According to WebMD, a dog's resting heart rate is typically between 60 and 160 beats per minute. Large dogs have slower heart rates, while puppies' heart rates can run as fast as 220 beats per minute.
If a dog's heartbeat is exceedingly fast, the dog may be suffering from anemia, shock, heart disease, fever or dehydration. A dog with a very slow heartbeat may be showing signs of heart disease or circulatory collapse. Heart murmurs are common in dogs; they may indicate a serious condition or may be no cause for worry. It's possible to check a dog's heart rate without a stethoscope by placing an ear next to his chest and listening or by checking the pulse in his femoral artery.