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Irregular Heart Rate, Cardiac Arrhythmia (Arrhythmia) in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Are you unsure what is wrong with your pet? Feel free to use our symptom checker for more clarity.

Cardiac arrhythmias, also known as arrhythmias, are deviations from a dog’s normal heart rate or 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 efficiently pump blood through the body. The heart rhythm is controlled by electrical impulses generated by specialized cells in the heart. If these impulses are disrupted, arrhythmias can occur.

There are many possible causes of 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 condition that affects the structure or function of the heart. These include heart valve disease, dilated cardiomyopathy, or myocarditis.

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. arrhythmias.

Genetic factors also play a role. Certain breeds are more prone to certain 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 visit the vet?

A visit to the veterinarian is urgently needed 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 may 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 especially 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 prolong your dog’s life.

Symptom recognition for animal owners and veterinary diagnostic procedures

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 early 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.

A thorough examination will be performed at the veterinarian. 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 can 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 dysfunctions. In difficult cases, a referral to a cardiologist may be necessary for further investigations.

What can pet owners do and professional therapy options

Until the veterinary examination, 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 strain. 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.

Make sure your dog has access to fresh water and try to provide him with a comfortable environment. Avoid giving your dog medication unless 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 shortness of breath or collapse, you should immediately consult the nearest veterinarian or a veterinary hospital. Prompt action can be life-saving in these cases.

Outlook on current research

Research into cardiac arrhythmias in dogs has made significant progress in recent years. Scientists are increasingly focusing on the genetic causes of these diseases, as certain breeds such as Dobermans and Boxers are more frequently affected by arrhythmias. Genome-wide association studies are identifying specific genes associated with 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. 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 discoveries could enable the development of genetic tests in the future to 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 preventive 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 the heart activity of dogs over extended 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 carried out to develop new drugs specifically targeting the treatment of cardiac arrhythmias in dogs. Some of the promising approaches involve the use of antiarrhythmics that act at the molecular level to stabilize the electrical activity of the heart. In addition, the application of stem cell therapies is being investigated, which aim to regenerate damaged heart tissue and improve electrical conductivity.

The role of nutrition and lifestyle is also being investigated, as factors such as 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 arrhythmias. Researchers are analyzing how specific diets rich in omega-3 fatty acids and regular exercise can strengthen the cardiovascular system and help prevent arrhythmias.

An exciting area of research is the investigation of the effect of environmental factors on the heart health of dogs. Studies show that environmental stressors such as noise and air pollution can increase susceptibility to cardiac arrhythmias. These findings could lead to new recommendations for animal husbandry to promote the well-being and heart health of dogs.

Frequently asked questions

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 that the heart is not beating in a consistent pattern, which can affect the efficiency of blood circulation in the body.
What symptoms may indicate cardiac arrhythmia in dogs? Typical symptoms of 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 include weakness, collapse, respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, cough, lethargy, and in severe cases, fainting. However, some dogs do not show obvious symptoms, so regular veterinary check-ups are important.
Are certain dog breeds more prone 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.? Yes, certain dog breeds are genetically more prone 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 include Dobermans, Boxers, and Cavalier King Charles Spaniels. These breeds should be regularly screened for heart health to detect potential problems early.
How is 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. diagnosed in dogs? Cardiac arrhythmias are usually diagnosed by an electrocardiogramSee ECG. (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.
Can cardiac arrhythmias be treated in dogs? Yes, cardiac arrhythmias can often be treated, especially if detected early. Treatment depends on the type and severity of the 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. and may include medications, lifestyle changes, or, in severe cases, surgical procedures.
Does diet affect the risk of 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? Diet can have an impact on the risk of 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.. A balanced diet rich in nutrients such as omega-3 fatty acids can support heart health. Overweight should be avoided as it increases the risk of heart problems.
Are cardiac arrhythmias life-threatening in dogs? Cardiac arrhythmias can be potentially life-threatening, especially if left untreated. Severe arrhythmias can lead to heart failure or sudden cardiac death. 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 treatment are crucial to minimize the risk of serious complications.
Can environmental factors 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. 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? Yes, environmental factors such as 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., noise, and air pollution can increase the risk of 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.. A calm and stress-free environment can help promote the heart health of dogs.
Are there preventive measures against 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? Preventive measures include a balanced diet, regular exercise, avoiding overweight, and regular veterinary check-ups. In breeds with a genetic 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., special attention should be paid to heart health.
What role does exercise play in the preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of 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.? Regular exercise is crucial for overall heart health. It helps maintain a healthy weight, improve circulation, and reduce 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., which can reduce the risk of 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..