Really low frame rate so it's hard to tell what may have happened. It looks like he might have been speared right in the heart.
These hacks and slashes happen so fast they are often missed by the human eye so sometimes you need really high speed film to see where the injuries occur, as is the case with the Sedin twins. Luckily they have a high pain threshold and incredible resiliency and are back in the play in no time flat.