Albert Barnes Commentary 2 Chronicles 28:7

"And Zichri, a mighty man of Ephraim, slew Maaseiah the king`s son, and Azrikam the ruler of the house, and Elkanah that was next to the king." — 2 Chronicles 28:7 (ASV)

Maaseiah was either an officer called “the king’s son” (Compare to 1 Kings 22:26), or perhaps a son of Jotham, since Ahaz could hardly have had a son old enough to take part in the battle (Compare to 2 Chronicles 28:1).

Elkanah, as “second to the king,” was probably the chief of the royal counselors.