Although still in testing phase,thelightning network can now be used to send transactions across different blockchains. The Lightning Labs development team successfully swapped testnet bitcoin for testnet litecoin through a lightning channel this week ownership of the coins changed hands, while no transaction was recorded on either blockchain.Previous atomic swaps that I have done were on-chain, and had the on-chain limitations of slow transactions and high transaction fees, Litecoin creator

Source and More information: The Lightning Network Now Supports Transactions Across Blockchains

Author: CryptScout.com