Valvular Heart Disease in Ferrets

Disease Summary

Alternative Names (Synonyms)

• Dilated Cardiomyopathy in Ferrets
• Hypertrophic Cardiomyopathy in Ferrets

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

• Non-bacteria thrombotic endocarditis is associated with aortic valve degeneration. (J213.12.w1, B631.26.w26)
• The cause of cardiomyopathy is unknown. (J213.12.w1)

Infective "Taxa"

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Non-infective agents

Physical agents

References

Disease Author

Major References / Reviews

Code and Title List

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

Clinical Characteristics

• Ferrets maybe be asymptomatic with valvular heart disease. (J213.12.w1, B631.26.w26)
• Clinical signs depend on the severity of the heart disease. (B602.6.1.w6A)
• Valvular heart disease may develop to congestive heart failure. (B631.26.w26)

General

• Weight loss. (B629.13.w13, B631.26.w26)
• Exercise intolerance. (J213.12.w1, B631.26.w26)
• Lethargy. (B629.13.w13, B631.26.w26)
• Inappetence. (B629.13.w13, B631.26.w26)
• Hypothermia. (B629.13.w13)
• Sometimes ascites. (B631.26.w26, J213.12.w1)

Cardiovascular

• Cyanotic mucous membranes. (J213.12.w1, B629.13.w13, B631.26.w26)
• Prolonged capillary refill time. (J213.12.w1, B629.13.w13, B631.26.w26)
• Jugular distension. (B629.13.w13)
• Femoral pulse deficits may occur with arrhymias. (B629.13.w13, B631.26.w26)
• Hyperdynamic femoral pulses may be noted with significant aortic regurgitation. (B602.6.1.w6A)
• On auscultation, a left atrical systolic murmur if mitral valve regurgitation is occurring, and a right parasternal  murmur if tricuspid regurgitation is occurring. (B602.6.1.w6A)

Respiratory

• Tachypnoea. (B631.26.w26)
• Dyspnoea. (J213.12.w1, B631.26.w26)
• Coughing or gagging. (B631.26.w26)
• Moist râles can be heard by auscultation. (J213.12.w1, B602.6.1.w6A)

Musculoskeletal

• Hind leg weakness. (J213.12.w1, B631.26.w26)
• Impaired movement of the hind limbs. (B629.13.w13)

Incubation

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Mortality / Morbidity

Morbidity

• Valvular heart disease is one of the most common heart diseases in ferrets. (J213.12.w1, B631.26.w26)
• Valvular heart disease is increasing in middle age to older ferrets. (B602.6.1.w6A, B629.13.w13)

Mortality

• The prognosis is affected by a variety of factors including coexisting disease, cardiac rhythm and renal function. (B602.6.1.w6A)
• The prognosis depends on the severity of the disease and is guarded to poor. (B629.13.w13)

Pathology

Gross pathology

• General:
  • Abdominal ascities (due to congestive heart failure). (J213.12.w1, B629.13.w13)
• Cardiac:
  • Thickening and shortening of the heart valves. (B232.12.w12, B629.13.w13)
    • At the free edge and base of valve leaflets, nodular opaque thickening and shortening. (J213.12.w1)
  • Atrial enlargement. (J213.12.w1, B232.12.w12, B629.13.w13)
  • Left atrial and ventricular dilation. (J213.12.w1)
• Respiratory:
  • Pleural effusion (due to congestive heart failure). (J213.12.w1)
  • Pulmonary oedema (due to congestive heart failure). (J213.12.w1, B602.6.1.w6A)
• Hepatic: Hepatomegaly (due to congestive heart failure). (J213.12.w1, B629.13.w13
• Splenic: Splenomegaly (due to congestive heart failure). (J213.12.w1, B629.13.w13)

Histopathology

• Myxomatous degeneration of the heart valves. (B629.13.w13)

Human Health Considerations

Disease has been reported in either the wild or in captivity in:

• Valvular heart disease is one of the most common heart diseases in ferrets. (B631.26.w26)

Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

• Mustela putorius furo

(List does not contain all other species groups affected by this disease)

Disease has been specifically reported in Free-ranging populations of:

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Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Host Species List

• --

(List does not contain all other species groups affected by this disease)

General Information on Environmental Factors/Events and Seasonality

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Regions / Countries where the Infectious Agent or Disease has been recorded

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Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

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General Information on Investigation / Diagnosis

• Diagnosis may be made with ultrasound and clinical signs. (B232.12.w12)

Auscultation

• A heart murmur is commonly detected in valvular heart disease. (J213.12.w1, B150.w4, B631.26.w26)
  • This can be heard along the left sternal border. (B150.w4, B602.6.1.w6A)
  • Diastolic murmur of aortic insufficiency may be heard, but this murmur is difficult to hear and rare. (B602.6.1.w6A, B631.26.w26)
  • Holosystolic murmur (J213.12.w1) can be heard over the left apical area and moist lung sounds. (B232.12.w12)
  • Right parasternal murmurs may be due to tricuspid valve insufficiency while left apical murmurs generally reflect the mitral valve. (J213.12.w1, B602.6.1.w6A)
• All or some of arrhythmias, gallop sounds, muffled heart and lung sounds, may be detected in ferrets with heart disease. (B631.26.w26)
  • Tachyarrhythmias. (J213.12.w1)

