How long does a heart take to be stopped when he is euthanized?

When an animal is euthanized, the veterinarian typically administers a combination of drugs that quickly and painlessly stop the heart. The drugs used for euthanasia are typically a barbiturate or a combination of a barbiturate and a muscle relaxant. These drugs work by depressing the central nervous system, which causes the animal to lose consciousness and stop breathing. The heart will typically stop beating within a few seconds after the drugs are administered.