Wolff-Parkinson-White Syndrome in Cats

Wolff-Parkinson-White syndrome may not cause any problems for your cat. However, it typically leads to life-threatening heart problems in the future, especially in cases associated with hypertrophic cardiomyopathy. If you suspect your cat has Wolff-Parkinson-White syndrome, you should take it to the vet immediately.

Wolff-Parkinson-White syndrome in cats is a rare heart disease that is characterized by ventricular preexcitation. This condition occurs when electric impulses in the sinoatrial node – the “pacemaker” in the heart – prematurely activate the ventricles of the heart without following the proper conduction pathway.  Wolff-Parkinson-White syndrome is often a congenital defect in cats, meaning that it is present from birth. The condition can also be associated with hypertrophic cardiomyopathy, a condition in which the walls of the ventricles in the heart become thickened, decreasing cardiovascular efficiency.

Cats with ventricular pre-excitation may not show any symptoms at all. You should seek immediate veterinary attention as soon as you notice any of the following symptoms, which can be indicative of a more serious underlying condition:

• Rapid heart rate
• Collapse

Signs of heart failure include:

• Shallow or difficult breathing
• Open-mouthed breathing
• Lethargy and weakness

One of the primary causes of Wolff-Parkinson-White syndrome in cats is congenital heart defect or disease. While no breed, sex, or age predispositions have been identified for Wolff-Parkinson-White syndrome in particular, certain breeds have a higher risk for developing congenital and acquired heart disease, including Maine Coons, Ragdolls, and Persians.

Another cause of Wolff-Parkinson-White syndrome is acquired hypertrophic cardiomyopathy, the most commonly diagnosed cardiomyopathy condition. An acquired condition is one that develops after fetal development has concluded. There is strong evidence that hypertrophic cardiomyopathy has a link to genetics. Hypertrophic cardiomyopathy can lead to congestive heart failure later in life, so it should be addressed as soon as possible in order to secure the best prognosis.

Your vet will first conduct a thorough physical examination. Always tell your vet how long your cat has been suffering from symptoms, and inform them of any previous history of collapse or heart conditions. Standard diagnostic tests, including blood count, blood analysis, and urinalysis, will return normal results. The only test that will confirm the definitive diagnosis is an ECG. Signs of heart disease and defect will be evident on the ECG. Additional testing may be utilized if other underlying conditions or causes are suspected.

Little information exists on treating Wolff-Parkinson-White syndrome specifically. The primary objective of treatment is to manage symptoms rather than to cure the underlying condition or repair the congenital defect. Treatment may vary depending on whether or not underlying heart disease or other heart conditions are present. Your vet will be able to advise you on a treatment plan based on your cat’s specific needs.

There is currently no cure for the congenital defect responsible for Wolff-Parkinson-White syndrome or hypertrophic cardiomyopathy. Your vet will typically prescribe medications to manage individual symptoms rather than to cure the condition. Medications can help prevent the accumulation of fluid, control the heart rate, reduce heart murmurs, and prevent the formation of blood clots.  In cats that are seriously ill, medication via injection may be required. Additional treatment methods may be recommended on an individual basis.

Recovery and prognosis may vary depending on the symptoms, underlying conditions, and treatment methods utilized. In cats with congenital defects and no underlying conditions, the prognosis may be excellent for several years. The prognosis for cats with acquired hypertrophic cardiomyopathy may be guarded. However, Wolff-Parkinson-White syndrome that is managed with medication can greatly improve your cat’s quality of life and prognosis.

On the return home, you should make sure your cat has a comfortable place to rest during the recovery period. You may want to limit your cat’s outdoor activity during the recovery period so they don’t overexert themselves and cause further damage to their heart.

You should closely monitor your cat’s breathing, especially during rest or sleep. Keeping a daily log can help you recognize identify problems. Count how many breaths your cat takes over six seconds, and multiply that number by ten to get their respiratory rate per minute. Healthy cats have a resting respiratory rate lower than 40. If your cat has a rate that is consistently greater than this, or if it is exerting significant effort to breathe normally, contact your vet immediately.

Your vet will typically schedule follow-up appointments as needed to monitor heart function. During these appointments, your vet will take an ECG to ensure heart function. If your cat requires drug therapy via injection, your vet can advise you on follow-up appointments to administer them.

If your cat loses limb function, you should contact your vet immediately, as this can be a sign that blood clots are forming.