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

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?)

CANINE DILATED CARDIOMYOPATHY:DIAGNOSIS

Enlarged, round heartDOBERMANS ARE DEEP CHESTED AND MAY NOT APPEAR TO HAVE SUCH ANENLARGED 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 VPCsCAUSING TACHY-CARDIA

CANINE DILATED CARDIOMYOPATHY: DIAGNOSIS: 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: TREATMENT

INCREASES CONTRACTILITY

DIURETIC-ELIMINATES EXCESS FLUID

REDUCES FLUIDRETENTION

CANINE DILATED CARDIOMYOPATHY: TREATMENT

DIETARY SUPPLEMENTS THAT MAY HELP IMPROVE HEART FUNCTION, ESPIF THERE IS A DEFICIENCY

COENZYME Q10TAURINE – USED IN COCKERSPANIELS AND CATS, MAINLY L-CARNITINE

FELINE DILATED CARDIOMYOPATHYA 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

DISEASES OF THE CARDIOVASCULAR

SYSTEM

CARDIOMYOPATHIES

PATIENT PRESENTATION

http://www.youtube.com/watch?v=X-wLIoYTpOU

http://www.youtube.com/watch?v=Zp7CiC7SXjk

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 CAUSINGPARESIS, COLD REAR LEGS/FEET!

FELINE HYPERTROPHIC CARDIOMYOPATHY: SADDLE THROMBUS

FELINE HYPERTROPHIC CARDIOMYOPATHY: TREATMENT

OR

PROPRANOLOL (B-BLOCKER) DILTIAZEM (CALCIUM CHANNEL BLOCKER)

FUROSEMIDE (DIURETIC)

ANTICOAGULANT

ASPIRIN

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