Test 1: lecture 5 +6: CHF treatment

Question 1

what are some goals of CHF treatment

Answer 1

improve systolic and diastolic function

get rid of aggravating conditions: arrhythmia, HTN

control edema

avoid drug adverse effects

Question 2

cat with HCM will have — hypertrophy with impaired —

Answer 2

concentric ventricular

Impaired diastolic relaxation
Increased myocardial stiffness (decreased compliance)
Normal systolic function

Question 3

why does HCM cause congestion

Answer 3

big stiff LV requires more pressure to push blood out of heart

increased preload causes increased diastolic pressure → congestion

increased pressure leads to back up to the venous/capillaries causing edema

Question 4

what drug to increase fluid excretion in cat

Answer 4

loop diuretics: lasix (furosemide)
1-2 mg/kg IV cat
0.5-1.0 mg/kg/day oral cat

natriuresis (increased sodium excretion)

Question 5

two ways to decrease preload and congestion

Answer 5

increased fluid excretion → diuretics (Lasix)

increase venous capacitance→ venous vasodilators (Nitrates)

Question 6

Nitrates will cause — and does what to preload

Answer 6

venous vasodilation

will decrease preload and congestion

nitroglycerine pasts: 1/8-1/4 inch cutaneoudly q6-8 hrs

Question 7

what are some ACE inhibitors

Answer 7

—april

enalapril, benazepril, lisinopril ect

blocks angiotensin 1 from changing into angiotensin 2, prevents RAAS pathway

Question 8

how does ACE inhibitor work

Answer 8

blocks angiotensin 1 from changing into angiotensin 2, prevents RAAS pathway

arterial vasodilation: will reduce afterload

decrease Na/H2O resorption: reduce preload

reduce angiotensin 2/ aldosterone myocardial hypertrophy

Question 9

how will ACE inhibitor effect the preload/CO graph

Answer 9

will reduce preload ( decrease Na/H20 resorption) and reduce afterload (arterial vasodilation)

Question 10

how to reduce myocardial work

Answer 10

myocardial oxygen demand (MVO2)= systolic BP x HR

can either decrease BP or decrease HR

can’t go to low on either but some wiggle room

Question 11

what drugs are used to slow HR and increase diastolic filling time in cat

Answer 11

beta adrenergic receptor blockers (Atenolol)

Calcium channel blockers (Dilacor)

Question 12

how do beta-adrenergic receptor blockers work

Answer 12

decrease sympathetic tone
decrease impulse to sinus node

will cause slow HR and increased diastolic filling time

Atenolol 6.25-12.5 mg/cat/day

Question 13

how does caclium channel blockers work

Answer 13

decreased calcium dependent depolarization

slows impulse of SA node

slows HR and allows for increased diastolic filling time

Dilacor 30-60 mg/day cat

Question 14

— olol drugs are for

Answer 14

beta blockers

slow HR

atenolol

Question 15

side effects of diurectics

Answer 15

Hypovolemia
electrolyte abnormalities
pre-renal azotemia
acute kidney injury (increased BUN, Creat)

Question 16

side effects of afterload reducers

Answer 16

hypotention

kidney injury

arterial vasodilators (ACE inhibitors) (enalapril)

Question 17

side effect of beta blockers and Calcium blockers

Answer 17

bradycardia

beta blocker: atenolol
Ca blocker: dilacor

Question 18

how to treat acute life threatening CHF in dogs

Answer 18

FOND

furosemide
oxygen
nitro
dobutamine, dopamine, digoxin

Question 19

dose of Lasix in cat and dog

Answer 19

Lasix
Dog
2-4 mg/kg IV/IM q 2-3 hrs (has shorter 1/2 life in a dog)
2-3 mg/kg/day PO

Cat
1-2 mg/kg IV/IM (cat) q 2-3 hrs
0.5-1.0 mg/kg/day PO

Question 20

how to monitor furosemide

Answer 20

short 1/2 life in dogs

monitor urine output, hydration status and renal function

could use constant rate infusion in dogs- reevaluate frequently

Question 21

how does furosemide work

Answer 21

needs to be activly transported across PCT in the kidney from the blood into the tubule lumen

kidney needs to work for furosemide to work

receptor needs to be avilable - NSAIDs can block this transport

Question 22

what happens to the dose of lasix needed over time

Answer 22

need more for same result
diminished response
Braking effect

kidney tries to go around lasix

Question 23

what is Braking effect

Answer 23

kidneys response to diuretic

decrease in plasma volume will cause increase in RAAS

kidney gets angry and goes into over drive

Question 24

if low O2 what to do?

Answer 24

oxygen cage give 40% O2
intranasal give 100% O2
positive pressure ventilation: expensive

normal air O2=21%

Question 25

how to give nitroprusside

Answer 25

IV only very short half life CRI: 2-10 microgram/kg/minute for dog protect from light, dilute with 5% detrose, degrades in plastic will cause venous and arterial vasodilation: monitor for hypotension

Question 26

nitroprusside in a dog will cause

Answer 26

**Venous vasodilation**: reduce preload **Arterial vasodilation**: reduce afterload ## Footnote very short half life, IV only, CRI

Question 27

dobutamine effects ---

Answer 27

sympathetic tone will bind to B1 receptors on SA node and heart muscle to cause increased contractility side effect: tachycardia

Question 28

name an inotrope used to treat CHF in a dog

Answer 28

dobutamine will increase sympathetic tone synthetic B1-agonist- increase calcium into the cell increase contractility of the heart ## Footnote digoxin, dobutamine, dopamine: increase Calcium in the cell pimobendan- inodilator

