ABSTRACT

Cardiac disease in pet ferrets is common and includes dilated cardiomyopathy, arrhythmias, and acquired valvular disease. Clinical presentation of cardiac disease in ferrets may be similar to dog or cats, although hind limb weakness may be a prominent feature. Radiography, ECG, and ultrasound are all useful tools in the diagnosis of cardiac disease in ferrets. Therapeutics for cardiac disease in ferrets is based on recommendations for dogs and cats. The prognosis for cardiac disease in ferrets varies from fair to guarded, depending on underlying disease.

Cardiac disease is common in pet ferrets (Mustela putorius furo).^1–5 It is reasonable to expect the full spectrum of cardiac diseases in ferrets found in small companion mammal practice. Dilated cardiomyopathy (DCM), arrhythmias, and acquired valvular disease are the most common heart diseases this author sees in practice. Congenital defects in heart development are seldom reported, but atrial septal defect and patent ductus arteriosus occur. A variety of inflammatory myocardial diseases, including Toxoplasmosis, Aleutian disease virus, and fungal and bacterial sepsis, are rarely diagnosed in practice. Neoplasia of the heart is rarely reported, with lymphosarcoma being most common. Pericardial fluid from chyle or neoplasia (lymphosarcoma) occurs with few reports in the literature. Nonbacterial thrombotic endocarditis is associated with myxomatous aortic valve degeneration.⁶ Ferrets are definitive hosts for Dirofilaria immitus, and heartworm disease should be on the differential list in endemic areas.

Clinical presentation of cardiac disease in the ferret ranges from an asymptomatic, incidental finding to fulminant heart failure.^1–4 Ferrets with clinical heart disease are generally weak, exercise intolerant, dyspneic, and often have pale or cyanotic mucus membranes with prolonged capillary refill time. Occasionally ferrets cough from pulmonary edema, heartworm infections, or main stem bronchi compression from an enlarged heart. Rear leg weakness can be seen and is thought to be associated with general weakness or from congestive heart failure (CHF). Left- and right-sided CHF can produce thoracic effusions, moist rales, ascites, or organomegaly. Respiratory rate may be increased, especially if thoracic effusions are present. Heart murmurs are common with DCM and valve insufficiency but are uncommon in hypertrophic cardiomyopathy (HCM). Clinicians may have difficulty determining the origin of heart murmurs. Often only a nonspecific left parasternal systolic murmur is heard. Holosystolic murmurs are most often caused by valvular regurgitation. Left apical murmurs are usually mitral valve, and right parasternal murmurs may be tricuspid valve insufficiency. Heart murmurs vary not only in location and duration but also in intensity. Anemia can cause low intensity variable location murmurs in ferrets because of low fluid viscosity. The normal heart rate is between 180 and 250 beats per minute (bpm). Sinus arrhythmia may produce a pronounced decrease in heart rate with occasional pauses auscultated; this should not be confused with pathologic bradycardia. Increased heart rate (> 250 bpm) and gallop rhythms (third and fourth heart sounds auscultated) are common with DCM and HCM, respectively. Tachyarrhythmias can be seen with either form of cardiomyopathy or acquired valvular disease. Arrhythmias caused by premature ventricular contractions or second- or third-degree heart blocks may be the only physical examination findings and should be evaluated thoroughly to determine their cause and significance. Sinus rhythm, sinus tachycardia, and bradycardia caused by second-degree heart block can be seen in normal ferrets, ferrets with asymptomatic cardiac disease, and ferrets with clinical cardiac disease.