How Big is a Chihuahua’s Heart? (+ 7 Heart Health Tips)

If you’re a Chihuahua owner or simply curious about the breed, you might be wondering “how big is a Chihuahua’s heart?

These pint-sized pups steal our hearts with their personality, but it’s their actual heart health that deserves our attention.

In this blog post, we’ll delve into the intricacies of Chihuahua heart health and the common conditions that can affect them. 

From understanding their heart size to discovering proactive steps for better heart health, we’ll uncover the insights you need to ensure your Chihuahua’s well-being.

a tan chihuahua is lying on its back in the grass with his tongue out and a red paper heart on its chest

How Big Is A Chihuahua’s Heart?

A Chihuahua’s heart is roughly the size of a grape or a walnut. 

While this may seem small, their hearts are proportional to their body size and function just as well as larger dog breeds.

To measure the exact heart size in dogs, vets use the vertebral heart size, also known as the vertebral heart score (VHS). 

To calculate a dog’s VHS, a vet will take a lateral x-ray of the dog laying on its side. Then they will measure the heart and compare it to the vertebrae of the spine.

Dogs usually have a VHS of 8.4 to 10.5. If the VHS is higher than 10.5, they probably have an enlarged heart.

The heart-to-body-mass ratio is also used for measuring a dog’s heart. It is a measure of the weight of their heart relative to the weight of their entire body. 

According to this study, the heart weight of a dog ranged from 0.6 to 1.1%of their body weight.

It found the absolute weight of the heart of a medium size dog, for example, is 40 to 600 grams which would be 0.9 to 2.2% of their body weight.

This means the estimated heart weight of a 6 lb Chihuahua would be between 16 and 30 grams.

What Is A Chihuahua’s Heart Rate?

a tan long haired chihuahua is standing with a red paper heart hanging around its neck

A healthy Chihuahua’s heart rate should be between 100 and 160 beats per minute (BPM).

Chihuahuas are small dogs, and their heart rate can be quite high compared to larger dog breeds. 

However, many factors can affect a Chihuahua’s heart rate, such as age, weight, activity level, and overall health.

You can check your Chihuahua’s heart rate by placing your hand on their chest and counting the number of beats per minute. 

Alternatively, you can use a stethoscope to listen to their heart rate.

If you notice that your Chihuahua’s heart rate is consistently outside the normal range, it’s essential to take them to the vet for a checkup. 

A high heart rate can be a sign of various health problems, including heart disease, dehydration, and anxiety.

Anatomy of A Dog Heart

The heart pumps blood throughout the body to deliver oxygen and nutrients to the tissues and organs. A dog’s heart is located on the left side of the chest.

a picture of the anatomy of a dog heart pointing out the 2 atriums and 2 ventricles

It’s made up of four chambers: the right and left atria and ventricles.

The atria receive blood from the body and lungs, while the ventricles pump blood out to the body and lungs. 

The right and left sides of the heart are separated by a muscular wall called the septum.

The heart is also surrounded by a protective sac called the pericardium, which contains a small amount of fluid to reduce friction as the heart beats. 

The heart is supplied with blood by the coronary arteries, which branch off the aorta and provide oxygen and nutrients to the heart muscle.

Human Heart vs Dog Heart

When it comes to size, a Chihuahua’s heart is proportionate to its body size, meaning it is smaller than a human heart. 

Despite this, the structure and function of a dog’s heart are similar to a human’s heart. 

One difference is that a dog’s heart has more heart muscle per pound of body weight than a human’s.

Here are some other key differences between a human heart and a dog’s heart.


A human heart is about the size of a large fist and weighs between 8-12 oz. A dog’s heart can vary depending on the breed and size. 

For example, a Chihuahua’s heart is about the size of a grape or walnut, while a Great Dane’s heart can be the size of a large fist.

Heart Rate

A dog’s heart rate is generally faster than a human’s heart rate. 

An average human heart rate is around 60-100 beats per minute, while a Chihuahua’s heart rate can range from 100-160 beats per minute.

Blood Pressure

Dogs can exhibit higher blood pressure levels compared to humans.

While the average human blood pressure hovers around 120/80 mmHg, with readings of 140/90 mmHg and above indicating high blood pressure. 

