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Irregular Heart Rate, Cardiac Arrhythmia (Arrhythmia) in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Urgent see a veterinarian within 24 hours

RED for syncope/collapse, respiratory distress, very fast or very slow heart rate, weak pulse, suspected chest pain, or sudden deterioration.

Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity

Definition

Cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems., also known as arrhythmias, are deviations from a dog’s normal heart rate or heart rhythm. These can manifest as an irregular beat, or the heart beating too fast or too slow.

Can Occur with the Following Diseases:

Basics and possible causes

A dog’s heart consists of four chambers that beat in a synchronized rhythm to pump blood efficiently through the body. The heart rhythm is controlled by electrical impulses generated by specialized cells in the heart. When these impulses are disrupted, arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. can occur.

There are many possible causes for cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. in dogs. A common cause is an underlying heart disease that affects the structure or function of the heart. This includes heart valve disease, dilated cardiomyopathy, or inflammation of the heart muscle.

Other causes can be metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. in nature, such as electrolyte imbalances or hormonal disorders, e.g., hyperthyroidism. ExogenousExogenous refers to factors or processes that act on an organism from the outside. This can include environmental influences, chemical substances, pathogens, and other external factors that affect health or behavior. factors such as certain medications, toxins, or even stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can also affect the heart and triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems..

Genetic factors also play a role. Certain breeds are more susceptible to specific heart problems, such as Dobermans for dilated cardiomyopathy or Cavalier King Charles Spaniels for mitral valve disease.

Typical accompanying symptoms

Weakness or collapse: A dog with cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. may suddenly become weak or even collapse, as irregular heartbeats can impair blood supply to the brain.
RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress: Shortness of breath or rapid breathing may occur as the body attempts to compensate for the lack of oxygen caused by inefficient heart function.
Lethargy or reduced resilience: Dogs with arrhythmias tire more quickly and may show less interest in physical activities.
Cough: A persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. cough can be a sign of fluid accumulation in the lungs caused by heart problems.
Altered heart sounds: During the examination, the veterinarian may detect irregular heartbeats or unusual noises.

When to see a vet?

A visit to the vet is urgently required if your dog shows signs of weakness, collapse, or respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress. These symptoms can indicate serious heart problems that require immediate attention.

Also, if you notice irregular heartbeats in your dog or if he shows sudden bouts of exhaustion that are not attributable to other causes, you should not hesitate to consult a veterinarian.

A regular health check is particularly important if your dog belongs to a breed that is prone to heart problems. Early detection can slow the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease and extend your dog’s life.

Symptom recognition for the pet owner and veterinary diagnostic procedure

As a pet owner, you can check your dog’s heart rate at home by placing your hand on the dog’s chest. An irregular rhythm can be an initialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. sign of a problem. Also watch for other symptoms such as respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress or unusual behavior.

The veterinarian will perform a thorough examination. This may include listening to the heart with a stethoscopeA stethoscope is a medical instrument used for auscultation, or listening to body sounds, such as heartbeats and lung sounds. It is a fundamental tool in medical diagnostics. to identify irregular sounds. An electrocardiogramSee ECG. (ECG) examination can help determine the type of arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems.. Blood tests may also be performed to identify possible underlying causes, such as electrolyte imbalances or hormonal problems.

In some cases, an ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. of the heart (echocardiogram) may be necessary to detect structural abnormalities or functional disorders. In difficult cases, a referral to a cardiologist for further testing may be necessary.

What the pet owner can do and professional therapy options

Until the veterinary examination, you should keep your dog as calm as possible to avoid unnecessary stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. and physical exertion. StressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can further affect the heart rate.

Ensure your dog has access to fresh water and try to provide a comfortable environment. Avoid giving your dog any medication unless it has been prescribed by a veterinarian.

If your dog shows signs of an acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. problem, such as severe respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress or a collapse, you should immediately visit the nearest veterinarian or veterinary hospital. Fast action can be life-saving in these cases.

Outlook on current research

Research into cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. in dogs has made significant progress in recent years. Scientists are increasingly focusing on the genetic causes of these conditions, as certain breeds like Dobermans and Boxers are more frequently affected by arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems.. Genome-wide association studies are identifying specific genes linked to a predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. for cardiac arrhythmia. In the future, these discoveries could enable the development of genetic tests that support early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. measures.

