Name
Cardiomyopathy
(Dilated)
Canine
Short
Description
Dilated
cardiomyopathy
The
dogs
most
frequently
diagnosed
with
DCM
are
large
and
giant
purebred
dogs,
including
Scottish
deerhounds,
Doberman
pinschers,
boxers,
Saint
Bernards,
Afghan
hounds,
Newfoundlands,
and
old
English
sheepdogs.
Recently,
both
English
and
American
cocker
spaniels
have
been
diagnosed
more
frequently
with
DCM
than
other
small
breed
dogs.
Most
dogs
with
DCM
are
older,
as the
prevalence
of DCM
increases
with
age.
Male
dogs
are
affected
more
commonly
than
female
dogs
for
most
breeds.
The
term
cardiomyopathy
literally
means
"sick
heart
muscle."
Dilated
cardiomyopathy,
or DCM,
occurs
when
the
heart
muscle
is
thin,
weak,
and
does
not
contract
properly.
DCM
most
commonly
affects
large
or
giant
purebred
dogs,
but it
also
can be
seen
in
smaller
breeds
such
as
cocker
spaniels,
and in
mixed
breed
dogs.
The
condition
can
lead
to
congestive
heart
failure,
in
which
fluid
accumulates
in the
lungs,
the
chest
or
abdominal
cavities,
or
under
the
skin.
Because
of
reduced
blood
flow
to the
rest
of the
body,
DCM
also
can
result
in
weakness,
fainting,
and
exercise
intolerance.
Abnormal
heart
rhythms,
or
arrhythmias,
frequently
accompany
DCM,
and
can
complicate
the
treatment
of
dogs
with
this
disease.
In
rare
cases,
supplementation
with
substances
such
as l-carnitine
or
taurine
may
dramatically
reduce
signs
in
individual
patients,
but
for
most
dogs,
the
main
goals
of
treatment
are to
lessen
signs
due to
congestive
heart
failure
and to
attempt
to
improve
the
heart's
ability
to
pump
blood.
The
long-term
outlook
for
dogs
with
DCM is
usually
quite
poor,
and
most
dogs
with
DCM
eventually
die
from
the
disease.
Despite
the
poor
long-term
outlook,
however,
many
dogs
with
DCM
can
benefit
from
medical
treatment
that
helps
control
symptoms.
Signs
may be
consistent
with
right
heart
failure,
left
heart
failure,
or
both.
Right
heart
failure
signs
can
include
abdominal
distention
due to
ascites,
jugular
venous
engorgement
or
pulsation,
hepatomegaly,
pleural
effusion,
edema,
pericardial
effusion,
and
weight
gain
due to
fluid
retention.
Left
heart
failure
signs
can
include
cough
due to
pulmonary
edema,
shortness
of
breath,
tachypnea,
and
dyspnea.
Some
signs
can be
seen
with
right
or
left
sided
heart
failure,
including
fatigue
and
weakness,
exertional
dyspnea,
gallop
rhythm,
pallor,
increased
capillary
refill
time,
cyanosis,
cool
extremities,
and
weight
loss.
Dogs
with
dilated
cardiomyopathy
can
show
symptoms
due to
right-sided
congestive
heart
failure
including
abdominal
enlargement;
distention
of the
veins
in the
neck
or
other
parts
of the
body;
and
fluid
accumulation
in the
abdomen
or
chest,
in the
sac
around
the
heart
or
underneath
the
skin,
especially
in the
legs
and on
the
underside
of the
body.
This
fluid
retention
can
lead
to
weight
gain.
Other
dogs
will
show
evidence
of
lung
problems
due to
left-sided
congestive
heart
failure,
including
shortness
of
breath,
rapid,
shallow
breathing,
difficulty
resting
comfortably
at
night,
and
coughing.
It is
also
common
for
dogs
with
DCM to
show
signs
of
both
right
and
left
heart
failure.
These
signs
can
include
weakness
and
exercise
intolerance,
and
difficulty
breathing
with
increased
activity.
Weight
loss
is
common
in
dogs
with
DCM
that
do not
retain
fluid.
Some
animals
exhibit
signs
due to
reduced
blood
flow
to
tissues,
including
pale
mucous
membranes,
bluish
color
to the
mucous
membranes,
and
cold
feet
and
legs.
Fainting
may
occur
if
abnormal
heart
rhythms
are
present,
or if
the
heart's
output
is
severely
reduced.
Heart
failure
occurs
when
the
blood
returning
to the
heart
from
the
rest
of the
body
cannot
be
pumped
out
fast
enough
to
meet
the
demands
of
body
tissues.
Heart
muscle
disease
is one
of the
potential
causes
of
heart
failure.
