Cardiac arrhythmia

What are cardiac arrhythmias?

A dog's normal heartbeat is controlled by an electrical impulse originating from the sinus node in the right atrium of the heart. This impulse spreads through the heart and causes the ventricles and atria to alternately contract and relax. This is how the blood is pumped through the body.

Cardiac arrhythmias are disorders of this electrical system that can lead to an irregular, too fast or too slow heartbeat. There are different types of cardiac arrhythmia, depending on where in the heart they occur and how they affect the heart. The most common are

• Sinus arrhythmia: A slight irregularity of the heartbeat that often occurs in young or athletic dogs. It is usually harmless and does not require treatment.
• Sinus bradycardia: A heartbeat that is too slow, below 60 beats per minute. It can occur in healthy dogs that are very relaxed or in dogs with certain conditions such as hypothyroidism, hypothermia or intoxication.
• Sinus tachycardia: A heartbeat that is too fast, above 160 beats per minute. It can occur in healthy dogs that are excited or stressed, or in dogs with certain medical conditions such as fever, anemia or pain.
• Atrial fibrillation: A rapid and irregular contraction of the atria that results in decreased pumping ability of the heart. It can occur in dogs with enlargement of the left atrium or heart muscle weakness.
• Ventricular fibrillation: A life-threatening disorder in which the heart chambers no longer beat synchronously, but twitch chaotically. The heart can no longer pump blood and the dog suffers cardiac arrest.
• AV block: An interruption or delay in the conduction of the electrical impulse from the atrium to the ventricle. There are different degrees of AV block, depending on how severely the conduction is impaired. An AV block can lead to a slow or irregular heartbeat and reduce the blood supply to the body.

How do you recognize cardiac arrhythmias in dogs?

Cardiac arrhythmias can cause different symptoms depending on how severely they affect blood flow. The most common symptoms are

• Weakness
• tiredness
• shortness of breath
• coughing
• Fainting
• Blue tongue or mucous membranes
• restlessness
• Anxiety
• Loss of appetite
• Weight loss

However, not all dogs with cardiac arrhythmia show symptoms. Some dogs only have occasional or slight deviations from the normal heartbeat that do not cause any symptoms. Other dogs have chronic or severe cardiac arrhythmias that severely limit their quality of life and life expectancy.

To diagnose cardiac arrhythmias in dogs, a vet must carry out a thorough examination. This includes listening to the heart with a stethoscope, measuring the blood pressure and taking an ECG (electrocardiogram). An ECG is a recording of the electrical activity of the heart, which is displayed on a screen or a strip of paper. The veterinarian can use the ECG to determine the type, frequency and severity of the cardiac arrhythmia.

How are cardiac arrhythmias treated in dogs?

The treatment of cardiac arrhythmias in dogs depends on the cause, type and severity of the disorder. Some dogs require no treatment if the arrhythmia is harmless or causes no symptoms. Other dogs require drug therapy to regulate the heartbeat, strengthen the heart or treat the underlying condition. In some cases, surgery or an implanted pacemaker may also be required to correct the heart's electrical system.

Treatment of cardiac arrhythmias in dogs requires regular monitoring by a veterinarian. The vet must check the dog's ECG, blood pressure and blood values to assess the effectiveness and side effects of the therapy. The dog owner must also pay attention to their dog's symptoms and behavior and contact the vet if necessary.

How can cardiac arrhythmias in dogs be prevented?

Cardiac arrhythmias in dogs are not always preventable, as they often have genetic or age-related causes. However, there are some measures that can be taken to reduce the risk or improve the prognosis. These include:

• A balanced diet that meets the dog's needs
• Adequate exercise that strengthens the cardiovascular system
• Regular vaccination and deworming to prevent infections
• An annual check-up at the vet to detect possible heart disease at an early stage
• Good dental hygiene to avoid bacterial infections
• A stress-free environment that keeps the dog relaxed and happy