Page 2 - Small Talk - Autumn 2014

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A heart murmur is an abnormal
sound heard when listening to
the heart with a stethoscope. It
is usually heard as a ‘whooshing’
noise when listening to the
‘lub-dup’ of a normal heart beat.
The murmur is caused by vibrations within the heart
or associated blood vessels. These vibrations are
often caused by turbulent blood flow. A good
analogy of this is that of a river flowing being
relatively quiet until it hits rocks, when the flow
becomes more turbulent and noisy.
The turbulence can be caused by many things. This
can include problems that animals can be born with,
such as malformed heart valves, “hole in the heart”
type defects, and mis-connected blood vessels.
Some problems become more obvious as an animal
grows, such as narrowing of major blood vessels
leaving the heart. Cats also can develop murmurs
associated with thickening of the heart muscle that
can occur in quite a wide age-range. Older animals
can develop “leaky” valves within the heart, which
can develop and progress as time passes.
There are other causes of heart murmurs, which
occur secondary to another problem elsewhere
in the body. Anaemia and dehydration are two
examples of this, but it may not be possible to tell by
listening to the murmur that there is a cause which
is not heart based.
In some cases the murmur may even be part of
normal flow within the heart, but further investigation
may be required to confirm this.
The murmur will often be graded on a scale where
1 is a very quiet murmur and 6 is the loudest.
Although a quieter murmur is often less concerning,
the grade of murmur does not necessarily directly
relate to the severity of the heart condition underlying
it. In some cases, and especially in cats, there may be
progressing heart disease with a fairly quiet murmur,
and in both dogs and cats a heart condition may
be present with no audible murmur. Equally some
animals may have a comparatively loud murmur for
many years without progressing rapidly.
An ultrasound scan of the heart (similar to the type of
scanner used for a pregnancy scan in humans), will
often help in identifying the source of a murmur.
Depending on the cause of the murmur, and the
individual patient, further investigation may be
beneficial which should be discussed with
your vet. This could include X-ray, ECG, blood
samples or blood pressure measurement.
Diabetes is a problem that can affect both dogs and cats and can be
more common in overweight pets. In this issue there is some great
advice on managing and preventing this problem.
Lindsay Grant from Northvet has a fascinating case study on
Ruby the 8 year old dog with a puzzling skin condition. Also
Tim Shearman from Minster explains heart murmurs,
what to look out for and how they are diagnosed.
In this
edition
of Small Talk...
Tim Shearman
BSc BVMS CertVC MRCVS
Minster Veterinary
Practice