Dilated
cardiomyopathy
is a
condition
characterized
by a
variety
of
changes
in the
heart
muscle
that
result
in
pump
failure.
As the
name
implies,
the
heart
chambers
are
usually
dilated
or
enlarged,
and
the
heart
muscle
itself
is
usually
thin
and
weak,
contracting
with
much
less
vigor
than
normal.
The
term
cardiomyopathy
literally
means
"sick
heart
muscle."
The
primary
abnormality
occurring
with
DCM is
impaired
function
of the
ventricles
due to
decreased
strength
of the
heart
muscle.
The
left
ventricle
pumps
blood
from
the
lungs
to the
rest
of the
body,
and
the
right
ventricle
pumps
blood
from
the
rest
of the
body
to the
lungs.
When
the
heart
muscle
fails,
pressures
can
increase
and
ultimately
lead
to
left-
or
right-sided
heart
congestive
heart
failure.
Reduced
output
from
the
heart
may
result
in
signs
such
as
weakness,
exercise
intolerance,
fainting,
and
shock.
Heart
valve
insufficiencies,
abnormal
heart
rhythms
or
arrhythmias,
and
the
results
of the
body's
compensatory
responses
to
reduced
heart
muscle
performance
can
compound
the
problems
seen
with
DCM.
Ventricular
arrhythmias
can
often
lead
to
sudden
death,
especially
in
boxers
and
Doberman
pinschers.
The
development
of an
atrial
arrhythmia
called
atrial
fibrillation
can
have
important
short-term
and
long-term
consequences
for
dogs
with
DCM.
This
arrhythmia
can be
seen
in all
breeds
of
dogs.
Medications
are
used
to
treat
the
consequences
of
heart
muscle
failure,
to
attempt
to
improve
the
heart
muscle's
ability
to
contract,
and to
normalize
or
improve
rhythm
disturbances.
Drugs
used
to
accomplish
these
goals
include
diuretics,
digoxin,
and
angiotensin
converting
enzyme
inhibitors.
Supplementation
with
substances
such
as
taurine
or l-carnitine
may be
helpful
for
some
dogs
with
DCM.
The
diagnosis
often
is
first
suspected
when
symptoms
compatible
with
DCM
are
present
in a
large
or
giant
purebred
dog or
cocker
spaniel.
Physical
examination
abnormalities
frequently
include
the
presence
of an
extra
heart
sound
called
a
gallop
rhythm,
or a
soft
heart
murmur.
Arrhythmias
can be
detected
while
listening
to the
heart
with a
stethoscope
and
while
feeling
for
the
pulse
or
heartbeat.
Abnormal
lung
sounds
are
heard
in
dogs
with
left-sided
heart
failure,
while
distention
or
pulsation
in the
jugular
veins,
liver
enlargement,
or
abdominal
fluid
accumulation
may be
present
in
dogs
with
right-sided
heart
failure.
In
addition,
laboratory
results
may
indicate
mild
changes
in
serum
protein
concentrations,
sodium
and
potassium
levels,
liver
enzymes,
and
mild
increases
in
serum
urea
nitrogen
and
creatinine
levels,
or
kidney
values.
Although
they
will
not
always
reveal
major
changes,
chest
x-rays
should
always
be
evaluated
in
patients
suspected
of
having
heart
disease.
Heart
enlargement
and
blood
vessel
changes
consistent
with
heart
failure
may be
seen,
and
fluid
accumulation
in or
around
the
lungs
can be
identified
if
heart
failure
has
developed.
The
most
definitive
diagnostic
test
for
DCM is
the
echocardiogram,
an
ultrasound
evaluation
of the
heart.
Heart
chamber
dilation
and
enlargement,
reduced
heart
muscle
wall
thickness,
and
decreased
heart
muscle
wall
movement
are
the
hallmarks
of DCM.
In
addition,
mild
heart
valve
abnormalities
may be
seen.
Doppler
echocardiography
may be
used
to
assess
the
severity
of
valvular
abnormalities
based
on
changes
in
blood
flow
through
the
heart.
The
electrocardiogram
may
identify
abnormal
rhythms
or
changes
in the
normal
tracings.
The
most
common
rhythm
disturbance
occurring
with
DCM is
atrial
fibrillation,
a
condition
characterized
by a
tremendous
increase
in the
rate
of
contraction
of the
atria,
the
uppermost
chambers
of the
heart,
coinciding
with
an
increased
rate
of
contraction
of the
ventricles,
the
lower
and
larger
chambers
of the
heart.
Other
rhythm
disturbances,
including
premature
ventricular
beats,
may be
detected.
Currently,
DCM is
almost
always
fatal.
Most
dogs
die
within
six to
24
months
after
being
diagnosed.
