Test 1: lecture 18: canine Flashcards
primary myocardial disease
Idiopathic or heritable disorders resulting in structural or functional abnormalities of the heart muscle
* Cardiomyopathies
secondary myocardial disease
inflammatory, metabolic, toxic or infiltrative disease of the myocardium with a known etiology or causative agent
* May or may not be reversible
two primary myocardial diseases
dilated cardiomyopathy (DCM)
Arrhythmogenic right ventricular cardiomyopathy (ARVC)
two secondary myocardial diseases
nutritional cardiomyopathy (taurine)
myocarditis
secondary dilated cardiomyopathy can be caused by
Nutritional factors – taurine, carnitine, other
* Toxins – chemotherapy
* Infection/inflammation – myocarditis
* Arrhythmias – chronic tachycardia
* Endocrine disease – hypothyroidism
— is Myocardial disease characterized by systolic dysfunction and secondary cardiac chamber dilation
dilated cardiomyopathy
what does heart with primary DCM look like
eccentric hypertrophy (thin walls- stretched out)
all four chambers but left>right
papillary muscles can be atrophies
heavy heart
histopath of DCM
- Attenuated wavy fibers
- Fibrofatty infiltration
- Myocyte atrophy/necrosis
- Minimal inflammation
DCM will lead to — stroke volume and — chambers
reduced
dilated
(impaired systolic function- reduced contractility)
what kind of failure will DCM cause
foward (poor ejection)
reduced cardiac output, hypotension → weakness and exercise intolerance
backward failure (congestion)
elevated ventricular end-diastolic pressure, high atrial pressures, high pulmonary venous pressure →CHF
what kind of dogs get DCM
large and giant male breeds
- Doberman Pinscher
- Boxer (ARVC)
- Giant breeds (GD, Newfie, Irish Wolfhound)
Exceptions: PWD, Manchester Terrier, Cocker Spaniel
Adults except PWD, Manchester Terrier (juvenile DCM)
clinical signs of DCM
from low output: weakness, lethargy, exercise intolerance, syncope, death
from congestion: cough, dyspnea, Orthopnea, insomnia, Abdominal distension, Anorexia, weight loss, Cardiac cachexia
why can you hear S3 with dog with DCM
ventricles do not fully empty (low output)
therefore when blood from atria pushed into ventricle will make a murmur
PE of dog with DCM
- Arrhythmia
- Pulse deficits
- Gallop heart sound (S3)
- Soft murmur (AV valves)
- Weak pulses
- Cold extremities
- Tachypnea, dyspnea
- Jugular distension, ascites
EKG of DCM
LV enlargement pattern
* Tall R wave
* Prolonged QRS duration (mild)
LBBB
* Prolonged QRS duration
Atrial enlargement pattern
* Increased P wave duration (P-mitrale)
* Increased P wave amplitude (P-pulmonale)
75% will get Afib
VPC
with ventricular tachycardia
Afib
75% of dogs with DCM will also have Afib
Xray of DCM
cardimegaly: left sided or generalized
left sided CHF
* distended pulmonary veins
* pulmonary edema : perihilar to caudodorsal, intersitial to alveolar
right sided CHF
* distended caudal vena vava
* pleural effusion
* ascites
DCM
large left atrium and ventricle (double opasity on VD)
diffuse perihilar and caudodorsal pulmonary edema
how to measure systolic function on echo
fractional shortening
ejection fraction
stages of DCM
stage 1: normal Heart, no signs
stage 2 occult: abnormal heart, no signs
stage 3 overt: abnormal heart with clinical signs/CHF
—% of dobermans have DCM
50-60
occurs in males 4-10 years old
sudden onset with syncope and CHF
DCM in dobermans
50-60% of all males 4-10 years old
sudden onset of symptoms: syncope and CHF
ventricular arrythmia more common then Afib
sudden death (VT→VF) 30-50%
CHF made worse by AFib
what genetic mutation in dobermans with DCM
autosomal dominant
incomplete, age related penetrance
PDK4 (DCM1)
DCM2
both mutations = 30% increased risk