Question 29

side effects of dobutamine

Answer 29

tachycardia increase sympathetic function by increasing amount of Ca in the cell which increases contractility of the heart very short half life: CRI: 5-15 microg/kg/min

Question 30

how does dopamine work

Answer 30

**B-agonist**: increase amount of calcium in the cell which increases HR and contractility also binds to **⍺ receptors**: cause vasoconstriction **side effects:** tachycardia and vasoconstriction monitor rate and rhythm

Question 31

what are some drugs to slow Afib in a dog

Answer 31

**Ca channel blocker**- decease Ca in SA node= decrease HR- **dilacor** **B-blocker**- **atenolol**- decrease HR by decrease sympathetic impulse to SA node **Digoxin** binds to and inhibits the sodium/potassium-ATPase (sodium pump) within the plasma membrane of cardiac myocytes- leads to more sodium= **more calcium**= increase contractality

Question 32

how to treat dog with low cardiac output, low contractility and hypotension

Answer 32

give fluids inotropes- dobutamine to increase contractability of heart by increasing Ca in the cell by acting as B-agonist

Question 33

at home treatment for CHF in dog

Answer 33

**Furosemide** **Oxygen** **Ace inhibitor**-**enalapril** prevent RAAS pathway: arterial vasodilation(decrease afterload), decrease Na resporption (decrease preload), decrease angiotensin II mediated myocardial hypertrophy **Pimobendan**- inodilator- increase contractlility(by increasing calcium sensitivity of actin and myosin), arterial vasodilator (phosphodiesterase inhibitor)

Question 34

how does pimobendan work

Answer 34

**inodilator** increase contractlility(by increasing calcium sensitivity of actin and myosin) arterial vasodilator (phosphodiesterase inhibitor) | better contractility without increasing workload of the heart

Question 35

compare energy requirment for Dobutamine vs Pimobendan

Answer 35

both act as positive inotropes: increase contractility inside the cell **Dobutamine** works by increasing the amount of Calcium inside the cell (acts as B1-agonist, increases sympathetic impulse) = **high energy expenditure** **Pimobenden**: makes actin and myosin more sensitive to calcium as well as acts as arterial vasodilator: **low energy**

Question 36

typically starting dose of lasix for dog and cat

Answer 36

Dog: 2mg/kg/day Cat: 1-1.5mg/kg/day can increase to Dog: 1-3mg/kg q8-24hrs as needed Cat: 1-2mg/kg q12-24hrs as needed

Question 37

what is an uncommon effect of ACE inhibitors

Answer 37

renal dysfunction ace inhibitor can cause **vasodilation** of cells inside efferent blood vessels of glomerulus. This causes **hypotension** inside the kidney and decrease in function leading to **hyperkalemia**

Question 38

what is aldosterone escape

Answer 38

when you give ACE inhibitor body finds a different way to make aldosterone

Question 39

how does spironolactone work?

Answer 39

aldosterone receptor antagonist use in addition to ACE inhibtor to prevent aldosterone escape prevents aldosterone from retaining sodium, causing myocardial damage

Question 40

aldosterone antagnosits are --- sparing diuretics

Answer 40

potassium ## Footnote spironolactone: work in DCT and collecting duct

Question 41

spironolactone is a ---

Answer 41

aldosterone antagnoist acts as a potassium sparing diuretic anti-remodeling/hypertrophy effect rather than diuretic action

Question 42

side effects of spironolactone

Answer 42

dehydration, renal injury, hyperkalemia aldosterone antagnoist: acts as potassium sparing diuretic

Question 43

chronic heart failure in dogs is treated with --- drugs

Answer 43

FAPS furosemide ACE inhibitor pimobendan spironolactone

Question 44

digoxin works as a --- inotrope

Answer 44

positive increases contractility

Question 45

--- has replaced digoxin in treatment of CHF

Answer 45

pimobendan digoxin still used to slow ventricular HR (Afib)

Question 46

what is diurectic resistance

Answer 46

over time may need to increase or add new drug to get same diuretic effect

Question 47

how to treat refractory and end stage HF

Answer 47

make sure pet actually getting meds increase meds: increase furosemide dose or increase dosing schedule for ACEI remove excess fluid manually (tap the chest or abdomen)

Question 48

what are other diuretics you can use for refractory CHF

Answer 48

thiazide: works in DCT Torsemide: works in loop ## Footnote cause **sequential nephron blockade**: stop Na in multible areas of nephron

Question 49

--- is a venous vasodilator, sorta like an oral nitro

Answer 49

isosorbide dinitrate rapid development of tolerance

Question 50

what are some atrial vasodilators other then ACEI

Answer 50

amlodipine hydralazine limited by hypotension

Question 51

cats with --- usually last 9-12 months ending with --- and ---

Answer 51

cardiomyopathy thromboembolism, bradycardia

Question 52

dogs with --- usually last 9 months with end signs of

Answer 52

mitral regurgitation atrial fibrillation, pulmonary hypertension, atrial tears

Question 53

dogs with --- last 6 months with end signs of

Answer 53

dilated cardiomyopathy atrial fibrillation, ventricular arrhythmias

Question 54

goals of chronic CHF therapy are

Answer 54

  Prevent congestion –  Interrupt maladaptive neurohormonal systems –  Maintain hemodynamics –  Avoid adverse side effects –  Maintain high quality of life

Question 55

goals of acute CHF therapy are ---

Answer 55

Alleviate congestion Improve hemodynamics