Wait....what? ISIS?

It is Islamic State of Iraq and Syria. But that is not important here. You are confising something here. Bitcoin is a Currency with Finite Supply it will never inflate instead it will rather deflate:
Because the monetary base of bitcoins cannot be expanded, the currency would be subject to severe deflation if it becomes widely used. Keynesian economists argue that deflation is bad for an economy because it incentivises individuals and businesses to save money rather than invest in businesses and create jobs. The Austrian school of thought counters this criticism, claiming that as deflation occurs in all stages of production, entrepreneurs who invest benefit from it. As a result, profit ratios tend to stay the same and only their magnitudes change. In other words, in a deflationary environment, goods and services decrease in price, but at the same time the cost for the production of these goods and services tend to decrease proportionally, effectively not affecting profits. Price deflation encourages an increase in hoarding - hence savings - which in turn tends to lower interest rates and increase the incentive for entrepreneurs to invest in projects of longer term.
You can read detalied explanation here:
https://en.bitcoin.it/wiki/Controlled_supply