Radiography

• Radiography can help determine the size of the heart and help diagnose congestive heart failure. (J213.12.w1, B602.6.1.w6A)
  • In a healthy ferret:
    • The trachea and thoracic cavity are moderately long. (J213.12.w1)
    • The trachea is also bent slightly ventral. (J213.12.w1)
    • On a lateral radiograph the heart can appear elevated. (J213.12.w1)
• The right lateral view should allow for cardiac measurements. (J213.12.w1)
  • Measurements should be taken from the main stem bronchus to the apex. (J213.12.w1)
  • The short axis is measured across the long axis, at the level of the caudal vena cava. (J213.12.w1)
  • Measurements are taken form T5 to T8 and are generally 3.75 to 4.07 vertebrae in total. (J213.12.w1)
  • Another way to measure the heart is rib spaces. The right lateral short axis should be be 2.28 rib spaces, measured level with the caudal vena cava, in a normal ferret. (J213.12.w1)
• A rounded heart shadow, elevated trachea and pleural effusion may be present in heart disease, and increased contact between the heart shadow and the diaphragm or sternum may be seen. (J213.12.w1)
• Other radiographic signs are pulmonary oedema, venous congestion, and ascites. (J213.12.w1)
  • A patchy alveolar and interstitial pattern is seen in pulmonary oedema (indicative of congestive heart failure), particularly in the caudodorsal lung regions. (B602.6.1.w6A)
• Hepatomegaly and splenomegaly may be present with congestive heart failure. (J213.12.w1)
  • Note: splenomegaly may occur as a non-specific finding, particularly in older ferrets. (J213.12.w1)

Ultrasonography/Echocardiography

• The ferret should be examined in dorsal or lateral recumbency and sedation is not recommended, as this could potentially interfere with the results. (J213.12.w1)
  • Valvular heart disease is best detected by two-dimensional imaging with a Doppler probe. (B150.w4, B602.6.1.w6A, B629.13.w13)
  • M-mode measurements allow assessment of indices of systolic function, chamber dimensions and wall thickness. (J213.12.w1)
  • Note: care should be taken to make sure the ferret is hydrated, as this can change readings of wall thickness and lead to an incorrect diagnosis. (J213.12.w1)
  • Characteristically, ultrasonography will reveal heart valve thickening and increased echogenicity; this appears to affect the mitral valve most commonly. (J213.12.w1)
  • Regurgitation through the mitral or tricuspid valves is best detected with colour flow doppler or pulse wave doppler. (J213.12.w1)
    • There may be mitral valve regurgitation (B150.w4, B631.26.w26, J213.12.w1) and thickening. (B631.26.w26)
    • Less commonly, tricuspid and pulmonic valve regurgitation and thickening may be present. (B631.26.w26)
    • Regurgitation is often substantial in ferrets with valvular heart disease. (J213.12.w1)
    • Aortic valve thickening and moderate to severe regurgitation sometimes occurs. (B631.26.w26) 
    • Note:  
      • Mild aortic insufficiency (mild valvular regurgitation) is commonly found in ferrets and may be normal. (B150.w4, B602.6.1.w6A, B631.26.w26, J213.12.w1)
      • Mild regurgitation through other valves also may be a normal finding in ferrets. (J213.12.w1)
  • The left ventricular wall is of normal thickness. (B602.6.1.w6A)
  • The left ventricle shows an increased diastolic dimension while the systolic dimension is normal (B602.6.1.w6A, J213.12.w1)  or may be slightly increased (J213.12.w1); fractional shortening is normal (B602.6.1.w6A, J213.12.w1) to increased. (J213.12.w1) 

Electrocardiography (ECG)

• This may assist in diagnosing abnormal rhythms and electrical conduction disturbances. (J213.12.w1)
• Place the ferret in lateral recumbency for an ECG. (B631.26.w26)
• Moist swabs can be used to soften attachment of the clamps to the ferret. (B631.26.w26)
  • The teeth on the clamps should also be filed smooth, to prevent trauma to the ferrets skin. (B629.13.w13, B631.26.w26)
• On normal ferret ECGs on lead II, small P waves, large R waves (J213.12.w1), short QT intervals and elevated ST segments, should be present. (B629.13.w13)
  • Abnormal ECGs include, sinus bradycardia, tachycardia, atrial or ventricular premature complexes, tall and wide QRS complexes and depression of the ST segment. (B629.13.w13)
• Atrial arrhythmias. (B602.6.1.w6A)

