small animal cardio Flashcards
what is endocardiosis?
explain the pathophys
screwed up mitral valve
- with a bad mitral valve, extra fluid flows backward into the LA, increasing your pre-load.
- this decreases your CO and decreases the amount of blood going to the rest of the body.
- body interprets this as hypovolemia and turns on RAAS
- RAAS increases water retention an increases the flow to lungs and heart
- this overloads the LA
which valves are pre-disposed to endocarditis?
the L-heart: aortic and mitral valves
volume overload leads to what kind of hypertrophy
what kind of issues do you see this with?
VOLUME = ECCentric hypertrophy
seen with VALVULAR issues like mitral regurge
walls get stretched
pressure overload leads to what kind of hypertrophy?
what kind of issues do you see this with?
PRESSURE = CONcentric hypertrophy
seen with aortic and pulmonic STENOSIS
walls get thick
what medications treat mitral valve disease?
furosemide (lasix) - diuretic
- decreases preload, decreases work on the heart
enalapril (ace inhibitor)
- decreases aferload by decreasing blood pressure
difference between dogs and cats when it comes to showing signs of congestive heart failure?
dogs get pulmonary edema - fluid actually in lung tissue - in alveolar beds
cats get pleural effusion (fluid in between the lung itself and the pleura - the membrane covering the lungs)
clinical signs of congestive heart failure
- pulmonary edema (dog) or pleural effusion (cat)
- tachypnea or hypernea
- syncope
- coughing
- rads: mainstem bronchi compression (large pulmonary vessels); alveolar pattern (air bronchograms)
- bounding pulse
what are two diseases with bounding pulses?
- PDA
2. bacterial endocarditis
what causes increased venous pressure (which leads to jugular pulses)?
R-sided heart failure caused by tricuspid valve disease
emergency therapy for congestive heart failure
- furosemide (diuretic to decrease preload)
- anxyiolytics (opioids, diazepam, ace)
- arteriodilators (decrease afterload): enalapril (ace inhibitor); amlodipine (Ca channel blocker acts on vasculature)
- pimobendan (increases contractility)
chronic therapy for congestive heart failure
- diuretics = furosemide (for pulmonary edema)
- Ace-inhibiotr = enalapril (decrease afterload)
- vasodilator & Ca channel blocker = amlodipine (decrease BP)
- positive iontrope = pimobendan (increases contractility and dilates vessels)
- beta blockers = for arrhythmias
- Ca-channel blockers = diltiazem (slows HR)
bacterial endocarditis
usually mitral or aortic valves
- often staph/strep/E.coli or bartonella
- signalment: young, often large breed dog with sudden murmur after being sick
- CS: fever, polyarthritis, hyperkinetic or bounding pulses
- tx: abx IV for at least a week: ampicillin, baytril, azitrhomycin if its bartonella
what large breed dog is susceptible to DCM?
dobies! and danes
when cocker spaniels get DCM, it is often caused by a deficiency in what?
L-cartinine
explain the pathophys of DCM
- heart muscle isn’t working right (poor/loss of contractility)
- decreased CO
- causes sympathetic activation (RAAS, hormonal, etc)
- atrial fibrillation and VPCs are common sequelae bc conduction fibers are being pulled apart
- end up with both forward and backward failure
CS of DCM
- first sign can be sudden death
- TALL “R” WAVES!!
- ventricular arrhythmias
- weakness, tachypnea, exercise intolerance, ascites, syncope
how do you treat DCM?
- positive iontrope = pimobendan (increase contractility) AND digoxin (increases contractility and slows AV node conduction)
- Ace-inhibitor = Enalapril (decrease afterload to increase circulation)
+/- - Ca channel blocker = diltiazem (slow HR; centrally acting)
- beta blocker = sotalol (good for arrhythmias)
heartworm disease complications (other stuff it causes)
- leads to R-sided CHF
- cor pulmonale (heart disease caused by primary lung disease. pulmonary hypertension increases cardiac afterload and leads to R-sided hypertrophy)
- chronic inflammatory disease –> glomerulonephritis
what is the infective stage of heartworm?
L3
heartworm tests for dogs vs cats
the test looks for FEMALE antigen
cats can have single sex infections; so cats should have ANTIGEN tests
dogs should have Ab tests
cats = antigen dogs = antibody
treatment for HWD
doxycycline for wolbachia
melarsomine/immiticide
2 month protocol: doxy for 1 month, injection of adulticide; wait one month; then have the 2nd injection; repeat HW test 6 months post treatment
HW prevention
ivermectin
what diseases can cause systemic arterial hypertension? (8)
- CKD
- cushings
- hyperthyroidism
- pheochromocytoma
- diabetes
- liver dz
- hyperaldosteronism
- intracranial lesions
what are some clinical signs or evidence of systemic hypertension (4 main things)
- progression of chronic kidney disease
- eyes: retinopathy, acute blindness
- brain: encephalopathy or stroke
- heart and vessels: left ventricular hypertrophy
how do you treat systemic hypertension
- Ca channel blockers: amlodipine and diltiazem
- Ace inhibitors - enalapril
- beta blockers - atenolol, propranolol
what are some things that cause pulmonary hypertension (4 things)
- increased pulmonary blood flow
- increased blood viscosity (polycythemia)
- increased pulmonary vascular resistance
- luminal narrowing
how do you treat pulmonary hypertension?
sildenafil (viagra!)
tadalifil (cialis)
what breed of dog is susceptible to mitral valve dysplasia?
bull terriers
what breed is susceptible to sub-aortic stenosis?
newfoundlands and goldens
what does the murmur of a sub-aortic stenosis sound like?
systolic crescendo/decresendo murmur that is loudest over left heartbase
explain the pathophys of sub-aortic stenosis
- there is an outflow tract obstruction
- causes a pressure overload in the Left ventricle
- leads to a CONcentric hypertrophy
- poor ventricular filling and coronary perfusion leads to a lack of oxygen for the heart
- mycardiocytes die
- leading to arrhythmias
- causes a secondary mitral regurgitation
- eventually leads to low output failure which can result in death
clinical signs & diagnosis of sub-aortic stenosis
- rads show big LV
2. echo shoes CONcentric hypertrophy (from pressure overload)
treatment of sub-aortic stenosis
beta-blockers! causes relaxation and decreases afterload and arrhythmias
prognosis for sub-aortic stenosis
hint: what does this disease predispose dogs to?
px not good; 50% die suddenly
predisposes to infective endocarditis!!
what breed is predisposed to pulmonic stenosis?
bulldogs! and boxers
what is the pathophys of pulmonic stenosis?
it’s basically the same as sub-aortic stenosis but on the right side of the heart.
there is some obstruction that causes a pressure overload (CONCENTRIC hypertrophy) which leads to a Right ventricular hypertrophy with secondary dilation and right atrial enlargement.
given the pathophys of pulmonic stenosis, what is an unusual clinical sign of this disease?
the murmur is best heard over the LEFT heartbase (systolic crescendo/decresendo) despite the disease being a R-sided heart disease
(sounds very similar to sub-aortic stenosis)
how do you treat pulmonic stenosis?
balloon vulvuoplasty most common!
- causes pulmonic insufficiency, but that is better to have than stenosis
explain the pathophys of a PDA (patent ductus arteriosus)?
it is a shunt connecting the aorta (L-side) and pulmonary artery (R-side).
- blood is continuously pumped thru this patency in the aorta (L-side) to the pulmonary artery (R-side)
- this leads to overload of L atria, increases pressure on the right
- this will eventually reverse the shunt