Canine Dilated Cardiomyopathy
Cardiomyopathy is generally seen in the larger breeds of dogs. Small to medium sized dogs tend to get valve disease rather than cardiomyopathy.
The most common form in large dog breeds is called Dilated Cardiomyopathy.
Boxers have there own version called Boxer Cardiomyopathy which has recently been renamed Arrythmogenic Right Ventricular Cardiomyopathy (ARVC)
As in humans, this form of heart disease presents with an enlarged heart with thin walls. The walls are so thin that they are incapable of pumping blood out of the heart in an effective manner.
- Decreased exercise tolerance
- Rapid heart and respiratory rates
- Weak pulse
- Poor gum colour and refill time
- Collapse and/or feinting
- Ascites (fluid buildup in the abdomen)
- Jugular pulse
- Weight loss
- General heart enlargement (cardiomegaly)
- Enlarged left atrium
- Dilated pulmonary arteries and veins
- Pulmonary oedema
- Elevated trachea (windpipe) over the base of the heart
- Dilated caudal vena cava (returning oxygen poor blood to the heart)
- Enlarged liver (hepatomegaly)
- Enlarged left ventricle and atria chambers
- Leaking A-V heart valve disease
- Thin poorly contracting ventricle walls
- Abnormal heart beats (arrhythmias)
The "Rolls Royce" of therapy involves:
- ACE inhibitors
- Pimobendan (Vetmedin)
- Anti-arrhythmic drugs if life threatening
The use of diuretics and ACE inhibitors is discussed in A-V heart valve disease.
Pimobendan is a great drug but can be expensive for large breeds. It makes the heart contract in a stronger manner without increasing the heart's demand for oxygen. It also acts as an ACE inhibitor complementing other ACE inhibitors. It has replaced the use of Digoxin (Lanoxin).
Using all three products gives the best results.
Pimobendan was first released for human trials approx 20 years ago. Excellent results were obtained for people with dilated cardiomyopathy, however there were a number of sudden unexplained deaths at the time. It has since been discovered that in humans, Pimobendan cross reacts with Digoxin (Lanoxin) and that was the suspected cause of the deaths. Pimobendan is under trials again in Japan and may make its way back into human medicine.