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 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 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 LEAFLETS LEADING 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 heart DOBERMANS ARE DEEP CHESTED AND MAY NOT APPEAR TO HAVE SUCH AN ENLARGED 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 VPCs CAUSING TACHY-CARDIA

CANINE DILATED CARDIOMYOPATHY: ECHOCARDIOGRAM PERFORMING AN ECHOCARDIOGRAM IS THE DEFINITIVE WAY TO DIAGNOSE DILATED CARDIOMYOPATHY

CANINE DILATED CARDIOMYOPATHY: DIAGNOSTICS Laboratory tests  Atrial Natriuretic peptide increase Released from atria in response to excess stretch  Brain natriuretic peptide increase released from ventricles in response to excess stretch Pro-BNP release  Troponin 1 (cTn1) increased Released when heart muscle is damaged

CANINE DILATED CARDIOMYOPATHY: TREATMENT INCREASES CONTRACTILITY DIURETIC-ELIMINATES EXCESS FLUID REDUCES FLUID RETENTION DIGOXIN FUROSEMIDE ENALAPRIL

CANINE DILATED CARDIOMYOPATHY: TREATMENT DIETARY SUPPLEMENTS THAT MAY HELP IMPROVE HEART FUNCTION, ESP IF THERE IS A DEFICIENCY COENZYME Q10 TAURINE – USED IN COCKER SPANIELS AND CATS, MAINLY L-CARNITINE

CANINE DILATED CARDIOMYOPATHY: CLIENT INFO DCM is a progressive diseases that is almost always fatal  Most dogs die within 6 months -2 years  Death may occur suddenly due to arrhythmias

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