Severely
ill
dogs
often
do not
survive
the
first
two
days
in the
hospital.
Doberman
pinschers
may
have a
worse
prognosis
compared
to
other
breeds.
However,
the
response
to
treatment
will
vary
for
any
individual
dog.
Treatment
should
always
be
attempted
before
rendering
a
prognosis.
As
with
almost
any
disease,
dogs
diagnosed
with
DCM
before
serious
complications
have
developed
may be
able
to
live
longer
with
treatment.
There
appears
to be
a
strong
association
between
breed
and
DCM.
Infectious
diseases,
including
Lyme
disease,
bartonellosis,
and
trypanosomiasis,
have
been
reported
in
association
with
DCM
and
are
usually
accompanied
by
other
symptoms.
DCM
generally
is not
curable,
and
spontaneous
recovery
is
unlikely.
The
primary
goals
of
treatment
are to
lessen
clinical
signs
of
heart
failure
and to
prolong
survival.
Treatment
of an
individual
dog is
dictated
by the
severity
of its
signs
at the
time
of
diagnosis,
and
the
presence
or
absence
of
changes
such
as
congestive
heart
failure
and
arrhythmias.
The
primary
drug
to
reduce
fluid
accumulation
secondary
to
congestive
heart
failure
is
furosemide,
marketed
as
Lasix.
It can
be
used
to
treat
acute,
life-threatening
fluid
accumulation
or to
control
and
prevent
congestive
abnormalities
in
chronic
settings.
Digoxin
is
used
for
several
reasons
in the
treatment
of DCM.
It may
help
increase
the
heart's
ability
to
contract
and
slow
down
the
ventricular
response
rate
in
dogs
with
atrial
fibrillation.
Digoxin
also
blunts
some
of the
neurological
and
hormonal
responses
to
heart
failure
that
lead
to
worsening
of the
condition.
Drugs
such
as
dobutamine,
amrinone,
and
milrinone
may be
used
to
increase
the
heart
muscle's
ability
to
contract,
but
they
are
indicated
primarily
for
short-term
emergency
situations.
Recently,
the
use of
drugs
called
angiotensin
converting
enzyme,
or
ACE,
inhibitors
has
been
shown
to
benefit
dogs
with
DCM by
reducing
the
signs
due to
heart
failure
and
improving
exercise
tolerance.
ACE-inhibitors
have
many
effects,
including
blood
vessel
dilation,
which
reduces
the
resistance
the
heart
has to
pump
against.
The
drug
also
remodels
the
diseased
heart
muscle.
Other
types
of
blood
vessel
dilators
can be
used
in the
short-term
or
long-term
treatment
of DCM
to
reduce
the
load
that
the
heart
has to
pump
against
to get
blood
to
flow.
Other
drugs
control
heart
rhythm
disturbances.
Digoxin
is
commonly
used
in
dogs
with
atrial
fibrillation.
Other
anti-arrhythmic
drugs,
including
procainamide,
marketed
as
Procan,
and
mexiletine,
marketed
as
Mexitil,
are
used
for
dogs
with
ventricular
arrhythmias
due to
DCM.
L-carnitine
is a
compound
that
plays
an
important
role
in
fatty
acid
metabolism
and in
neutralizing
potential
toxins
in
cells.
Carnitine
deficiency
in the
heart
muscle
has
been
shown
to be
potentially
reversible
in at
least
one
family
of
boxers
with
DCM.
Although
the
diagnosis
of
heart
muscle
carnitine
deficiency
is
difficult,
and
the
appropriateness
of
supplementation
with
l-carnitine
for
all
dogs
with
DCM is
unknown,
such
supplementation
is not
known
to be
harmful.
L-carnitine
supplementation
can be
considered
for
all
dogs
with
DCM.
Another
substance
that
may
play a
role
in the
treatment
of DCM,
particularly
in
cocker
spaniels,
is
taurine.
Taurine
deficiency
was
found
to be
the
most
important
factor
associated
with
DCM in
cats
in the
1980's,
and
correction
of cat
food
formulations
to
eliminate
taurine
deficiency
resulted
in the
almost
complete
elimination
of DCM
as a
major
heart
muscle
disease
in
cats.
However,
the
exact
role
of
taurine
in the
treatment
of DCM
in
dogs
remains
undetermined.
Other
substances,
such
as
coenzyme
Q-10,
may
also
play a
role
in the
treatment
of
this
disease.
Affected
dogs
should
not be
bred.
Early
screening
of
dogs
of
breeds
that
have a
high
incidence
of DCM
may
help
identify
important
changes
prior
to the
onset
of
signs.
This
can
help
prevent
the
breeding
of
dogs
that
could
pass
DCM on
to
their
offspring.
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