Cardiac disease is relatively frequent in ferrets presented to clinics and is commonly seen in middle-aged and older individuals. Generally, such individuals are over three years of age. Ferret cardiac disease is seen in both sexes, with seemingly equal gender distribution.
Symptoms of cardiac disease in ferrets present much as they would in dogs and cats; however, a particularly common sign in ferrets is hindlimb weakness. Therefore, cardiac disease should always be on the differential diagnosis list when an individual is presented to the clinic with this sign.
As with all diagnoses, a thorough patient history should be taken. Cardiac disease in ferrets can include a history of symptoms such as hypothermia, lethargy, exercise reluctance, weight loss, anorexia, coughing and, of course, the aforementioned weakness in the hindlimbs. These symptoms can be subtle in nature and may not be acute in the history provided by the owner.
On physical examination, evidence of pale or cyanotic mucous membranes, a delayed capillary refill time and/or an irregular pulse may be particularly indicative of heart disease. Further, the presence of a heart murmur on auscultation or cardiomegaly revealed by radiology is also indicative of cardiac disease. The lungs should also be auscultated to identify any crackles or sounds suggestive of pleural effusion or oedema, and the abdomen palpated to identify evidence of ascites.
Even though a suspected diagnosis of cardiac disease can be made based on clinical examination and medical history alone, further testing is often required to definitively confirm the presence and type of cardiac disease.
Though a suspected diagnosis of cardiac disease can be made based on clinical examination […], further testing is often required to definitively confirm the presence and type of cardiac disease
Radiography is the most commonly viable diagnostic tool for cardiac disease in ferrets; two-view thoracic radiographs can help when diagnosing cardiac disease and congestive heart failure (CHF).
The whole thorax should be included in the images as the anatomy of a ferret thorax differs from that of a cat or a dog. In particular, the heart is more globoid and located between the sixth and eighth intercostal spaces.
In the case of heart disease, an enlarged cardiac silhouette, tracheal elevation and increased sternal contact in the lateral view may be evident. The heart may be widened and will fill up more thoracic space in a ventrodorsal view.
Ultrasonography and echocardiography
Ultrasonography is a very helpful tool when identifying abnormalities of the heart and can be used to identify any pleural or abdominal effusion, as well as splenomegaly and hepatomegaly. Sedation is often preferred when performing this procedure as the patient is required to lie in lateral recumbency for a prolonged duration of time.
Echocardiography is useful to study cardiac size, the contractility of the heart and the functionality of the valves. The additional use of Doppler echocardiography can provide further information about blood flow and turbulence as well as valvular regurgitation.
Electrocardiography (ECG) is mostly used on ferrets with suspected abnormal rhythm and heart rate. It can be very helpful in diagnosing cardiac chamber enlargement and pericardial and pleural effusion (Bone et al., 1988).
ECG is performed with the animal in both left and right recumbency.
Common cardiac diseases in ferrets
There are multiple cardiac conditions and diseases that can affect ferrets, so diagnosing the type of disease is crucial to allow appropriate treatment options to be provided.
There are multiple cardiac conditions and diseases that can affect ferrets, so diagnosing the type of disease is crucial to allow appropriate treatment options to be provided
Below are some of the common cardiac diseases found in ferrets:
- Dilated cardiomyopathy is the most common cardiac condition reported in ferrets. It is described as a dilated left or right ventricle with systolic dysfunction. Treatment includes oxygen, diuretics (such as furosemide) and thoracocentesis if effusion is present. ACE-inhibitors such as pimobendan and/or digoxin can be added to the treatment protocol if deemed necessary
- Congenital heart disease has been diagnosed in animals up to six years old (van Zeeland and Schoemaker, 2022). Mild congenital heart disease may not require any treatment
- Hypertrophic cardiomyopathy involves concentric hypertrophy of the left ventricular wall and interventricular septum. In this case, beta-blockers are the treatment of choice (ie propranolol) alongside calcium channel blockers
- Valvular heart disease is frequently diagnosed in middle-aged and older ferrets and can occasionally be auscultated as a heart murmur. Often this condition will be associated with CHF, and treatment with a supplementation of diuretics, pimobendan and/or digoxin when necessary is advised
- Myocarditis is described as the infiltration of the myocardium with inflammatory cells. It can be of bacterial or nonbacterial origin. Antibiotics can be used for treatment in the first case, and symptomatic treatment is also recommended
- Heartworm disease is caused by infection with Dirofilaria immitis, which is a parasite hosted and transmitted by mosquito bites. Ivermectin is the recommended treatment for microfilaraemia, but additional medications can be implemented as adulticides
Hospitalisation of a ferret patient with severe cardiac disease requires the same process as any other species of small mammal. The provision of oxygenation therapy is often required to support the body – particularly the oxygenation of the heart tissue to maintain function. Maintaining the appropriate environmental temperature will further reduce any strain on the body from environmental stressors.
Reducing stress is highly important for patients with severe cardiac disease, so appropriate handling, limiting medications and providing appropriate food sources, etc, are paramount
Reducing stress is highly important for patients with severe cardiac disease, so appropriate handling, limiting medications and providing appropriate food sources, etc, are paramount. While intravenous access is often ideal for the provision of fluid therapy and medications, as well as emergency drugs should the patient deteriorate, the requirement of “need versus stress” must always be considered before placement.
Close monitoring of the patient’s behaviour, vitals and actions is always important; however, particular attention should be paid to ferret patients that have just started a new medication or have an increased dosage. This is especially true for medications such as ACE inhibitors, as ferrets are sensitive to the hypotensive nature of these drugs. The effects of these drugs, while known, should be fully explained to the owner as all the medications commonly used in the treatment of the cardiac patient are off-label and have been extrapolated from dog and cat treatments.
Particular attention should be paid to ferret patients that have just started a new medication or have an increased dosage
The presence, severity and type of cardiac disease in ferrets varies from individual to individual. Unfortunately, cardiac disease can quickly deteriorate from mild to severe even in a patient otherwise seemingly stable in its symptoms. Owner compliance and commitment is often one of the most important factors in the treatment of a ferret with cardiac disease, and it is through their dedication that a patient’s outcome can be determined.