicity. 50 patients had cardiac tumors, 49 patients had rhabdomyomas (RM) and 1 patient presented with pericardial lipoma. Between the patients with RM, 15 (30%) had single tumors and 35 (70%) patients had two or more tumors. Regarding clinical evolution, 39 patients (78%) presented incomplete involution, 9 patients (18%) complete regression and 1 patient presented an increase in the mass. Surgical treatment was necessary, at some point, in 4 (8%) patients and 2 (4%) patients died during the postoperative period. There is no record of heart transplantation.
Conclusions: Regarding clinical variables, 64% of the patients had cardiac tumors. Most patients were asymptomatic, only (4%) had complex ventricular arrhythmias. Most patients had multiple LV or biventricular rhabdomyomas assessed by TTE or CMR. The majority of patients (78%) had incomplete involution of rhabdomyomas in 24 years of follow-up.