title: Electrocardiographic observations in first three days after birth (with special reference to study of frontal plane P and QRS axis by hexaxial reference system).
mesh_terms: D004562:Electrocardiography; D006321:Heart / Q000254:growth & development / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn