Dilated Cardiomyopathy in Ferrets (Heart Failure, Congestive Heart Disease)

Dilated cardiomyopathy (DCM) is the most commonly reported cardiac disease in ferrets. It is characterized by the progressive loss of cardiac contractility, resulting in a dilated or enlarged heart. With this type of disease, the walls of the heart become thin and weak and unable to efficiently pump blood out into the general circulation. Affected ferrets may show no symptoms at all or they may become weak and collapse.

The cause of this condition in ferrets is unknown. In cats, a taurine (an amino acid) deficiency can lead to dilated cardiomyopathy but this does not seem to be the case in ferrets.

This is a disease usually occurs in older ferrets over four years of age. Both males and sfemales are susceptible. The risk of developing heart disease increases with age.

Ferrets with cardiomyopathy usually do not show symptoms at first, but in time can become quite sick from heart failure. Ferrets with heart failure are weak, have trouble breathing, and difficulty walking. Coughing is uncommon in ferrets with heart disease.

What To Watch For

• Rapid breathing
• Weakness, especially in the rear legs
• Increased sleeping

Diagnosis

The most important initial diagnostic test is a good physical examination with auscultation (stethoscope listening) of the heart. Ferrets with DCM usually have murmurs (abnormal heart sounds) and sometimes have arrhythmias or dropped beats. The lungs may sound wet from fluid build-up (edema or effusion). In addition, your veterinarian may recommend the following:

• Radiographs (X-ray's) of the chest. This allows visualization of the heart size and to check for fluid in and around the lungs. There are other diseases that can mimic heart failure (like cancer) and the radiograph can help differentiate among certain diseases in the chest.
• The echocardiogram or sonogram. This is a non-invasive test to determine what type of dysfunction the heart has and then help guide the clinician in the correct choice of heart medications and is usually done by a specialist. The shape, size, and actual movement of the heart and the valves can be measured with the echocardiogram. Follow-up echocardiograms can then be done at regular intervals to assess any further changes in the heart function. In outdoor ferrets in warm climates, heartworm disease can lead to heart failure and the echocardiogram may determine if this parasite is in the heart.
• EKG (or ECG). An electrocardiogram is much different from the echocardiogram. The EKG measures electrical impulses of the heart and is read-out as a linear pattern with upward and downward deflections on a rolling scroll of paper or heart monitor screen. This test is best for assessing rate and rhythm of the heart and is most useful in ferrets that have an irregular heartbeat.
• Blood testing. Ferrets with heart disease are typically older (geriatric) and may be suffering from more than one condition. It is important to know the health of the major organs like the liver or kidneys before starting certain heart medications. Basic blood testing includes a complete blood count (CBC) and a biochemistry panel.

Treatment

The drugs used most often in the treatment of DCM are Lasix®, Lanoxin®, and Enacard®. These are described below:

• Diuretics like furosemide (Lasix®) are used to reduce fluid in the lungs and to reduce water retention. Overdosage can lead to dehydration.
• Digoxin (Lanoxin®) is a heart medication that increases the ability of the heart muscle to contract, reduces the heart rate, and helps reduce certain types of arrhythmias. Overdosing can cause weakness, anorexia and irregular heartbeats.
• Vasodilators like enalapril (Enacard® or Vasotec®) reduce blood pressure and decrease the workload of the weakened heart. Some ferrets can become weak from this drug so the dose and frequency must be carefully monitored and adjusted on an individual basis. This should be used with caution in ferrets with kidney disease.

Home Care and Prevention

Optimal treatment requires a combination of home and professional veterinary care. Administer all medications as prescribed by your veterinarian. There are potential side effects of heart drugs and any change in your ferret's behavior should be reported. Watch for weakness, difficulty walking, and increased respiratory effort or rate.

It is important to maintain a healthy diet for your ferret and avoid too many table scraps or treats, especially those high in salt or sugar.

Because we really don't know what leads to heart disease in ferrets, it would be difficult to try to prevent this problem. However, because diet plays a role in the development of heart disease in some other species, it would be wise to use only a high quality ferret food from the start.