MATTERS OF THE HEART
“The heart has reasons that reason does not understand.”
-Jacques Benigne Bossuel
DISEASES OF THE CARDIOVASCULAR SYSTEM
CANINE DILATED CARDIOMYOPATHY
OTHER BREEDS INCLUDE WOLFHOUNDS, GREAT DANES, AND COCKER SPANIELS
90% of cases occur in Doberman Pinschers and Boxers
CANINE DILATED CARDIOMYOPATHY: PATHOPHYSIOLOGY
DECREASED CONTRACTILITY FROM AN UNKNOWN CAUSE (viral?, carnitine deficiency?)Decreased contractility = decreased cardiac
outputCO (CARDIAC OUTPUT) = SV (STROKE VOLUME) X HR (HEART RATE)
The amt. of blood that leavesThe heart
Amt. of blood ejected withEach cardiac contraction(affected by afterload, preload,and inherent contractility)
How often the heartcontracts
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 Renin-angiotensin-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 LEAFLETSLEADING TO MITRAL REGURGITATION
CANINE DILATED CARDIOMYOPATHY: CLINICAL SIGNS
LETHARGY, EXERCISE INTOLERANCE, COUGHING, WEIGHT LOSS, TACHYPNEA,SYNCOPE, SOFT MURMUR (WHERE?)
PLEURAL EFFUSION, ASCITES, HEPATOMEGALY, WT. LOSS
CANINE DILATED CARDIOMYOPATHY
Enlarged, round heartDOBERMANS ARE DEEP CHESTED AND MAY NOT APPEAR TO HAVE SUCH ANENLARGED HEART ON RADIOGRAPHS
CANINE DILATED CARDIOMYOPATHY
PULMONARY EDEMA PLEURAL EFFUSION
PATIENT MAY SHOW SIGNS OF LEFT-SIDED, RIGHT-SIDED, OR HEART FAILURE FROM BOTH SIDES
CANINE DILATED CARDIOMYOPATHY: PATHOPHYSIOLOGY
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 VPCsCAUSING TACHY-CARDIA
CANINE DILATED CARDIOMYOPATHY: ECHOCARDIOGRAM
http://www.youtube.com/watch?v=NSnh3qN2kR4&NR=1
PERFORMING AN ECHOCARDIOGRAM IS THE DEFINITIVE WAY TO DIAGNOSEDILATED CARDIOMYOPATHY
http://www.youtube.com/watch?v=7TWu0_Gklzo&feature=related
CANINE DILATED CARDIOMYOPATHY: DIAGNOSTICS
Laboratory testsAtrial Natriuretic peptide increase
Released from atria in response to excess stretchBrain natriuretic peptide increase
released from ventricles in response to excess stretch
Pro-BNP releaseTroponin 1 (cTn1) increased
Released when heart muscle is damaged
CANINE DILATED CARDIOMYOPATHY: TREATMENT
INCREASES CONTRACTILITY
DIURETIC-ELIMINATES EXCESS FLUID
REDUCES FLUIDRETENTION
DIGOXIN
FUROSEMIDE
ENALAPRIL
CANINE DILATED CARDIOMYOPATHY: TREATMENT
DIETARY SUPPLEMENTS THAT MAY HELP IMPROVE HEART FUNCTION, ESPIF THERE IS A DEFICIENCY
COENZYME Q10 TAURINE – USED IN COCKERSPANIELS AND CATS, MAINLY
L-CARNITINE
CANINE DILATED CARDIOMYOPATHY: CLIENT INFO
DCM is a progressive diseases that is almost always fatalMost dogs die within 6 months -2 yearsDeath may occur suddenly due to arrhythmias
FELINE DILATED CARDIOMYOPATHY
A globular-shaped heart withsevere dilation of all fourchambers. Depressedventricular contractileperformance occurs.Ventricular dilation distorts theatrioventricular valves leading tomitral regurgitation and atrialenlargement
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
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