1、What is LTV ?

The maximum borrowing power of a specific collateral. If a collateral has a Loan to Value of 75%, for every 1 ETH worth of collateral the user will be able to borrow 0.75 ETH worth of principal currency. The Loan To Value is specified per collateral and expressed in percentage points.

2、What does this field affect?

Amount available for loan which means:
Max Borrow = Supply*LTV = The amount that has been borrowed + the amount that will be borrowed

For Example :

Single Currency Lending

Supply 100 USDT
The Value You Can Borrow = 100(In Current USD) * 0.7

Multi-Currency Lending

Supply 100 USDT & 10000 NAVX
The Value You Can Borrow = (100* Current USD Value Of USDT* 0.7 )+(10000* Current USD Value Of NAVX*0.2)