GDP is the sum total of all economic output in the economy. Its growth is driven by increases in population and productivity, not interest rates. If I can earn a 20% return on an asset I may have no qualms about borrowing money at 10% to buy it. If I can only earn 5% then I sure wouldn't borrow at 10%.
So if the Feds raised the rate to 25% what would happen to GDP? If the Feds lowered the rate to 0% or went negative what would happen to GDP?