Beat To Beat: Antenatal Fetal Arrhythmia To Newborn Ventricular Tachycardia Caused By Rhabdomyomas and a Subsequent Diagnosis Of Tuberous Sclerosis

Background: The findings of an irregular fetal heart rate antenatally and subsequently rhabdomyomas in the fetus suggest a genetic disease of considerable importance. Multiple rhabdomyomas trigger suspicion of tuberous sclerosis complex (TSC) as it is present in more than 80% of cases of rhabdomyomas. Usually, rhabdomyomas regress without intervention but the association with TSC is life changing for the family. Knowledge of the outcome of affected fetuses and the true incidence of TSC in fetal cardiac rhabdomyomas is critical for accurate prenatal counseling and planning of prenatal treatment as well as infant care after delivery.

Case: The case report discusses a patient with an irregular fetal heart rate detected at 34 weeks gestation. Ultrasound revealed a slightly irregular fetal heart and a somewhat thickened cardiac septum. Ultrasound at a  level three perinatal center revealed probable rhabdomyomas of the heart and rule out tuberous sclerosis (TS). The fetal echocardiogram demonstrated intracardial rhabdomyomas with compromised outflow. Consults with a geneticist and pediatric cardiologist occurred. Weekly non-stress testing along with ultrasound for signs of cardiac failure were done.  At 38+ weeks  left ventricular enlargement was identified. Fetal lung maturity was ascertained, an induction done resulting in infant born at 39 weeks 4 days with apgars 8/9, weight 3460 Gms. Infant echocardiogram showed multiple intracardiac lesions including a tumor obstructing aortic outflow near the aortic valve, one on the anterior leaflet of the mitral valve, a tumor in the left ventricle 2/3 of ventricle size and multiple non-obstructive lesions. The infant was admitted to the NICU for monitoring. Family bonding with infant was encouraged and facilitated by nursing. At 26 hours of age, the infant developed supraventricular/ ventricular tachycardia to 400 tolerated poorly. Cardioversion was done and anti-arrhythmic drugs started. Parents were notified, options and the definitive diagnosis of tuberous sclerosis discussed. On day 11 of life, the infant had open heart surgery to remove tumors and did well postoperatively.

Conclusion: This family was not expecting a child with a significant health problem. Support from staff was crucial. Initially, they focused on the risks of cardiac surgery and not on the more significant diagnosis of TSC. However, the diagnosis and its implications were addressed by the multidisciplinary team. Tuberous sclerosis complex is an autosomal dominant multisystem disorder. Early diagnosis is critical since recent literature suggests that rapamycin use early may prevent the development of TSC manifestations.

Keywords:       Rhabdomyomas

                        Tuberous Sclerosis Complex (TSC)

                        Rapamycin

                        Fetal arrhythmia