The commentaries explain that the "high places of Isaac" is referring to the altars that the Jews built to worship their idols. The verse is intimating that everyone will be so preoccupied with their afflictions that they will not have the time or the inclination to worship their idols. Using the word Isaac to describe the Children of Israel is unique. Normally the Jewish Nation is described as the Children of Jacob or the Children of Israel (Jacob's other name) but they are not described as the Children of Isaac. The Rabbis explain that their worshiping of idols made them seem to be like the wicked Esau who was the son of Isaac.
