canine myocardial disease

Question 1

Arrhythmogenic right ventricular cardiomyopathy (ARVC)

Answer 1

diseaes characterized by fatty or fibro-fatty replacement of the myocardium

predominately affects the right ventricle, +/- LV

results in myocardial dysfunction, ventricular arrhythmias, sudden death, CHF

Question 2

etiology of ARVC

Answer 2

familial disease: autosomal dominant trait with incomplete penetrance

mutation within desmosmal protein-striatin (key component of gap junction)

other causes?

Question 3

clinical presentation of ARVC

Answer 3

syncope

exercise intolerance

abdominal distension

respiratory distress

Question 4

PE findings of patients with ARVC

Answer 4

often normal

arrhythmia-extrasystoles, tachycardia

murmur

signs of CHF

Question 5

diagnosis of Arrhythmogenic right ventricular cardiomyopathy

Answer 5

histopathology

based on family hx of disease, evidence of cardiomyopathy, genotype, presence of ventricular arrhythmia (ventricular tachycardia, >1000 VPCs in 24 hours on holter), postmortem

Question 6

ECG of Arrhythmogenic right ventricular cardiomyopathy

Answer 6

ventricular tachycardia

positive VPCs

starting in RV going to LV

Question 7

treatment of Arrhythmogenic right ventricular cardiomyopathy

Answer 7

lidocaine-acute management

Sotalol-most commonly used, less side effects

amiodarone-hepatotoxic (patients usually on long term)

Question 8

px of Arrhythmogenic right ventricular cardiomyopathy

Answer 8

many dogs die of sudden death

some will die within short time period regardless of therapy

many affected dogs can live for years with or without therapy

Question 9

atrioventricular cardiomyopathy

Answer 9

progressive myocardial disease characterized by atrial fibrosis and enlargement, bradycardia, congestive heart failure, death

lose effects of SA node

Question 10

atrioventricular cardiomyopathy affected dogs

Answer 10

springer spanials, english sheep dogs, <3 yo

Question 11

atrioventricular cardiomyopathy presenting signs

Answer 11

weakness, synope, signs of heart failure

Question 12

atrioventricular cardiomyopathy PE findings

Answer 12

bradycardia, CHF signs-ascites

Question 13

atrioventricular cardiomyopathy ECG

Answer 13

atrial standstill

Question 14

what chemotherapeutic agent causes cardiotoxicity

Answer 14

doxorubicin

anthracycline

Question 15

myocarditis

Answer 15

focal or diffuse inflammatory process involving the myocardium

may result in arrhythmias, myocardial dysfunction, sudden death

Question 16

myocarditis etiology

Answer 16

viral-parvo

protozoal-Chagas’ toxoplasma, neospora

mycotic-blastomycosis

bacterial-borreliosis

Question 17

myocarditis pathophysiology

Answer 17

inflammation in myocardium disrupts normal electrical conduction-arrhythmias (VPC’s ventricular tachycardia)

myocardial dysfunction: inflammation induces myocardial necrosis, phenotypic change similar to DCM

Question 18

myocarditis dx

Answer 18

difficult

presumptive if: arrhythmias (absent of other diseases), ECHO, hx of systemic illness

ECG, ECHO, myocardial bx, elevated myocardial biomarkers (cardiac troponin I)

Question 19

troponin I

Answer 19

should be tightly bound to the thin filament

released with destruction of myocardial cell and thin filament-accumulate in plasma

following myocardial necrosis-detectable within 5-7 hours, peak: 12-48 hours, persist for 8 days, half life-2 hr

not specific for any one etiology

Question 20

myocarditis tx

Answer 20

treat underlying cause

anti-arrhythmics

pacemarker

corticosteroids