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