[Idiopathic left anterior hemiblock in a child (author's transl)].
Authors present a child three years old with an idiopathic left anterior hemiblock. Causes of left anterior hemiblock in children are reviewed, and it is concluded that although a left anterior hemiblock justifies a thorough non-invasive cardiologic and sistematic study and long-term follow-up, sometimes it may be the expression of an anatomic and/or physiologic variant.