Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

Arrhythmogenic Right Ventricular Cardiomyopathy is a disease where severe rhythm disturbances occur, and in some cases, the heart quits pumping normally and becomes enlarged and flabby.

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Disease Info

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

Arrhythmogenic Right Ventricular Cardiomyopathy


  • DEFINITION (What it is):
    • Arrhythmogenic Right Ventricular Cardiomyopathy is a disease where severe rhythm disturbances occur, and in some cases, the heart quits pumping normally and becomes enlarged and flabby.
  • EPIDEMIOLOGY (Who gets it):
    • Arrhythmogenic Right Ventricular Cardiomyopathy is a disease of Boxers, and can also affects other breeds occasionally
      • Average age of onset is 6 years of age
      • Some pets will get this disease much younger, or much older
    • It is also seen occasionally in cats.


  • CAUSE:
    • In Boxers, there has genetic component with one gene abnormality identified
      • Part of the striatin gene is missing (deleted), and this affects parts of the structure of the heart
      • This gene has variable penetrance (affects the pet based how many copies of the gene are present)
        • If there is only one copy affected, then there is less disease than if there are both copies of the gene affected
      • This gene can be tested for at North Carolina State University
    • Since in humans, there are 8 genes with 141 mutations identified, it is likely that there are other genes involved in canine ARVC
    • There may be other causes in other cases, like viral infection or environmental causes
  • CLINICAL SIGNS:
    • Clinical signs we see
      • None (occult arrhythmogenic right ventricular cardiomyopathy)  with arrhythmias picked up on routine examination
      • Collapse or fainting, called syncope- the most common presenting sign)
      • Signs of congestive heart failure
        • Increased breathing rate (> 30-35 breaths per minute) See our Resting Breathing Rates page
        • Coughing
        • Exercise intolerance or weakness
        • Loss of appetite
        • Weight loss
        • Distended belly
      • Sudden death- this is often the cause of sudden death in Boxers
    • Signs are due to two main reasons, there are abnormal heart beats present (most common in ARVC) or the heart muscle becomes weak and flabby, or both
      • Dogs with significant arrhythmias can faint (with exercise or excitement or even at rest), or be at risk for sudden death with a heart attack
      • Because the heart is not pumping blood forward effectively, causes blood to back up and force fluid into either the lungs or into body cavities.
        • If the ventricles do not pump blood forward properly, the ventricles and atria get enlarged, and pressure builds up in the left or right atrium. Blood then ‘backs up’, and causes fluid in the lungs or body cavities to accumulate.
          • Fluid in the lungs is called left congestive heart failure (congestion) or pulmonary edema.
            • animals with pulmonary edema breath more rapidly and cough due to the fluid, and cannot exercise well.
          • Fluid in the body cavities is called right congestive heart failure (congestion)
            • Fluid in the chest is called pleural effusion
              • Animals with pleural effusion breath heavily and cannot exercise
            • Fluid in the abdomen is called ascites
              • Animals with ascites often do not eat well
  • DIAGNOSIS:
  • Holter Monitor
    • This is the best way to test for ARVC, and for screening
      • This should be started at 3 years and repeated yearly
        • a negative result in one year does not predict if there will not be significant arrhythmias in another year
    • An 24 hour electrocardiogram (Holter monitor) may be required to check for very intermittent rhythm disturbances where we cannot detect significant rhythm disturbances in the office
    • Your pet wears a backpack system at home, and we want you to perform normal activities
    • This will be recommended if a pet is fainting


  • Echocardiography
    • An echocardiogram (or heart ultrasound) is used to look within the heart, confirm the diagnosis, and to look for other problems within the heart that might confound therapy.
    • An echocardiogram is the definitive test for diagnosing the muscle form of arrhythmogenic right ventricular cardiomyopathy
    • Echocardiograms do not show congestive heart failure, so have some limitations for following the disease.
    • If the disease is in the early stages, where heart size or function is very mildly affected (occult arrhythmogenic right ventricular cardiomyopathy)
      • Serial echocardiograms will be necessary
    • Since Choice has all the veterinary and breed normals published to compare values to (through our EchoVet software), we can analyze subtle abnormalities much more carefully


  • Radiography
    • X-rays (radiographs) let us see the heart size (but not inside the heart), and also let us evaluate the lungs (which an echocardiogram cannot perform)
    • Radiographs show how large the heart is in the chest and how it is enlarging with time, and also show congestive heart failure (pulmonary edema) or other lung problems.
    • Radiographs are often repeated with time to assess response to therapy.


  • Electrocardiography
    • An electrocardiogram (EKG or ECG) is very useful to check for rhythm disturbances and may be repeated to assess response to certain medications.


