CONGRESS ABSTRACT

BACKGROUND: Hypertrophic Cardiomyopathy (HCM) presenting during the neonatal period has different etiologies, risk factors, and clinical course comparing to HCM with onset during childhood, adolescence or adult age. Noonan and mitochondrial disease have the worst prognosis among all neonatal HCM. PURPOSE: We aim to describe the clinical course and survival and of HCM associated to Noonan and mitochondrial diseases with neonatal onset in a single-centre retrospective study. METHODS: All consecutive newborns with HCM diagnosis referred to our centre were enrolled. Demographic and clinical data as survival (defined as freedom from cardiac death or heart transplantation) and adverse event (AE) including ICD implantation and myectomy were analysed. Categorical variables are expressed as absolute numbers or percentages. Continuous variables are presented as mean value and standard deviation (SD). Survival analysis and freedom from adverse event were analysed and reported by Kaplan Meier curves. RESULTS: 26 HCM patients with neonatal onset were included in the analysis, specifically 17 neonates with Noonan syndrome (40%) and 9 with mitochondrial diseases (21%). At the time of diagnosis, early treatment with beta-blockers was started and up-titrated to highest tolerated dosage (propranolol mean dosage 15 ± 10 mg/kg) in all patients. Kaplan Meier analysis showed a survival at 6 months of 94% in patients with Noonan syndrome and of 89% in patients with mitochondrial disorders. After a 6-month follow-up (FU), surviving patients were stabilized and no other cases of death or heart transplantation were recorded during the next FU (main FU 7 +/- 6.4 years). During FU, 4 patients with Noonan syndrome (23%) underwent myectomy before 15 years of age and an implantable cardioverter-defibrillator (ICD) was implanted in 2 patients (12%) during adolescence. No cases of myectomy or ICD implantation were recorded in the mitochondrial group. CONCLUSIONS: Noonan and mitochondrial disorders represent the great majority of neonatal HCM. In our series a higher rate of survival compared to previously reported data in these patients was observed, potentially related to early treatment and high dosage of beta-blockers. Further studies are needed to identify the optimal management of this group of patients.