ARVC Flashcards
ARVC is the most common adult-onset heart dz in what breed?
boxers
what are the three forms of ARVC?
1) asymptomatic with VPCs
2) symptomatic with VPCs
3) ventricular dilation, systolic dysfunction, and ventricular and supraventricular tachyarrythmias
T/F: ARVC is primarily a dz of electrical dysfunction and most echos look normal
TRUE, grossly most hearts look normal
10% have ventricular and atrial dilation and CHF
ARVC is caused by a deletion mutation in what gene?
striatin
T/F: all dogs with the deletion mutation in striatin gene develop ARVC
FALSE, it’s an autosomal dominant trait with incomplete penetrance (can have the genotype but not the phenotype)
T/F: dogs homozygous for the deletion mutation in striatin gene usually develop a more severe form of ARVC
TRUE
what is the primary site for ARVC?
right ventricle
what does the histopath of ARVC look like?
fatty infiltration, myocyte vacuolization, myocyte loss
what are some major effects of ventricular tachycardia that can be seen in ARVC?
decreases CO (not enough time for ventricle to fill) > decreases SV
loss of atrioventricular synchrony > further reduction in CO and SV
what is the average age of boxers that are diagnosed with ARVC?
5-7
T/F: ARVC can be diagnosed in boxers as young as 3 or 4 and therefore dz frequency does not increase with age
FALSE, though boxers can be diagnosed younger than 5-7, dz frequency and severity INCREASE with age
what are the most common signs/presenting complaints of ARVC?
syncope and exercise intolerance
T/F: sudden death may be the first sign of ARVC in some boxers
TRUE! primarily electrical dysfunction, majority are asymptomatic
what might you hear when ausculting a boxer with ARVC?
premature beats, brief pauses, paroxysmal tachycardia
you hear a murmur at the left heart base on a boxer. why would you need to echo this dog?
some boxers have benign heart murmurs, use to differentiate
VPCs from the right ventricle are positive in what lead?
lead II
does a normal ECG in a boxer rule out ARVC?
NO, lots of day to day variability and compared to the large number of heart beats in a day you may miss VPCs. use a holter monitor!
you have a type III ARVC boxer. what could you see on echo?
dilation & systolic dysfunction (lack of robust contraction)
when would you consider treatment for ARVC?
> 1000 VPCs/24 hrs (normal 0-50), runs of ventricular tachycardia, or R-on-T phenomenon
what is the first choice in treatment for dogs with ARVC?
sotalol (class III anti-arrhythmic)
caution in patients w/ systolic dysfunction because can make worse in the short-term as it has some beta-blocking effects
what drugs would you consider in treatment of refractory ventricular tachycardia?
combination of anti-arrhythmics or amiodarone (mostly class III but broad spectrum of classes)
what supplements that can have anti-arrhythmic effects might you consider in adding to your treatment plan for a dog with ARVC (in addition to your anti-arrhythmic drugs)?
omega-3 fatty acids, DHA, EPA
if a boxer has ARVC with concurrent systolic dysfunction what drugs should you add to the regime (other than your anti-arrhythmics)?
ACE inhibitors and pimobendan (+furosemide & spironolactone if in CHF)
at what point should you recheck your patient with a holter monitor after starting drug therapy for ARVC?
2-3 weeks after starting a new drug or changing dose
what is considered a positive response in regards to a holter monitor for a patient you started drug therapy for ARVC?
> 80% reduction in VPCs
what symptoms are most common in a cat with ARVC (uncommon)?
R-CHF symptoms (tachypnea, dyspnea, jug v. distension, ascites)
T/F: like boxers with ARVC, arrhythmias are uncommon
FALSE, arrhythmias (tachycardia and bradycarida) are common in cats
what might you see in radiographs of a cat with ARVC?
RA and RV enlargement +/- pleural/peritoneal effusion (usually seen!)
are echos most helpful in diagnosing ARVC in dogs or cats?
cats!! RV and RA dilation, aneurysmal buldge or abnormal motion of ventricular wall, systolic dysfunction, tricuspid regurgitation
