MATTERS OF THE HEART
“The heart has reasons that
reason does not understand.”
-Jacques Benigne Bossuel
DISEASES OF THE
CARDIOVASCULAR SYSTEM
CARIOMYOPATHIES
CANINE DILATED
CARDIOMYOPATHY
90% of cases occur in Doberman Pinschers and Boxers
OTHER BREEDS INCLUDE WOLFHOUNDS, GREAT DANES, AND COCKER
SPANIELS
CANINE DILATED CARDIOMYOPATHY:
PATHOPHYSIOLOGY
• DECREASED CONTRACTILITY FROM
AN UNKNOWN CAUSE (viral?, carnitine
deficiency?)
– Decreased contractility = decreased cardiac
output
CO (CARDIAC OUTPUT) = SV (STROKE VOLUME) X HR (HEART RATE)
The amt. of blood that leaves
The heart
Amt. of blood ejected with
Each cardiac contraction
(affected by afterload, preload,
and inherent contractility)
How often the heart
contracts
CANINE DILATED CARDIOMYOPATHY:
PATHOPHYSIOLOGY
• THE BODY COMPENSATES BY:
1. INCREASING THE HEART RATE
*this is done by sympathetic nervous
system stimulation
2. TRYING TO INCREASE STROKE VOLUME
BY INCREASING PRELOAD (this means that
the body increases filling of the heart)
*This is done by activation of the Reninangiotensin-aldosterone system which leads
to sodium and water retention
THE WALLS OF THE HEART ARE WEAK, FLABBY, AND DILATED – THIS
DILATION MAY CAUSE SEPARATION OF THE MITRAL VALVE LEAFLETS
LEADING TO MITRAL REGURGITATION
CANINE DILATED CARDIOMYOPATHY:
CLINICAL SIGNS
LETHARGY, EXERCISE INTOLERANCE, COUGHING, WEIGHT LOSS, TACHYPNEA,
SYNCOPE, SOFT MURMUR (WHERE?)
CANINE DILATED
CARDIOMYOPATHY:DIAGNOSIS
Enlarged, round heart
DOBERMANS ARE DEEP CHESTED AND MAY NOT APPEAR TO HAVE SUCH AN
ENLARGED HEART ON RADIOGRAPHS
CANINE DILATED CARDIOMYOPATHY:
DIAGNOSIS
PULMONARY EDEMA
PLEURAL EFFUSION
PATIENT MAY SHOW SIGNS OF LEFT-SIDED, RIGHT-SIDED, OR HEART
FAILURE FROM BOTH SIDES
CANINE DILATED CARDIOMYOPATHY:
PATHOPHYSIOLOGY, DIAGNOSIS
• Constant stimulation of the heart by the
sympathetic nervous system causes ventricular
arrhythmias and myocyte death
– Most common arrhythmias: VPC’s and ventricular
tachycardia, esp. in boxers & Dobies; other dogs
may have APC’s and atrial fibrillation
ONE VPC
MULTIPLE VPCs
CAUSING TACHY-CARDIA
CANINE DILATED CARDIOMYOPATHY:
DIAGNOSIS: ECHOCARDIOGRAM
http://www.youtube.com/watch?v=7TWu0_Gklzo&feature=related
http://www.youtube.com/watch?v=NSnh3qN2kR4&NR=1
PERFORMING AN ECHOCARDIOGRAM IS THE DEFINITIVE WAY TO DIAGNOSE
DILATED CARDIOMYOPATHY
CANINE DILATED CARDIOMYOPATHY:
TREATMENT
INCREASES CONTRACTILITY
REDUCES FLUID
RETENTION
DIURETIC-ELIMINATES EXCESS
FLUID
CANINE DILATED CARDIOMYOPATHY:
TREATMENT
COENZYME Q10
TAURINE – USED IN COCKER
SPANIELS AND CATS, MAINLY
L-CARNITINE
DIETARY SUPPLEMENTS THAT MAY HELP IMPROVE HEART FUNCTION, ESP
IF THERE IS A DEFICIENCY
FELINE DILATED CARDIOMYOPATHY
A globular-shaped heart with
severe dilation of all four
chambers. Depressed
ventricular contractile
performance occurs.
Ventricular dilation distorts the
atrioventricular valves leading to
mitral regurgitation and atrial
enlargement
ABNORMALLY THIN VENTRICULAR WALLS
ATROPHIED PAPILLARY MUSCLES
FELINE DILATED CARDIOMYOPATHY
• In the 1980’s DCM in cats was one of the
most commonly diagnosed heart diseases.
It was discovered that this was caused by
a deficiency of TAURINE, an amino acid.
