Apparent Life Threatening Events, Sudden Infant Death Syndrome and Muscarinic Receptors

Apparent Life-Threatening Events (ALTE) in infants often lead to severe neurological complications or to sudden death. In such situations, cardio-pediatricians and intensive care physicians have no specific diagnosis or treatment. In a recent translational research (INSERM-DHOS), our team has reported a myocardiac abnormality in a rabbit model of vagal hyperreactivity which is also present in the human hearts of infants deceased from sudden death, i.e. increased M2 muscarinic receptors (M2R) density associated with compensative increased enzymatic activity and overexpression of acetylcholine esterase (AchE). In a recent PHRC-I study (article in preparation), these abnormalities have also been observed in the blood of patients, infants as well as adults, exhibiting severe vagal syncopes. We observed, even more importantly, similar abnormalities in infants under 1 year of age with very severe idiopathic ALTE (iALTE) compared with normal subjects and with patients who presented ALTE with identified etiologies (JAMA Pediatric, 2016 May). The aim of this present study is to validate the overexpression of M2R as a marker of risk of iALTE in infant under 1 year.

Inclusion Criteria: * Infant aged between 28 days and 12 months, presenting severe syncope(s) requiring medical management, hospitalized in a pediatric intensive care unit or pediatric emergencies * Consent signed and dated by the legal representatives * Patients affiliated to a social security system Exclusion Criteria: * Infant with known cardiovascular, neurologic, infectious, toxic or metabolic pathologies before enrollment (before the syncope) * Subject on medication for more than 3 months before enrollment * Impossibility to clearly inform the legal representatives (comprehension problems) * Subject in exclusion period for clinical trial (previous or current study)