Another area of research is the development of non-invasive diagnostic tools. Technologies such as wearable ECG monitors allow veterinarians and researchers to monitor a dog’s heart activity over longer periods without stressing the animals in a clinical setting. This improves the accuracy of arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and allows for a better understanding of the circumstances under which they occur.

In therapeutic research, intensive work is being done to develop new medications specifically aimed at treating cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems. in dogs. Some promising approaches involve the use of antiarrhythmicAntiarrhythmic medications are substances used to treat and provide prevention of irregular heartbeats. They work by stabilizing the electrical activity of the heart. drugs that work at a molecular level to stabilize the heart’s electrical activity. Additionally, the use of stem cell therapies is being investigated, aiming to regenerate damaged heart tissue and improve electrical conductivity.

The role of diet and lifestyle is also being studied, as factors like obesityObesity is the medical term for severe overweight, characterized by an excessive accumulation of fat in the body. It is often defined by a body condition score that is above the ideal range. and lack of exercise can increase the risk of developing cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems.. Researchers are analyzing how specific diets rich in omega-3 fatty acids and regular exercise can strengthen the cardiovascular system and contribute to the preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems..

An exciting area of research is the study of the effect of environmental factors on canineCanine refers to anything related to dogs. The term is used to describe characteristics, diseases, or specific aspects that specifically affect dogs. heart health. Studies show that environmental stressors such as noise and air pollution can increase susceptibility to cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems.. These findings could lead to new recommendations for pet ownership to promote the well-being and heart health of dogs.

Frequently asked questions

1. What does an irregular heart rate mean in dogs?

An irregular heart rate in dogs refers to a deviation from the normal heartbeat rhythm. This can manifest as a heartbeat that is too fast, too slow, or irregular. It means the heart is not beating in a steady pattern, which can affect the efficiency of blood circulation in the body.

2. What symptoms may indicate cardiac arrhythmia in dogs?

Typical symptoms of cardiac arrhythmia in dogs include weakness, collapse, respiratory distress, cough, lethargy, and in severe cases, fainting. However, some dogs show no obvious symptoms, making regular veterinary check-ups important.

3. Are certain dog breeds more prone to cardiac arrhythmia?

Yes, certain dog breeds are genetically more susceptible to cardiac arrhythmia. These include Dobermans, Boxers, and Cavalier King Charles Spaniels. These breeds should have their heart health checked regularly to detect potential problems early.

4. How is cardiac arrhythmia diagnosed in dogs?

Cardiac arrhythmia is usually diagnosed using an electrocardiogram (ECG), which measures the electrical activity of the heart. Additional diagnostic tests may include an echocardiogram, X-rays, or blood tests to identify the underlying causes.

5. Can cardiac arrhythmias be treated in dogs?

Yes, cardiac arrhythmia can often be treated, especially if detected early. Treatment depends on the type and severity of the arrhythmia and may include medication, lifestyle changes, or in severe cases, surgical intervention.

6. Does diet affect the risk of cardiac arrhythmia in dogs?

Diet can have an impact on the risk of cardiac arrhythmia. A balanced diet rich in nutrients like omega-3 fatty acids can support heart health. Overweight should be avoided, as it increases the risk of heart problems.

7. Are cardiac arrhythmias life-threatening in dogs?

Cardiac arrhythmia can potentially be life-threatening, especially if left untreated. Severe arrhythmias can lead to heart failure or sudden cardiac death. Early diagnosis and therapy are crucial to minimize the risk of serious complications.

8. Can environmental factors trigger cardiac arrhythmia in dogs?

Yes, environmental factors such as stress, noise, and air pollution can increase the risk of cardiac arrhythmia. A calm and stress-free environment can help promote heart health in dogs.

9. Are there preventive measures against cardiac arrhythmia in dogs?

Prevention measures include a balanced diet, regular exercise, avoiding being overweight, and regular veterinary check-ups. For breeds with a genetic predisposition, special attention should be paid to heart health.

10. What role does exercise play in the prevention of cardiac arrhythmia?

Regular exercise is crucial for overall heart health. It helps maintain a healthy weight, improve circulation, and reduce stress, which can decrease the risk of cardiac arrhythmia.