Download What is a heart murmur? What is Mitral Valve Disease?

What is a heart murmur?
This is a common finding in lots of dogs, particularly as they get older. The murmur is
the noise your vet can hear with a stethoscope caused by a leaky heart valve. In the
majority of dogs it isn't a major concern and requires no further action.
However, a heart murmur can be a symptom of heart disease. There are two main heart
diseases affecting dogs:
–
Mitral Valve Disease (MVD)
–
Dilated Cardiomyopathy (DCM)
What is Mitral Valve Disease?
The mitral valve separates the heart's two main chambers, it acts like a one way gate
preventing blood flowing the wrong way round the heart each time it beats. With mitral
valve disease the valve becomes misshapen and leaky. We do not know the cause of this
disease, it just happens in some dogs as they get older.
MVD is most common in older small
breed dogs, Cavaliers are particularly
prone to this disease. Many dogs will
live with it happily for their whole life
and it never becomes a problem.
However in some dogs it will progress and eventually the heart will start to fail, at which
point we say they are in “congestive heart failure”. There is medication available to
improve these dogs' quality of life, but sadly there is no cure for this condition. We only
need to start treating dogs if or when their MVD starts affecting them, ie when you
notice symptoms of the disease, there is no proven benefit to early treatment.
What is Dilated Cardiomyopathy?
This is less common than MVD. It tends to affect giant breed dogs like great danes, wolf
hounds and deer hounds. Dobermen are particularly prone to this disease, but it can
affect any breed of dog. DCM is a disease of the heart muscle. Over time the muscle
gradually weakens and becomes floppy. The heart can no longer contract and pump
effectively. The chambers of the heart become enlarged and dilated. DCM is generally a
more serious disease than MVD, dogs with DCM nearly always progress to heart failure
and the progression tends to be much quicker than with MVD. Dogs with DCM can
sometimes develop an arrhythmia (irregular heartbeat). As for MVD there is medication
available to improve quality of life, but again sadly there is no cure. There is some
evidence to suggest that treating dogs with DCM in the early stages of the disease (ie
before you see any symptoms) dogs have a longer life expectancy. A heart scan is used
to diagnose this condition. For “at risk” breads, particularly dobermen, we recommend
screening heart scans to diagnose the disease as early as possible.
Heart Scans
If we find a murmur, we normally recommend having your dog's heart scanned. We use
an ultrasound scanner to look at the structure of the heart and take various
measurements of the heart. This will help us diagnose your dog’s condition and give us
an idea of how advanced any heart disease is. We also often recommend taking chest
xrays to check for any other causes of your dog's symptoms, eg a lung problem causing
coughing.
What to Expect When Your Dog is in for a Scan
A heart scan is a non-invasive procedure. We normally perform the heart scan without
any sedation or anaesthetic. We will normally keep your dog in for the morning for the
scan and they can go home the same afternoon or evening. We normally ask that dogs
are dropped off between 8.30 and 9am. However if you think your dog will be stressed
here, we sometimes arrange for you to come later in the day when it’s a bit quieter. Our
receptionists can arrange a suitable time for you. To perform the scan we need to clip an
area of fur on the right side of your dog’s chest, just behind their elbow. Sometimes we
will clip the left side as well. It’s not normally possible for you to be present during the
scan.
When should I worry?
Most dogs can have a heart murmur for many years before it (if ever) causes a problem.
Some dogs, the disease does progress and can cause congestive heart failure. This is
the term we use when your dog's heart and body can no longer cope with its level of
heart disease and it starts to show obvious symptoms.
The common symptoms of both MVD and DCM can often be quite mild and hard to
notice in the early stages of the disease. Watch out for:

Out of breath or refusing to exercise

Lethargy

Coughing, particularly at night time

Change in breathing

Decreased appetite

Fainting/weakness/collapsing
When the heart starts to fail, the knock on effect is a build-up of fluid on the lungs. This
will obviously affect your dog’s breathing. If you notice a change in your dog's resting
respiratory rate (how many breaths they take in one minute) this is a really useful early
warning sign, and it’s something only you can check at home. When your dog visits the
vets they are understandably nervous or excited and as a result their breathing will be
more rapid than at home. If you were to record how many breaths your dog takes in a
minute on a regular basis, this is really useful information for us. If you notice this
number start to increase, it’s an early warning sign there may be a problem, so get your
dog checked.
If your dog was to start showing symptoms of heart disease, we will fully discuss the
treatment options available and the best course of action for your dog. If you have any
questions please just contact us
01527 831 616