Reasons Your Pet’s Heart Rate Might Be Faster Than Normal (tachycardia):
Nervousness, fear or excitement are the most common causes for a fast heart rate in your dog or cat. That is especially true when your pet confronts stressful or uncertain situations – like a trip to your veterinarian’s office. “Stress-free” and “Fear-free” veterinary visits might be engineered to be stress and fear free for you. But they are never going to be for the majority of pets.
Pets in late pregnancy (particularly with large litters) or an overdose of medication (thyroid meds, catecholamines, amphetamine, caffeine, Sudafed®, theophylline, atropine overdose, etc.) also can raise your dog and cat’s heart rate.
All medications that are considered stimulants (like like caffeine, chocolate or ADHD medications) can increase your dog and cat’s heart rate when consumed accidentally or in excessive amounts. Too high a dose of thyroid medications (e.g. levothyroxine) can also cause increased respiratory rate. Other medications, like phenylpropanolamine (Proin®), that are given to older female dogs to control bladder leakage (and occasionally to cats as well) can elevate blood pressure but appear to have no effect on heart rate.
Ron Hines DVM PhD
Your dog and cat’s heart rate seems like such an elementary thing. But it gives veterinarians like me a great deal of information when it comes to understanding your pet’s heart health.
You can hear or feel much of what your veterinarian hears through his/her stethoscope if you ask to borrow one. Simply put your ear against your pet’s chest while you feel its pulse in its groin. Without a stethoscope, you won’t hear typical heart murmurs unless they are quite severe. Your pet’s heart rate or rhythm felt in its groin (femoral pulse) provides considerable important information as well.
Your pet’s heartbeat and pulse should be strong and regular. It is normal for the rhythm of your dog and cat’s heart to change a bit in time with your pet’s breathing (normal sinus arrhythmia). That occurs to a lesser extent in healthy people. Heart rate and respiratory rate often go up or down together since both are adjusting to the dog or cat’s current oxygen needs through the vagus nerve.
Large dogs usually have somewhat slower heart rates than small dogs and cats; while puppies and kittens have a slightly faster pulse and heart rhythm. Erratic (arrhythmic) pulses and abnormally slow pulses (bradycardia) or weak pulses often exist together and share many common causes.
Reasons Why Your Dog Or Cat’s Heart Rate Might Be Slower Than Normal (= Bradycardia):
Reasons include: heart disease in cats and dogs, trauma to the head (as in “bell-ringer” car accidents), increased pressure surrounding the brain (hydrocephalus) can all affect the centers controlling your dog and cat’s heart rate. That problem is most common in apple headed miniature breeds. Read about that and other genetic birth defects here.
All forms of circulatory collapse, shock or coma can slow heart rate as well.
Canine athletes have slower heart rates than their couch potato relatives. That is nothing to worry about if your pet is healthy in other ways.
Situations of low body temperature (hypothermia), low blood sugar (hypoglycemia), sedative medications or terminal FIP disease in cats can all produce slow heart rates.
Elevated blood potassium levels (hyperkalemia), heart electrical circuitry failure (AV heart block, complete heart block), or hypothyroidism in dogs can cause a slower heart rate.
Overdose of many medications/sedatives (e.g. insulin, narcotics, general anesthetics, xylazine (Rompun®), digoxin, amlodipine and other calcium channel blockers, insecticides, propranolol and other beta-blockers, alcohol, neostigmine and other acetylcholinesterase inhibitors, etc.) will all slow your pet’s heart rate.
Some rare diseases such as “sick sinus syndrome” (especially in old miniature schnauzers) cause slow heart rate.
Benign sinus bradycardia (SB) occasionally occurs in dogs that have no apparent ill health. It appears to be due to a sinoatrial node abnormality present from birth. SB occasionally occurs in immature or young dogs, especially cockers, dachshunds, pugs, westies and miniature schnauzers.
How to Check a Dog’s Heart Rate At Home (Accurate Method)
Concerned pet parents ask veterinarian Dr. Lee Pickett for pet medical advice about abnormal heart rhythms in dogs.
Q:I am in high school and want to become a veterinarian, so I’ve been listening to my pets’ hearts with a stethoscope. My dog’s heart rate varies considerably, going from fast to slow to fast again, but my cat’s heart beats steadily – as does mine, even though I am worried about my dog. Does he have heart disease?
A:What you likely hear is called sinus arrhythmia, and it’s normal in dogs, but not in cats.
In relaxed dogs, the heart rate quickens during inhalation and slows when the dog exhales and pauses between breaths. By comparison, a cat’s heartbeat remains steady.
To convince yourself that your dog’s changes in heart rhythm constitute normal sinus arrhythmia, take him for a run and, while his heart rate is still elevated from the exertion, listen again. You should hear steady, evenly spaced heart beats.
If you are in doubt about his heart, ask your veterinarian to listen and be prepared with dog insurance.
No one is permitted to sell, solicit or negotiate an insurance policy without a producer license in the state in which the plan is sold, and all prospects should be directed to Figo Pet Insurance. The information contained in this website is for illustrative purposes only and coverage under any pet insurance policy is expressly subject to the conditions, restrictions, limitations, exclusions (including pre-existing conditions), and terms of the policy documentation issued by the insurer. Availability of this program is subject to each state’s approval and coverage may vary by state. Coverage underwritten by Independence American Insurance Company (IAIC), a Delaware Insurance Company, 11333 North Scottsdale Road Suite 160 Scottsdale, AZ 85254. Live Vet and the Figo Pet Cloud are separate non-insurance services unaffiliated with IAIC.