Arrythmogenic Right Ventricular Cardiomyopathy (ARVC) was formerly known as Boxer Cardiomyopathy.

The clinical course of ARVC is often quite sudden with no symptoms seen before the initial episode. Often the first sign that is seen is sudden death during exercise or even while sleeping.

Treatment for ARVC is anti-arrhythmic therapy often combined with diuretics and Angiotensin Converting Enzyme inhibitors (ACE inhibitors).

Life expectancies are extremely variable, but with medication and monitoring many pets enjoy years of quality life.

What is Arrythmogenic Right Ventricular Cardiomyopathy?

• Arrythmogenic Right Ventricular Cardiomyopathy (ARVC) was formerly known as Boxer Cardiomyopathy. ARVC is a genetic disease that runs in families and causes substantial illness and death in young dogs, especially boxers. It has been reported in humans and recently in cats too. The genetic defect is transmitted as an autosomal dominate trait. For this reason it is strongly recommended that dogs with this congenital defect not be breed.
• ARVC is a disease of the heart that causes arrhythmias (abnormal heart beats) beginning in the right ventricle of the heart. The arrhythmia present is a ventricular tachycardia with premature ventricular complexes. This means the ventricles are contracting too rapidly and out of sync with the rest of the heart. This causes a decrease in blood flow to the body and can lead to episodes of collapse, unconsciousness, and even death. In some cases the incidence of the premature heart beats was over 28,000 in a 24 hour period.

Clinical Signs

• The clinical course of ARVC is often quite sudden with no symptoms seen before the initial episode. Often the first sign that is seen is sudden death during exercise or even while sleeping. Other less severe signs that are often seen are syncope (collapse), exercise intolerance, and signs of right sided heart failure (see below).
• What could you see at home if your pet has Arrythmogenic Right Ventricular Cardiomyopathy?
  In the worst case scenario, the only sign you would see at home is sudden death. In less severe manifestation, you would see exercise intolerance, episodes of collapse, or possibly abdominal distention or swelling from fluid build-up.
• What could your veterinarian see at your regular exam? Some of the findings your veterinarian may see at a regular examination include elevated heart rate, abnormal heart beats, distension of the jugular vein, jugular pulses, dropped heart beats, enlarged liver, fluid in the abdomen, and/or weak pulses.

Diagnosis

• The diagnosis of ARVC is made by electrocardiography (ECG) and echocardiography (ultrasound of the heart). The diagnosis of ARVC is made with an initial ECG run by your veterinarian showing the conduction patterns of the heartbeats. An additional 24 hour ECG (Holter monitor) is then generally run to evaluate the extent of the disease and to monitor treatment. An echocardiogram is also performed to rule out other heart diseases that often accompany ARVC and to get a baseline for evaluating heart function.
• Recently research on ARVC has led to the use of other diagnostics including magnetic resonance imaging (MRI) and gene mapping. These diagnostics are still in the experimental phase, but may lead to earlier detection of ACVR and better prognostic indicators.

Treatment

• Treatment for ARVC is anti-arrhythmic therapy often combined with diuretics and Angiotensin Converting Enzyme inhibitors (ACE inhibitors). The anti-arrhythmic of choice is Sotalol. Furosemide (Lasix) and Enalapril are the most common diuretics and ACE inhibitors given.
• Sotalol is a beta-blocker and anti-arrhythmic that works on the heart muscle to decrease the number of heart beats, slowing the heart muscle down. Some common side effects of Sotalol are fatigue, dizziness, nausea, and bronchospasms (coughing).
• ACE inhibitors work indirectly by stopping the activation of an enzyme (angiotensin) that tells the body to save fluids. Stopping the activation of this enzyme decreases the amount of fluid the kidneys try and save thus decreasing total body fluid levels. Some common side effects from this medication are nausea, appetite loss, and diarrhea. This medication can also affect the kidneys so close monitoring of the kidney blood values by your veterinarian will be needed.
• Diuretics work directly by increasing the amount of urine the kidneys excrete thus lowering the bodies overall fluid volume. Some common side effects of diuretics include increased thirst and urination, nausea, and appetite loss. These medications can also affect the kidneys so close monitoring of the kidney blood values by your veterinarian will be needed.

Prognosis

• ARVC is a life long disease that will eventually lead to the death of your pet. Life expectancies are extremely variable, but with medication and monitoring many pets enjoy years of quality life. Unfortunately, the disease can also be so severe that sudden death occurs even with treatment.