Cats, like people, have only one very regular and normal heart rhythm. When the heart rhythm is very regular, the time interval between each heart beat is consistent, and the impulse signal sending point is usually located in the sinoatrial node of the heart, so it is called sinus rhythm. The heart rate speeds up during exercise and slows down during rest, but the time between each beat is not very different.

Arrhythmia refers to irregular heart rhythm. Cats with sinus arrhythmia have a heartbeat that alternates between fast and slow. Compared to normal sinus rhythm, the time between each heartbeat varies.

1. Cause

Diseases that can cause increased vagal tone in cats are similar to those in dogs, but vagal excitement rarely causes sinus arrhythmia in cats. Sinus arrhythmia in cats usually indicates a primary heart problem.

2. Clinical symptoms

Clinical symptoms related to heart disease may occur in cats with sinus arrhythmia. Affected cats may be quieter than usual and less likely to move. Breathing may be faster and harder than usual. Some cats with heart disease may also cough.

3. Diagnosis

The only test that can differentiate between sinus arrhythmia and other arrhythmias is the electrocardiogram (ECG). If sinus arrhythmia is found during ECG examination, whether further testing is/is not required depends on the patient's clinical symptoms. Possible tests include laboratory tests, chest/abdominal x-rays, and echocardiography (cats).

4. Treatment

There are usually no treatment recommendations for sinus arrhythmia in cats, but heart disease should be treated.

If the patient's arrhythmia is very severe, an ECG may be needed to monitor sinus arrhythmia. Regular ECG monitoring is the only way to determine that no other pathological rhythm is present. Subsequent follow-up visits, monitoring, and examinations will depend on the underlying cause of sinus arrhythmia.

Medication options for heart disease:

　1. Enalapril

Also known as ACE inhibitors, its function is to dilate blood vessels, adjust the activity of hormones that cause heart failure, and can effectively reduce the resistance of the heart to output blood flow. This type of drug has been successfully proven in many studies to effectively prolong the life of heart failure patients. Side effects of the drug include vomiting, diarrhea, hypotension, increased blood potassium concentration, or decreased kidney function.

　2. Furosemide

It is a type of diuretic that can accelerate the elimination of excess tissue fluid and body fluids in patients with heart failure. The dosage will vary depending on the patient's suitability and clinical response; but generally speaking, low doses are used in control chronic diseaseIt is necessary to use it. This drug is used to treat pulmonary edema and cough symptoms caused by heart failure, and the response is usually good. Drug side effects include excessive tissue fluid, loss of body fluids and electrolytes, especially potassium ions, which can ultimately lead to dehydration or weakness.

Dietary management of feline heart disease

1. Control sodium intake corresponding to each disease stage.

2. Be wary of loss of appetite. Maintain a proper weight.

3. Food must have high palatability, high energy density, and high protein.

4. Nutrients necessary to maintain heart health: EPA, DHA, L-arginine, anti-reactive oxygen species, vitamin B complex, magnesium, glycine, and L-carnitine.

The prognosis for cats with sinus arrhythmia depends on the type and severity of the primary heart disease. For feline heart disease, through early detection, treatment and dietary management, the development of the disease can be delayed and the current living situation can be improved. Cats should be given a physical examination at least once a year, and elderly cats can be increased to twice a year. Some chronic diseases can be detected early, so that scientific management can delay aging. Don’t assume “this is a normal geriatric disease” and consult your veterinarian if there are any worrying changes in symptoms.