Are you sure that's a letter H at the end. More usual is to see things like 1/2CIV ie. 1/2C<roman numeral>. This means hold a half barre (usually across the 2 highest pitched strings) at the fret indicated by the roman numeral (IV=fret 4 in this case). You might also come across the notation C<roman numeral><number subscript> eg CII4, meaning hold a barre at fret 2 across 4 strings.