Dogs exhibit a range of 110/60 mmHg to 160/90 mmHg. Elevated blood pressure in dogs is recognized at levels exceeding 165/100 mmHg.

Common Chihuahua Heart Problems

If you own a Chihuahua, these are some of the most common heart conditions that can affect dogs.

Congestive Heart Failure (CHF)

Congestive heart failure occurs when the heart can no longer pump blood effectively.

Two causes include mitral valve insufficiency (a leaky valve) and dilated cardiomyopathy.

Symptoms in dogs include coughing, difficulty breathing, excessive panting, loss of appetite, weight loss, and bluish gums. 

Medication is used to manage symptoms and improve heart function.

Mitral Valve Disease (MVD)

Mitral valve disease is a condition in which the heart’s mitral valve doesn’t function properly, leading to backflow of blood.

It mainly affects small to medium-sized dogs.

Symptoms of mitral valve disease are coughing, difficulty breathing, and a swollen belly. 

Treatment may include medication like diuretics, ACE inhibitors, and pimobendan.

Patent Ductus Arteriosus

Patent ductus arteriosus is a congenital heart defect in which a blood vessel fails to close after birth. 

This condition can cause symptoms such as rapid breathing, coughing, a heart murmur, and weakness.

The most common treatment is surgery to close the blood vessel.

In 2018, a 3-month-old Chihuahua became the smallest patient at Auburn’s College of Veterinary Medicine to undergo Patent Ductus Arteriosus surgery. 

The procedure required the use of a retractor that is typically used to separate a horse’s eyelids to separate the Chihuahua’s ribs. 

Despite the challenges presented by the dog’s small size, the surgery was successful, and the Chihuahua made a full recovery.

Dilated Cardiomyopathy (DCM)

Dilated cardiomyopathy or enlarged heart is a condition in which the heart becomes enlarged and weakened, leading to poor blood circulation. 

DCM is rare in small breeds, affecting larger dogs more often.

Symptoms of DCM are coughing, rapid breathing, weight loss, distended belly, and restlessness.  

Typical treatment is aggressive and includes diuretics, ACE inhibitors, vasodilators, cardiac glycosides, and Pimobendan. 

Heart Murmur

a brown chihuahua is at the vet and she is putting a stethoscope to the chihuahua's chest

A heart murmur is an abnormal sound heard during a heartbeat. 

Heart murmurs can be caused by a variety of conditions, including mitral valve disease and patent ductus arteriosus. 

Treatment will depend on the underlying cause of the heart murmur.


Endocarditis is an infection of the heart’s inner lining. It typically affects the mitral and aortic valves.

Symptoms in the early stages are fever, weight loss, and lethargy. Later, dogs may develop signs of heart failure.

Antibiotics and medication is used to treat heart failure.

Heart Attack

A heart attack occurs when blood flow to the heart is blocked, leading to damage to the heart muscle. 

Do dogs experience heart attacks? They can, but it is rare.

Symptoms may include abnormal breathing, vomiting, high heart rate, confusion, or collapse. 

If you think you’re dog is experiencing a heart attack, go to a vet right away.

Treatment includes medication and supportive care.


An arrhythmia is an abnormal heart rhythm. 

Arrhythmias can be caused by a variety of conditions, including heart disease, congestive heart failure, infections, and electrolyte imbalances. 

Symptoms of an arrhythmia are weakness, long pauses between heartbeats, and loss of consciousness. 

Treatment will depend on the underlying cause of the arrhythmia.

7 Tips for a Healthy Heart

1. Regular Exercise

a tan chihuahua wearing a blue harness is panting and walking in the park

Regular exercise is essential for maintaining a healthy heart in your Chihuahua. 

Exercise helps to improve blood circulation, strengthen the heart muscle, and reduce the risk of heart disease. 

You should aim to provide your Chihuahua with at least 30 minutes of exercise every day. 

This can include walks, playtime, and other physical activities that your Chihuahua enjoys. 

If you need some new ideas for playtime, we have a post on the best games to play with your Chihuahua.

2. Healthy Diet

A healthy diet is also crucial for maintaining a healthy heart in your Chihuahua. 

You should provide your Chihuahua with a well-balanced diet that is rich in nutrients and low in fat. 