Blood pressure measurement

• Doppler and a pressure cuff can be used to take blood pressure readings. (J213.12.w1)
• The digital branch of the tibial artery, the tail artery or pedal artery can be used. (J213.12.w1)
• A neonatal cuff should be used - its width it should be 40% of the circumference of the extremity on which it is being places, and the smallest available size may be too large, resulting in underestimation of blood pressure. (J213.12.w1)
• This is usually carried out under isoflurane anaesthesia. (J213.12.w1)
• The normal ferret ranges are systolic pressure 140 to 164 mm Hg and diastolic 110 to 125 mm Hg (normal ranges may vary depending on the references used). (J213.12.w1) 

Blood sampling

• A serum biochemistry profile and complete blood count can highlight concurrent diseases. (B629.13.w13)

Thoracocentesis

• In cases of pleural effusion and thoracic fluid, cytology should be performed to rule out other diseases. (J213.12.w1)

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Clinical Pathology of Ferrets
• Imaging in Ferret Diagnosis and Treatment
• Necropsy of Mammals
• Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation
• Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment
• Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

Similar Diseases (Differential Diagnosis)

• Dilated Cardiomyopathy in Ferrets
• Hypertrophic cardiomyopathy in Ferrets
• Heartworm Infection

Specific Medical Treatment

Treatment is recommended in congestive heart failure or if the heart is enlarged. (B602.6.1.w6A)

• Treatment for general heart disease (congestive heart failure):
  • Furosemide (B150.w4) (diuretic). (B602.6.1.w6A, B232.12.w12)
    • 2-4 mg/kg intramuscularly or intravenously every eight to twelve hours initially and then 1-2 mg/kg orally every twelve hours for maintenance. (P120.2006.w4)
    • Furosemide can be given at 2.5-4 mg/kg every eight to twelve hours. (B629.13.w13)
    • Furosemide 2-3 mg/kg intramuscularly or intravenously every eight to twelve hours. 1-2 mg/kg orally every twelve hours for long term treatment. (J213.12.w1)
    • Renal values should be monitored when the ferret is on furosemide. (B602.6.1.w6A)
  • Nitroglycerine (venodilator) 2% ointment/paste. (P120.2006.w4)
    • This cream can be placed on hairless areas of the skin (shaved inner thigh or pinna), every twelve to twenty four hours. (B602.6.1.w6A, B629.13.w13); one-sixteenth to one-eighth of an inch can be used every twenty four hours. (J213.12.w1) 
    • Note: Care should be taken with dosing to avoid hypotension. (B631.26.w26)
  • ACE inhibitors (B602.6.1.w6A, B232.12.w12), such as enalapril, captopril or benazapril, can be used as oral medication. (P120.2006.w4)
    • This will increase the cardiac output and decrease oedema. (B629.13.w13)
    • Enalapril (B150.w4) 0.25-0.5 mg/kg orally every forty eight hours initially (J213.12.w1) and then increase to twice daily. (P120.2006.w4)
    • 1 mg tablet is available for oral medication. A quarter or half a tablet can be given depending the weight of the ferret. (P120.2006.w4)
    • Note: This requires close monitoring, as ACE inhibitors have hypotensive effects on ferrets, especially with dehydrated or renally compromised animals. (J213.12.w1, B629.13.w13)
    • Renal patients may benefit from being on benazapril, instead of enalapril. (P120.2006.w4)
  • Digoxin can be used later, if systolic function becomes diminished. (B150.w4) used for supraventricular arrhythmias or impairment of systolic function. (B232.12.w12)
    • Digoxin is given to stabilise heart rate and control supraventricular arrhythmias, also for its positive inotropic effect (B602.6.1.w6A)
    •  0.01 mg/kg orally every twenty four hours initially (B602.6.1.w6A, B629.13.w13) and increased to every twelve hours or decreased to once every other day, depending on the ferret's condition. (B629.13.w13)
      • Serum digoxin levels should be monitored every eight hours post treatment. Therapeutic levels that should be reached are 0.8-2.0 ng/mL. (B629.13.w13)
    • Note: The ferret should be monitored for side affects, such as inappetence, vomiting and diarrhoea and arrhythmias. Digoxin treatment should be avoided in ferrets with hypokalaemia or azotaemia (nitrogenous substances in the blood), or if they have frequent ventricular arrhythmias. (B629.13.w13)
  • Pimobendan (Vetmedin, Boehringer Ingelheim Limited) 0.5 mg/kg every twelve hours orally, in the treatment of mitral valve disease. (J213.12.w1)

Note: The prognosis depends on the severity of the disease and is guarded to poor. (B629.13.w13)

• Treatment and Care
• Oral Medication and Syringe Feeding of Ferrets

General Nursing and Surgical Techniques

• Oxygen should be given to the ferret in cases of dyspnoea. (B629.13.w13)
• Activity should be restricted. (B629.13.w13)
• A low salt diet is recommended. (B629.13.w13)
• Abdominocentesis and thoracocentesis can be performed during long term treatment. (J213.12.w1)

• Treatment and Care

Preventative Measures

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• Preventative Medicine for Mammals

Environmental and Population Control Measures

Ferrets

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• Environmental and Population Management - General