Slow heart rate (bradycardia) in Dogs
When to visit the vet?
Urgent see a veterinarian within 24 hours
RED in case of collapse/syncope, weakness, shortness of breath, hypothermia, neurological symptoms (e.g., increased intracranial pressure), or if the pulse is barely palpable.
Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity
Definition of
Bradycardia is a medical condition in which a dog’s heart rate falls below the normal range. In dogs, this low heart rate can vary depending on the breed, age, and size of the animal. Generally, a heart rate below 60 to 70 beats per minute in large dogs and below 80 to 100 beats per minute in small dogs is considered bradycardia.
Can Occur with the Following Diseases:
- Slow and Irregular Heart Rhythm in Dogs (Bradyarrhythmia)
- Abnormally Slow Heart Rate in Dogs (Bradycardia)
- Enlarged Heart Disease in Dogs (Dilated Cardiomyopathy, DCM)
- Dysautonomia in Dogs (Key-Gaskell Syndrome)
- Irregular Heartbeat in Dogs (Cardiac Arrhythmia)
- Low Body Temperature in Dogs (Hypothermia)
- Underactive Thyroid Gland in Dogs (Hypothyroidism)
- Underactive adrenal cortex in dogs (hypoadrenocorticism, Addison’s disease)
- Abnormal Heart Rhythm with Slow Heart Rate in Dogs (Sick Sinus Syndrome/Bradyarrhythmia)
Grundlagen und mögliche Ursachen
A dog’s heart rate is regulated by the autonomic nervous system, which includes both the sympathetic and parasympathetic divisions. The sympathetic division is responsible for increasing heart rate, while the parasympathetic division, particularly the vagus nerve, lowers heart rate. Excessive activation of the vagus nerve can therefore lead to bradycardia.
Bradycardia can be caused by a variety of factors. One of the most common reasons is a disturbance in the heart’s electrical system, such as in sick sinus syndrome or atrioventricular block. These problems can be either congenital or acquired.
Other causes include systemic diseases such as hypothyroidism, where the thyroid gland does not produce enough hormones, or hypothermia, where the dog’s body is undercooled. Certain medications, especially those that affect the heart, such as beta blockers or antiarrhythmics, can also lead to a reduced heart rate.
Poisoning, particularly by certain pesticides or plants, can also cause bradycardia. In some cases, bradycardia can be a sign of a more serious heart condition or a systemic illness that requires immediate veterinary intervention.
Typische Begleitsymptome
- Weakness: Dogs with bradycardia may appear weak and lethargic due to reduced cardiac output. This results from an insufficient supply of oxygen-rich blood to the body.
- Loss of consciousness: In severe cases, fainting or collapse may occur because the brain does not receive enough blood and oxygen.
- Respiratory distress: Some dogs show respiratory distress or rapid, shallow breathing as the body tries to compensate for the lack of oxygen.
- Pale gums: Reduced blood flow can lead to pale or bluish gums, which is a sign of poor oxygenation.
- Altered heart sounds: During the examination, the veterinarian may detect abnormal heart sounds or an irregular heartbeat.
Wann zum Tierarzt?
A veterinary visit is urgently needed if your dog shows signs of weakness, fainting, or respiratory distress. These symptoms may indicate a serious undersupply of blood and oxygen to the body and require immediate medical attention.
If you notice a change in your dog’s heart rate or if he seems unusually lethargic or weak, it is advisable to see a veterinarian as soon as possible. Even if the symptoms appear mild, they may be an indicator of an underlying problem that could worsen.
Symptomerkennung für den Tierhalter und tierärztliches diagnostisches Vorgehen
As a pet owner, you can check your dog’s heart rate at home by placing your hand on his chest and counting the number of heartbeats per minute. An unusually slow rate should be associated with other symptoms to decide if a veterinary visit is necessary.
At the vet, a thorough physical examination will be performed to assess your dog’s general health. An electrocardiogram (ECG) can be used to monitor the electrical activity of the heart and detect any abnormalities.
Blood tests may also be performed to look for systemic diseases or electrolyte imbalances that could affect heart rate. In some cases, further diagnostic imaging procedures, such as X-rays or ultrasound of the heart, may be necessary to rule out structural problems.
Was kann der Tierhalter tun und professionelle Therapieoptionen
As a pet owner, it is important to remain calm and place your dog in a comfortable position if you notice signs of bradycardia. Avoid physical exertion and stress, which could worsen the situation.
If you know that your dog is taking medications that could affect his heart rate, check the dosage and consult your veterinarian to determine if an adjustment is necessary.
Make sure your dog stays hydrated, as dehydration can impair heart function. Pay attention to a balanced diet to support your dog’s overall health.
In some cases, emergency treatment may be necessary, especially if your dog collapses or does not respond to external stimuli. Do not hesitate to seek immediate veterinary help to minimize the risk of serious consequences.
Ausblick auf aktuelle Forschung
Research into bradycardia in dogs is increasingly focusing on the genetic and environmental factors that can lead to a reduced heart rate. Scientists are investigating the role of genetic predispositions, especially in certain breeds that may be more susceptible to bradycardia. It is believed that genetic markers could be identified to aid in early detection and provide valuable information to veterinarians for implementing preventive measures.
Another promising area of research is the development of new diagnostic technologies. Advances in wearable heart monitors and non-invasive measurement methods make it possible to monitor dogs’ heart activity over longer periods. These technologies can help detect subtle changes in heart rate that indicate incipient bradycardia before clinical symptoms appear.
Additionally, intensive research is being conducted on the development of drugs specifically aimed at regulating heart rate. These medications could represent an alternative or complementary therapy to existing treatments. Researchers are also investigating the effect of diets and nutritional supplements that could support the cardiovascular system to stabilize heart rate in affected dogs.
In the area of prevention, research is exploring how lifestyle changes can reduce the risk of bradycardia. Studies suggest that regular physical activity, weight management, and stress reduction could have positive effects on heart health. These findings could lead to new guidelines for dog care and husbandry in the future to minimize the risk of bradycardia.
Finally, the role of environmental factors and their influence on heart rate is being investigated. Environmental toxins, air pollution, and even noise pollution could potentially affect the heart health of dogs. Long-term studies are underway to better understand the effects of these factors and to develop appropriate protective measures.