The left ventricular torsion during systole and diastole is a normal dynamic mechanism which participates in the ejection and the filling of the left ventricle. Postnatal hemodynamic modifications are major and probably affect this mechanism. The aim of this study is to compare the left ventricular twist in healthy newborns, between their first days of life and their third month of life, using the 2D-speckle tracking echocardiography.

The left ventricular torsion during systole and diastole is a normal dynamic mechanism which participates in the ejection and the filling of the left ventricle. Postnatal hemodynamic modifications are major and probably affect this mechanism.

The main objective is to compare the left ventricular twist mechanism in healthy newborns, at birth and at their third month of life, using the peak LV twist as primary endpoint. Secondarily, we compare other LV rotation and deformation parameters during the same period: peak LV torsion, peak LV twist rate, peak LV untwist rate, circumferential strain and radial strain. Finally, we compare the endo- and epicardial LV deformation, using the inner and outer circumferential strain as endpoints.

This is a longitudinal, prospective and monocentric study in the Grenoble-Alpes University Hospital between April 2018 and September 2018.

The number of required subjects is 30 with a statistical power of 80% and a p-value of 0,05

Inclusion Criteria:

• Newborn hospitalized in the Grenoble University Hospital Maternity Unit
• Aged between 2 and 5 day of life at the first echocardiography
• Social security affiliation
• Signature of the consent document by both parents

Exclusion Criteria:

• Birth before 37 weeks gestation
• Birth weight < 2,5kg or > 4,5kg
• Gestational Diabetes Mellitus during pregnancy
• Fetal heart disease