Feline Cardiomyopathies: Part 2 Flashcards
pathogenesis of HCM, RCM
- primary diastolic dysfunction
- increased LV filling pressure, left atrial enlargement and dysfunction
- leads to increased pulmonary venous pressure
- leads to increased pulmonary capillary pressure as blood backs up into left atrum and then into capillaries
how can you diagnose HCM
- requires echo! end diastolic wall thickness measurements >6mm
- diastolic and systolic function assessment
- atrial size assessment: the bigger the atrium the bigger the problem
clinical staging of all feline CMs
- stage A: predisposed (ex maincoon kitten)
- stage B1: low risk for adverse outcomes of dz: subclinical/preclinical/occult
- stage B2: higher risk of adverse outcomes: subclinical/preclinical/occult
- stage C: current/previous CHF/ATE: clinical and symptomatic
- stage D: end stage: refractory CHF: bad and death
how do we treat cats in stage B of HCM?
- asymptomatic cat
- cannot really treat. drugs being studied, but no effective treatment
can’t use pimobendan in cats: it increases contraction: this is not the problem in cats; their problem is FILLING - treatment decisions based on risk assessment (echo findings) and “pillability”
3 adverse outcomes of cardiomyopathies in cats (and these might be why you treat subclinical HCM cats)
- sudden cardiac death: challenging to predict, systolic dysfunction, ventricular arrhythmias. pimobendan considered for systolic dysfx, antiarrhythmics
- heart failure: assess risk by ATRIAL ENLARGEMENT and decreased atrial pump function
- arterial thromboembolism: if atrial enlarged, at risk! spontaneous echogenic contrast “smoke” on echo
what is our big assessment for heart failure?
ATRIAL ENLARGEMENT
ACEi sometimes considered to delay CHF but lacks evidence
what finding on echo leads you to believe a cat has ATE?
spontaneous echogenic contrast “smoky death swirl” visualized on echo: these are platelets swirling around and starting to stick together: these embolize and then become ATE
what medications are used when you suspect the beginnings of an ATE?
- clopidogrel: makes platelets less sticky
can also do factor Xa inhibitor
when do you use beta blockers for HCM cases?
using beta blockers (atenolol) less common for subclinical HCM. good when they have OBSTRUCTIVE HCM: will decrease heart rate and contractility
if asymtomatic won’t really treat
- indirect evidence for using with stage B2
clinical recognition of stage C HCM (CHF, ATE)
- clinical signs: breathing difficulty, tachypnea, sick cat
- cardiogenic pleural effusion, pericardial effusion, thoracocentesis if effusion
- cardiogenic pulmonary edema
T/F: you should not tap pericardial effusion in cats
true
T/F: you should not tap pleural effusion in cats
false, you should do in pleural effusion. not in pericardial effusion!
what should you do before thoracic radiographs in a CV dz cat?
POCUS and tap if needed
in cats, cardiogenic pleural effusion might be ______
chylous: milky strawberry appearance in cats
how can you differentiate that pleural/pericardial effusion or edema is cardiogenic and not neoplastic/pyothorax, etc?
- ECHO
- look for unequivocal LA enlargement (or biatrial enlargement!)
- if you can fit more than 2 aortic diameters in the LA, that is big
- LA/Ao short axis >1.7, LA dimension long axis >18mm
- would start empirical furosemide when associated with breathign difficulty
point of care SNAP NT-proBNP in cats?
- helpful in dyspneic cats
- > 270 pmol/L is what suggests cardiogenic causes of dyspnea
- POC/SNAP cutoff = 100 (150) pmol/L
- ^ false positives possible
- confident in results if it is normal/negative
- should not replace thoracic radiographs, POCUS or both
how do you manage acute/in hospital CHF in cats?
- sedation + oxygen!
- empirical furosemide IM or IV (ideal) - cornerstone treatment
- thoracocentesis?
- minimize stress, step-wise diagnostics
what settings is furosemide/lasix good for?
- removing fluid from the LUNGS to get it out of interstitium and removed via urine
- does NOT work for removing fluid from body CAVITIES. think of it more as a prevention for that
how do you manage chronic/at home CHF in cats?
- stage C/D
- oral furosemide bid
- clopidogrel (plavix) - because atrium is enlarged and pt is thus at risk for ATE
(as soon as you see clinical improvement, back off the furosemide so you don’t induce kidney issues)
but once in CHF, will be in HF rest of life: either controlled or uncontrolled - need to maintain pt in maintained state - pimobendan? case by case decision
what are the 2 most important medications for at home management of CHF in cats?
- furosemide
- clopidogrel (plavix)- anti platelet stickiness
4 possible outcomes of HCM in cats
- nothing: live normal life
- death/euthanasia from CHF/refractory CHF/end organ failure
- death or euthanasia related to ATE
- sudden cardiac death
prognosis of HCM in cats
- variable
- might be reversible: can get transient myocardial thickening
- subclinical HCM: can live normal life to years if no atrial enlargement!!*
- CHF: months to 1.5 years, owner dependent
- ATE: bad prognosis
- bad px if: older, LA enlargement, LV systolic dysfx, ATE
what are the initial treatments of choice for a cat experiencing CHF with large volume pleural effusion and breathing difficulty?
thoracocentesis and furosemide
what drug can help prevent an arterial thromboembolism in a cat with hypertrophic cardiomyopathy?
clopidogrel
