[Vedran]

Well, it is not only shown, but documented in the Dungeon Master's Guide:

Death from Massive Damage In addition to dying when hit points reach 0, a character also runs the risk of dying abruptly when he suffers massive amounts of damage. A character who suffers 50 or more points of damage from a single attack must roll a successful saving throw vs. death, or he dies. This applies only if the damage was done by a single attack. Multiple attacks totaling 50 points in a single round don't require a saving throw. For example, a character would be required to make a check if a dragon breathed on him for 72 points of damage. He wouldn't have to do so if eight orcs hit him for a total of 53 points of damage in that round. If the saving throw is successful, the character remains alive (unless of course the 50-hit-point loss reduced his hit points to 0 or below). If the saving throw fails, the character immediately dies from the intense shock his body has taken. His hit points are reduced to 0. The character still can be raised in the normal ways, however.