Abstract
BACKGROUND: Cardiac masses are rare in pediatric patients, and multimodality imaging is crucial for diagnosis. These masses can present with different arrhythmias, adding challenges to their management. CASE SUMMARY: We report an unusual presentation of cardiac masses in an infant with aborted sudden cardiac arrest, ST-segment elevation electrocardiography, and recurrent supraventricular tachycardia. The masses were distant from the sinoatrial node, yet we detected severe sinus node dysfunction requiring epicardial pacemaker implantation. Although the imaging suggested malignant features, tissue biopsy confirmed the diagnosis of benign rhabdomyoma. No other manifestations of tuberous sclerosis were detected. DISCUSSION: Several cases of this tumor were reported to present with arrhythmias. The management of these cases requires a multidisciplinary approach individualized for each patient. TAKE-HOME MESSAGES: Infants with cardiac rhabdomyoma can experience severe sinus node dysfunction, irrespective of mass location, requiring pacing. Despite current advances in cardiac imaging, tissue biopsy is still the gold standard for accurate diagnosis.