Samuel (in Hebrew, Shmuel) does not mean “God has heard”: whoever told you that may be thinking it’s spelled שמוע-אל, i.e. “Shmua-el”, but it’s not. The consonant ayin is missing, and it doesn’t go missing lightly.
In the story of Samuel’s birth (I Sam. 1), Hannah, his mother, explains that she named him so—
כי מיהוה שאלתיו (ki meAdonai she’iltiv)