DISEASES OF THE CARDIOVASCULAR SYSTEM

CANINE DILATED CARDIOMYOPATHY 90% of cases occur in Doberman Pinschers and Boxers OTHER BREEDS INCLUDE WOLFHOUNDS, GREAT DANES, AND COCKER SPANIELS

THE WALLS OF THE HEART ARE WEAK, FLABBY, AND DILATED

CANINE DILATED CARDIOMYOPATHY: PATHOPHYSIOLOGY DECREASED CONTRACTILITY from an unknown cause (viral?, carnitine deficiency?) Decreased contractility = decreased overall cardiac output CO (CARDIAC OUTPUT) = SV (STROKE VOLUME) X HR (HEART RATE) Squeezing a water bottle analogy Amt. of blood ejected with Each cardiac contraction (affected by afterload, preload, and inherent contractility) How often the heart contracts The amt. of blood that leaves The heart in a given unit of time

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 retaining sodium and water

CANINE DILATED CARDIOMYOPATHY: CLINICAL SIGNS LETHARGY, EXERCISE INTOLERANCE, COUGHING, TACHYPNEA, SYNCOPE, SOFT MURMUR, PLEURAL EFFUSION, ASCITES, HEPATOMEGALY

Normal Echocardiogram

Canine Dilated Cardiomyopathy Echocardiogram

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

CANINE DILATED CARDIOMYOPATHY Enlarged, round heart

CANINE DILATED CARDIOMYOPATHY PLEURAL EFFUSION PULMONARY EDEMA PATIENT MAY SHOW SIGNS OF LEFT-SIDED, RIGHT-SIDED, OR HEART FAILURE FROM BOTH SIDES

PULMONARY EDEMA VS PLEURAL EFFUSION Pulmonary edema is the accumulation of fluid in the ALVEOLI of the lungs Causes dyspnea due to air being displaced by fluid Left sided heart failure Pleural effusion is the accumulation of fluid in the pleural space OUTSIDE of the lungs Causes dyspnea due to lungs not being able to expand fully Right-sided and congestive heart failure

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: 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 DIGOXIN FUROSEMIDE REDUCES FLUID RETENTION ENALAPRIL DIURETIC-ELIMINATES EXCESS FLUID

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

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

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