Avoid feeding your Chihuahua table scraps or unhealthy treats that can contribute to weight gain and heart disease.

Focus on offering treats that are specially designed for small dogs and are low-calorie. 

We have a guide that mentions 5 healthy treat options specifically for Chihuahuas. 

These treats can be used occasionally as rewards. Excessive consumption can undermine weight management efforts.

3. Maintain a Healthy Weight

Maintaining a healthy weight is essential for preventing heart disease in your Chihuahua. 

Just as with humans, carrying excess weight can significantly increase the risk of heart disease in dogs.

It can also contribute to a higher incidence of snoring.

It’s important to monitor your Chihuahua’s weight and provide them with a healthy diet and regular exercise. Remember to feed treats and chews in moderation.

4. Dental Health

a tan chihuahua is chewing on a bone holding it with his front paws

Dental health is also important for maintaining a healthy heart in your Chihuahua. 

Poor dental health can lead to infections that can spread to the heart and other organs. 

You should brush your Chihuahua’s teeth regularly and provide them with dental chews or toys to help keep their teeth clean.

Opting for professional dental cleanings performed by a veterinarian is a valuable choice if your dog can tolerate anesthesia.

These 8 natural and healthy chews are fantastic for enhancing your dog’s dental health.

5. Regular Vet Visits

Your vet can monitor your Chihuahua’s heart health and provide you with advice on how to maintain a healthy heart. 

They can also check for any underlying health issues that can contribute to heart disease.

6. Stress Management

Stress can also contribute to heart disease in your Chihuahua. 

Provide your Chihuahua with a safe and comfortable environment and avoid exposing them to stressful situations as much as possible.

Place their bed or crate in a quiet part of the house.

Toys and activities that can help reduce stress and anxiety include puzzle toys, snuffle mats, lick mats, and chews.

Licking and chewing release hormones that help your dog relax.

Some Chihuahuas are particularly sensitive to loud noises, so during thunderstorms or fireworks, create a sound-buffered space where they can find refuge, like a basement.

Playing music will also help to drown out the noise.

Being left alone can lead to stress if your Chihuahua has separation anxiety, so whenever possible, try to minimize the periods when they’re left alone or have someone watch them.

7. Avoid Smoke

Avoiding smoke exposure will help prevent heart disease in your Chihuahua. 

Smoke, whether from cigarettes or other sources like vapes or candles, can have adverse effects on their cardiovascular health. 

To safeguard their well-being, refrain from smoking in their presence and keep them away from secondhand smoke.


Now you have your answer to “how big is a Chihuahua’s heart.”

The heart of a Chihuahua is relatively small compared to other dog breeds. 

While Chihuahuas may be predisposed to certain heart conditions, such as mitral valve disease, it is possible to manage these conditions and improve the lifespan of your furry friend with proper care and treatment. 

Heart health is influenced by many factors, including genetics, diet, exercise, and overall lifestyle.

Regular check-ups with a veterinarian, a balanced diet, and regular exercise can all help maintain a healthy heart in your Chihuahua.

If dog science intrigues you, take a look at our blog posts about how big is a Chihuahua stomach and how big is a Chihuahua brain.


Where Is the Heart Located in a Chihuahua’s Body?

The heart of a Chihuahua is located in the chest, just behind the ribcage. It is positioned between the lungs and is surrounded by a sac called the pericardium.

What Is the Average Weight of a Chihuahua’s Heart?

The average weight of a Chihuahua’s heart is between 16 and 30 grams. It is about the size of a grape or walnut. However, it can vary depending on the size and overall health of the dog.

Are All Dogs’ Hearts the Same Size?

No, all dogs’ hearts are not the same size. The size of a dog’s heart varies depending on their breed, age, and overall health.

What Dog Has the Biggest Heart?

The dog breed known for having the biggest heart is the Great Dane. They have a larger heart to efficiently pump blood through their massive bodies.

How Do I Know If My Dog’s Heart Is Beating Too Fast?

You can check your dog’s heart rate by feeling their pulse or by using a stethoscope. A normal resting heart rate for a small dog is between 100-160 beats per minute. For a large dog, it’s between 65 and 90 beats per minute.

If you notice your dog’s heart rate is consistently higher than this, it’s best to consult with a vet.

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