• Since that time commercial foods have
added taurine to feline diets, which has
significantly decreased the number of
cases of feline DCM
DISEASES OF THE
CARDIOVASCULAR
SYSTEM
CARDIOMYOPATHIES
PATIENT PRESENTATION
http://www.youtube.com/watch?
v=X-wLIoYTpOU
http://www.youtube.com/watch?v=Zp7
CiC7SXjk
FELINE HYPERTROPHIC
CARDIOMYOPATHY
NEUTERED MALE CATS BETWEEN 1-16 YRS. OF AGE
THE MOST COMMON CARDIOMYOPATHY IN CATS!
FELINE HYPERTROPHIC CARDIOMYOPATHY:
CLINICAL SIGNS and DIAGNOSIS
• Soft, sytolic murmur
• Gallop rhythms or other arrhythmias
– ECG: ↑ p wave duration, ↑ QRS width, sinus
tachycardia
• Echo: shows ↑ ventricular wall thickness, dilated
left atrium
• Acute onset of heart failure
• Acute onset of systemic thromboembolism
– Hindlimb paresis
– Cold rear legs
– Painful rear legs
FELINE HYPERTROPHIC
CARDIOMYOPATHY
• THE PREDOMINANT PATHOLOGY OF
THIS DISEASE IS LEFT VENTRICULAR
HYPERTROPHY
• CAUSE:
– Genetics
– Related to abnormal myocardial myosin or
calcium transport within the muscles of the
heart
FELINE HYPERTROPHIC
CARDIOMYOPATHY
FELINE HYPERTROPHIC
CARDIOMYOPATHY: DIAGNOSIS
http://www.youtube.com/watch?v=yNj-lQaUBao
http://www.youtube.com/watch?v=KvUFb4qZwmw&feature=related
http://www.youtube.com/watch?v=xlsq5tJpj04&feature=related
FELINE HYPERTROPHIC
CARDIOMYOPATHY: Pathophysiology
PROBLEM #1: The walls lose compliance and resist filling during
diastole! (diastolic failure)
FELINE HYPERTROPHIC
CARDIOMYOPATHY: Pathophysiology
• PROBLEM #2: If the left ventricle cannot fill
adequately with blood, the blood backs up into
the left atrium (enlargement) → pulmonary veins
→ pulmonary edema!
• PROBLEM #3: The left atrium becomes dilated
with blood → the blood becomes static → blood
stasis leads to clot formation → clot becomes
dislodged and trapped elsewhere in the arterial
system → thromboembolism!
***90% of thrombi become lodged in the aortic trifurcation
causing “saddle thrombus”***
FELINE HYPERTROPHIC CARDIOMYOPATHY:
SADDLE THROMBUS
ACUTE, PAINFUL CONDITION CAUSING
PARESIS, COLD REAR LEGS/FEET!
FELINE HYPERTROPHIC CARDIOMYOPATHY:
SADDLE THROMBUS
FELINE HYPERTROPHIC
CARDIOMYOPATHY: TREATMENT
FUROSEMIDE (DIURETIC)
ASPIRIN
ANTICOAGULANT
OR
PROPRANOLOL (B-BLOCKER)
DILTIAZEM (CALCIUM CHANNEL BLOCKER)
FELINE HYPERTROPHIC
CARDIOMYOPATHY: TREATEMENT
• LASIX (furosemide): a diuretic used to treat
pulmonary edema
• DILTIAZEM: a calcium channel blocker used to
inhibit cardiac and vascular smooth muscle
contractility; reduces blood pressure and cardiac
afterload; overall improvement in diastolic function
– Or Propranolol: a beta-blocker to decrease heart rate
and myocardial oxygen demand
• ASPIRIN: an anticoagulant used to thin blood and
help prevent clot formation in HCM
• TPA (Activase): serves as a fibrolysin resulting in
the breakdown of clots that have already formed
– Or Heparin, Warfarin: acts on the coagulation factors to
inhibit the formation of a stable clot
FELINE HYPERTROPHIC
CARDIOMYOPATHY: CLIENT INFO
• There is no cure!
– Cats with HCM may experience heart failure,
arterial embolism, or SUDDEN DEATH!
– Cats whose heart rates stay below 200
beats/min have a better prognosis than those
whose heart rate is >200 beats/min
CANINE HYPERTROPHIC
CARDIOMYOPATHY:
• An UNCOMMON canine disease, but the
cause appears to be heritable
• CLINICAL SIGNS:
– Fatigue
– Sudden death
– Tachypnea
– Syncope
– Cough
• BREEDS: German Shepherds, Rottweilers,
Cocker Spaniels, and others