If your dog's heart is beating fast, you are likely concerned. A dog’s heart beats with a marvelous efficiency, increasing the flow of blood to the lungs and the rest of the body during exercise and then returning to a slower rate when resting. While the human’s heart usually beats with a machine-like rhythm, the dog’s heartbeat has a natural lack of rhythm, but this feature rarely causes medical problems.
The Normal Heart Rate in Dogs
The heartbeat is the rhythmic pumping of the heart muscle. It is controlled by a group of cells called the pacemaker, which produces electrical signals to stimulate the muscle to contract. The beating can be felt as a pulse in places where arteries lie just under the skin. A normal heartbeat is distinct, while a beat produced by a diseased heart with damaged valves, produces more of a vibration or buzz.
What is the normal heart rate for dogs? Generally speaking, the normal heart in dogs rates vary from 50 beats per minute (bpm) in large dogs to 160 beats per minute (bpm) in small dogs.
More precisely speaking, a dog’s heart rate depends on two factors: the dog’s age and size. Smaller dogs and puppies have distinctively higher heart rates than larger and adult dogs.
For example, the resting heart rate in puppies varies between 160 and 200 beats per minute. In some cases it can be as high as 220 beats per minute. Dogs at the age of 1 have a resting heart rate of up to 180 beats per minute.
The resting heart rate in large adult dog is between 60 and 100 beat per minute and in small adult dogs is between 100 and 140 beats per minute.
It should also be noted that dogs that are out of shape have higher heart rates than dogs that are in good physical condition.
How to Measure a Dog's Heart Rate?
You can gain some idea of the health of a dog’s heart and circulation by feeling the pulse or heartbeat. The pulse is most easily felt in the femoral arteries (inside the thigh where the hind leg joins the body).
For thin dogs, feel the heartbeat by pressing your left fingers on the chest wall just behind the left elbow. For small dogs, gasp the chest underneath, with your fingers on the left side and gently squeeze. Count the beats for 15 seconds and multiply by four to find the pulse or heart rate.
It is advisable to check your dog’s heart rate multiple times while it is healthy and resting. That way you will be able to establish a baseline and determine whether a problem is starting to present.
Help, My Dog's Heart is Beating Fast
In a nutshell, the medical term tachycardia indicates an abnormally increased or rapid heart rate. Tachycardia can be caused by a plethora of different causes classified in 2 main groups: physiological causes and pathological causes.
Tachycardia occurs when the heart rate is higher than 220 bpm in puppies, 180 bpm in small dogs, 160 bpm in medium-sized dogs and 140 bpm in large dogs.
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Increased Heart Rate in Dogs – Physiological Causes
The heart rate normally increases during physical activity – the more challenging the physical activity the higher the heart rate. Significant emotional responses, like excitement and stress can also trigger an increase in the heart rate.
In a nutshell, the physiological causes of tachycardia include: exercise, restrain, pain, excitement, anxiety, anger and fear.
Increased Heart Rate in Dogs – Pathological Causes
If a resting dog experiences an increased heart rate, it is time to make an appointment at the vet’s office. Tachycardia may occur as a result of several serious and potentially life-threatening heart and blood issues. Pain can also lead to increased heart rate.
In dogs, there are three types of tachycardia: atrial, ventricular and sinus.These types are differentiated based on the location within the heart where the abnormality originates. Each type has different underlying causes and consequently different potential complications as well as different treatments and outcomes.
Different types of tachycardia have different underlying causes. Atrial tachycardia is usually caused by heart conditions and certain systemic illnesses. Sinus tachycardia can be caused by stress, excitement, exercise, pain and heart problems. Ventricular tachycardia can be caused by congenital deformities, heart problems (mainly congestive heart failure), anemia, lung diseases, sepsis, tumors, dehydration, gastrointestinal issues, pancreatitis, myocarditis and certain drugs overdose. Ventricular tachycardia is the most serious type of tachycardia. Luckily, in most cases, with proper strategy it can be successfully managed.
Dogs with a pre-existing heart condition are at higher risk of experiencing episodes of increased heart rate. The risk is also higher in dogs on thyroid medication, dogs suffering from inflammation and pregnant bitches.
Signs a Dog's Heart is Beating Fast
More often than not, dogs can experience increased heart rate episodes without showing other clinical signs, especially if there is no underlying cause. However, sometimes, additional clinical signs can be present.
The most common symptoms of tachycardia in dogs are:
- Lightheaded feeling
- Shortness of breath
- Exercise intolerance
- Sudden weakness
- Pale mucous membranes
- Blood clots
- Chest pain due to angina
- Heart attack
At the Vet's Office
What's the treatment for a high heart rate in dogs? The course of treatment depends on the underlying cause. Regardless of the strategy, the goal of the treatment is the same – correcting the underlying issue and normalizing the heart rate.
The heart rate can be normalized with:
- Medications – such as lidocaine and sotalol
- Vagal maneuver – includes stimulating the vagal nerve by pressing the ocular or carotid sinus which results in decreased heart rate
- Electrical cardioversion – includes restoring the heart rate by introducing an electric shock
- Pacemaker – this approach is used in extremely severe cases
- Open heart surgery.
Depending on the underlying cause, your dog may need life-long administration of medications. Additionally, in most cases it is advisable to restrict the dog’s physical activity.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.
She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.