IS YOUR DOG AT RISK FOR HEART DISEASE?

Dog Breeds at Risk for Heart Disease

OVERVIEW OF CONGESTIVE HEART FAILURE (CHF) AND HEART DISEASE

Congestive heart failure (CHF) occurs when there is a heart abnormality leading to the failure of the heart to pump enough blood to meet the body’s needs. CHF is not a specific disease – it is a condition in which congestion (fluid accumulation), decreased blood flow to the body, and/or abnormally low blood pressure arise as the final consequence of severe heart disease.

Heart disease refers to a variety of conditions that involve narrowed or blocked blood vessels. Heart disease is a common problem in dogs and can be caused by a number of underlying diseases including:

• Heart valve degeneration
• Heart muscle disease
• Irregular heart rate and rhythm (arrhythmia)

Heart disease can be present without ever leading to CHF. However, CHF can only occur in the presence of heart disease because it is a result of severe heart disease.

Congestive heart failure (CHF) is a severe heart disease that refers to the heart’s inability to pump adequate blood to the body. There are many causes of CHF in dogs. The two common causes are:

• Mitral Valve Disease (MVD) is the most common cause of canine CHF.
• Dilated cardiomyopathy (DCM) is the second most common cause of canine CHF.

DCM (usually in smaller breeds) and MVD (usually in larger breeds) are the most common inherited heart diseases seen in dogs.

Mitral Valve Disease (MVD)

Mitral Valve Disease (MVD) occurs when damaged and thickened valves develop within the heart of dogs. If the valves fail to close completely when the heart contracts, blood moves forward but some leaks backward. Fluid accumulates when the heart fails to pump enough blood to the body and instead the blood is transmitted backward from the heart to the lung or body. Cardiac function and circulation are then hindered.

Dilated Cardiomyopathy (DCM)

With this disease the heart muscle becomes weak and large, preventing it from pumping blood efficiently. This causes decreased cardiac output and tissue perfusion.

COMMON CLINICAL SIGNS OF CHF:

In the early stages, signs are usually subclinical (symptoms are not obvious yet). This phase can last months or years. MVD generally progresses slowly, but DCM can have a quick onset and progresses rapidly. Both eventually lead to CHF. As either progresses, common clinical signs may include:

• Persistent coughing, when at rest or sleeping, accompanied by difficulty breathing due mainly to the accumulation of fluid in the lungs (pulmonary edema). Irritation can induce a cough since the enlarged heart pushes against the trachea.
• Fatigue – dogs with CHF may tire out more easily and have reduced stamina.
• Lethargy – they do not engage in playing or walking as they once did.
• Persistent loss of appetite, a swollen belly, and pale or bluish gums.
• Generalized weight loss and muscle wasting due to the effects of CHF on other body systems.
• Fainting spells.
• Difficulty sleeping, especially fordogs who sleep on their sides.

BREEDS PREDISPOSED TO HEART DISEASE

The following breeds are at higher risk for heart disease:

1. Spaniels

The prevalence of MVD in Cavalier King Charles Spaniels is about 20 times that of other breeds. The onset of the disease is usually indicated by a heart murmur.

2. Dachshunds

Valve regurgitation happens when any of the four valves (tricuspid-, pulmonic-, mitral- or aortic valve) become leaky. Dachshunds often develop a murmur and eventually MVD from a leaking mitral valve.

3. Dobermans

DCM is a common disease in (especially male) Doberman pinschers. When the left ventricle enlarges and ceases functioning correctly, life-threatening arrhythmias (heart rhythm problems) may develop. Apart from veterinarian visits every six months, annual cardiologist screenings should also be considered.

4. Retrievers

Golden retrievers are prone to aortic stenosis, a serious valve disease problem. The aortic valve doesn’t develop properly in the womb and once born, the heart muscle thickens. From birth onwards, veterinarians should listen for a heart murmur.

5. Poodles

Middle-aged and senior miniature and toy poodles are at risk for MVD which can trigger heart failure. It’s crucial to catch the disease early so a treatment plan can be followed.

6. Schnauzers

Fainting episodes in miniature schnauzers, particularly in adult females, can be caused by sick sinus syndrome (SSS) which is a group of arrhythmias. Basically, the heart’s natural pacemaker (sinus node) doesn’t work properly. Other names for SSS include sinus node disease or sinus node dysfunction.

7. Boxers

Boxers are predisposed to a genetic heart disease by the name of arrhythmogenic right ventricular cardiomyopathy (ARVC) that can cause life-threatening heart rhythm abnormality.

If your dog is a member of one of these breeds, speak with your veterinarian about signs and symptoms to watch out for and how to slow down the progression of the disease. Annual veterinary visits may not be sufficient and should probably be increased to every six months so that possible conditions can be diagnosed or monitored before they get worse. Weight management is also important to help ensure the heart doesn’t work harder than it has to.