  • Blood Pressure
    • A blood pressure is often useful, since the heart is not pumping blood effectively, and blood pressure can be low
    • Some heart medications can lower blood pressure, and cause pets to be weaker on their medications


  • Laboratory Testing
    • Genetic testing through North Carolina State University can tell whether the striatin gene is affected and whether one gene (hetrozygous) or two genes (homozygous) are affected.
      • Positive testing may indicate the severity of arrhythmias one might anticipate
      • It will not tell when arrhythmias might develop
        • It is important to remember there are other causes of arrhythmias, and also probably that there are other genes affected, so genetic testing is generally performed in a breeding situation, not in a clinical situation
    • Since heart medications can affect other body systems (especially the kidneys), laboratory testing is often essential
    • Labwork is very important, because hearts with disease do not handle water loads very well , but kidneys require water load to maintain function.
    • Usually, there is a wide area to work within where the heart and the kidneys are both happy, but if kidney function is marginal, kidney failure can occur.
    • We may also need to evaluate for other disease that may be making your pet feel ill


  • TREATMENT:
    • Therapy is medical in nature.
      • Heart transplants are not done in animals.
      • The goals of therapy are to maintain your pet out of congestive heart failure for as long as possible on a minimum of medication, for them to feel well and to be playful (although they usually cannot exercise), and for them to eat well.
        • We can affect the heart in a multitude of ways
          • Diuretics (furosemide, spironolactone, hydrochlorthiazide, torsamide)
            • Decrease the amount of fluids that the heart has to handle
          • Inodilators (pimobendan)
            • Make the heart pump blood forward more effectively
          • Vasodilators (amlodipine, benazepril, enalapril, hydralazine, others)
            • decrease blood pressure and make it easier for the heart to pump effectively
          • Hormone system control (benazepril, enalapril, spironolactone)
            • In heart disease, circulating hormones get activated that make the disease progress
              • In some cases, decreasing these circulating hormones can improve survival
          • Rhythm disturbance control (digoxin, diltiazem, mexilitine, sotalol, others)
            • Since many pets with arrhythmogenic right ventricular cardiomyopathy will have significant heart rhythm disturbances, it is not uncommon to have to treat these disturbances
          • Nutritional Supplements (Taurine, Carnitine, Omega 3 Fatty Acids)
            • There are some nutritional supplements that may be effective in some breeds, such as Taurine or Carnitine.
            • Coenzyme Q has not been shown to be useful in this disease.
          • Diet
            • See our Food and Diets Information page
              • A severely restricted salt diet such as “Heart diet or H/D” is often not eaten well at all by animals
              • It is more important that your pet eat and eat well, than to stick to the salt restricted diet, even if they won’t eat it.
                • The medications are powerful, and will usually work even if your pet is on regular food.
              • Do not give high salt items such as pork, lunch meats, salted popcorn or high-salt treats.
          • Exercise
            • Exercise is usually moderately restricted
              • They can exercise normally if they want to
              • Restrict the amount or length of exercise
                • Restrict long ball or frisbee throwing, swimming
                • Climbing 14er’s may not be tolerated, and walking in the flats is often better
  • PROGNOSIS (What’s going to happen):
    • Occult arrhythmogenic right ventricular cardiomyopathy (before clinical signs occur)
      • with good care, many of these pets will live for 1-3 years before developing clinical signs
    • Clinical arrhythmogenic right ventricular cardiomyopathy (after clinical signs are present)
      • In Doberman pinschers, prognosis remains poor
        • many dogs will die either suddenly of a heart attack, or have recurrent, severe pulmonary edema (congestive heart failure fluid in the lungs)
      • In other breeds, with good care, many dogs will live more than 6-12 months
        • With good quality of life
  • FOLLOW UP CARE:
    • Monitoring
      • Monitoring at home consists of monitoring eating and activity, and to note breathing and coughing patterns. Because fluid in the lungs causes increased breathing rates as the first sign of congestive heart failure, noting breathing rates is very important. See our Resting Breathing Rates page
    • In the immediate short term, followup laboratory work and radiographs are often required to adjust medications
    • In the long term, followup every 2-4 months is generally performed
      • The testing performed often is case dependent
        • often depends on the signs you are seeing with your pet

Quick Info

DEFINITION (What it is): Arrhythmogenic Right Ventricular Cardiomyopathy is a disease where severe rhythm disturbances occur, and in some cases, the heart quits pumping normally and becomes enlarged and flabby
EPIDEMIOLOGY (Who gets it): ARVC is a disease of Boxers, and can also affects other breeds occasionally
CAUSE: In Boxers, there has genetic component with one gene abnormality identified
CLINICAL SIGNS: Collapse or fainting, called syncope- the most common presenting sign), signs of congestive heart failure
POSSIBLE DIAGNOSTICS: Holter Monitor, Echocardiography (heart ultrasound). Radiographs (x-rays). Electrocardiogram. Doppler Blood Pressure.
THERAPY: Therapy is medical in nature
PROGNOSIS: With just arrhythmias, many pets may live for many years. With heart muscle dysfunction, prognosis is quite poor
FOLLOW UP CARE: The testing performed often is case dependent