Intracardiac leiomyomatosis is a rare complication that occurs when a uterine leiomyoma (fibroid) undergoes vascular invasion and propagates within the inferior vena cava to reach the right atrium. This article describes a case of intracardiac leiomyomatosis in a middle-aged woman, exploring the presentation, diagnosis and surgical management of this condition. In this case the presenting complaints were syncope and atrial fibrillation, illustrating the importance of performing a transthoracic echocardiogram in patients presenting with their first episode of atrial fibrillation. Clinicians should consider intracardiac leiomyomatosis when evaluating women with right heart masses, especially those with a history of uterine leiomyomas.