Agonal breathing usually sounds like loud snoring, gurgling, choking, or moaning. Some people describe it as a wet rasping noise or a low groan. It is not the soft, regular sound of normal breathing, and it comes in slow gasps rather than a steady rhythm.
Witnesses often describe being startled by how loud the sound is. It can be loud enough to wake someone in another room, which is sometimes how a cardiac arrest at home is first noticed. Despite how dramatic the sound is, the person making it is unresponsive and not breathing properly.