Treatment of Heart Failure

Question 1

6 categories of drugs that can treat heart failure

Answer 1

diuretics
ACE inhibitors
AT receptor blockers
Vasodilators
Beta-blockers
Cardiac glycosides

Question 2

what are possible causes of heart failure

Answer 2

myocardial damage
hypertension
genetic/congenital
chemical toxicity
infection

Question 3

difference between systolic and diastolic heart failure

Answer 3

systolic = reduced contractility
diastolic = reduced filling of the heart

Question 4

how does the CV system compensate for decreased cardiac output

Answer 4

• increased SNS activity
• increased renin-angiotensin system
• increased force of heart contraction
• ventrivular hypertrophy

Question 5

how does the SNS play a role in compensating for decreased cardiac output

Answer 5

• baroreceptors dewtect this change and cause reflex machanism
• increased SNS and decreased PSNS
• increases heart rate (force of contraction and PVR)

Question 6

symptoms of heart failure due to the SNS compensation response

Answer 6

tachycardia
sweating
fluid retention

Question 7

how does the renin-angiotensin system compensate for decreased cardiac output

Answer 7

• decreased CO means leass bloodflow to the kidneys
• get SNS activation of B1 receptors in kidneys
• Na+ and H2O retention by kidneys heads in increased blood volume and cardiac output
• increased renin released by kidneys leads to Angiotensin II being formed - binds AT1 receptors and nerve terminals to increase NE leading to increased PVR

Question 8

how does fluid retention and vasoconstriction help compensate for decreased cardiac output

Answer 8

increased BV in veins - increased pressure in blood returning to the heart - stretching of cardiac muscles - increased strength of contraction

Question 9

structural changes in the heart when we have decreased cardiac output

Answer 9

• have enlarged atria and ventricles
• more blood but not able to efficiently pump it out

Question 10

ventricular enlargement vs hypertrophy

Answer 10

enlargement: cavities dilate when cardiac muscle is weakened - volume good, strength bad
hypertrophy: cardiac muscle cells increase in size to componsate for stress - strength good, volume bad

Question 11

what is a compensated heart

Answer 11

heart functions normally at rest but may fail due to exercise or stress - due to compensatory mechanisms

Question 12

what is a decompensated heart

Answer 12

• severely damaged heart cannot be compensated by the SNS, renin-angiotensin system or ventricular hypertrophy
• excessive stretching of heart muscle weakens the heart further
• edema - excessive fluid in venous system can leak into tissues

Question 13

a combination of which conditions is termed congestive heart failure

Answer 13

decompensated heart + edema - need intervention!

Question 14

characteristics of conjestive heart failure

Answer 14

• insufficient CO to supply organs with nutrients and O2
• fluid accumulation in lower limbs or lungs
• reflex mechanisms worsen effects since normal CO cant be reached
• body cannot respond, must regulate heart yo pump blood more efficently

Question 15

symptoms of conjestive heart failure

Answer 15

tachycardia
shortness of breath
sweating
peripheral/pulmonary edema
decreased exercise tolerance
enlargement of heart
hypertension/hypotension
urine retention

Question 16

theraputic strategies for conjestive heart failure are aimed at…

Answer 16

reducing workload of the heart

Question 17

treatment strategies for conjestive heart failure - lifestyle changes

Answer 17

heathy diet
limit salt
limit alcohol and caffiene
decrease stress
exercise (cautious)
quit smoking

Question 18

treatment strategies for conjestive heart failure - surgical procedures

Answer 18

angioplasty
bypass treatment
transplant
ventricular pacemakers
left ventricular assist device

Question 19

what drugs are used to treat mild heart failure or patients with left ventricular dysfunction

Answer 19

ACE inhibitors (enalapril)
ARB (losartan)

Question 20

how do enalapril and losartan work on blood vessels to treat heart failure

Answer 20

• cause vasodilation
• devreased SVR and afterload
• reduce stress on the heart

Question 21

how do enalapril and losartan work on the heart to treat heart failure

Answer 21

• decrease afterload, preload and edema
• increases ejection fraction
• results on decreased oxygen demand for the heart

Question 22

how do enalapril and losartan work on the kidney to treat heart failure

Answer 22

• decreases Na/H2O reabsorption
• decreases BV and CO
• decreases preload
• decrease overall stress on the heart (benefit on the heart > difr rffrct of decreased CO)

Question 23

what drugs are used to treat heart failire in patients with edema

Answer 23

diuretics (furosemide) - first-line treatment for patients woth pulmonary edema
vasodilators (long-acting nitrates)

Question 24

what drugs are used to treat patients with excessive tachycardia

Answer 24

low dose B-blockets (metoprolol)
- must be cautious becasue we have decreased CO

Question 25

cardiac glycosides in treating heart failure

Answer 25

- effective but can be toxic so don't use as first-line treatment - use in patients who remain symptomatic after treatment - use in patients who have CHF and atrial fibrilation or enlarged dysfunctional left ventricle

Question 26

characteristics of Digoxin (cardiac glycoside)

Answer 26

- absorbed and distribited well - direct effect (heart) - indirect effect (baroreceptors)

Question 27

mechanism of cardiac glycosides (e.g. digoxin)

Answer 27

- inhibits Na+/K+ ATPase - leads to increased force and decrease rate of contraction (heart fills more efficiently and doesnt have to work as hard to pump blood out)

Question 28

direct effect of digoxin (cardiac muscle cells)

Answer 28

increases Na+ inside cell - decreases Ca2+ efflux out of cell - increases intracellular Ca2+ - increases interaction between actin and myosin - INCREASED CARDIAC CONTRACTILITY

Question 29

indirect effect of digoxin (baroreceptors)

Answer 29

improved circulation - baroreceptors respond - increased PSNS activity and decreased SNS activity

Question 30

administration of digoxin

Answer 30

- long half life (40 hours) - to achieve theraputic doses quickly, patients given large initial dose followed by daily maintenence dose - maintenence adjusted based on body weight, kidney function and plasma digoxin levels

Question 31

cardiac toxicities of digoxin

Answer 31

arrhythmias in patients with low K+ levels (from diuretics or diarrhea) which can lead to tachycardia and fibrillation

Question 32

toxicities of digoxin from drug interactions

Answer 32

interaction with quinidine (anti-arrythmic drug) reduces digoxin clearance - inclreases plasma levels and can lead to toxicity

Question 33

GI/CNS toxicity of digoxin

Answer 33

anorexia nausea vomitting and diarrhea dizziness headaches vision disturbances

Question 34

what happens when Na+/K+ ATPase enzyme is inhibited in cardiac cells

Answer 34

- reduces the exchange of K+ for Na+ which reduces Na+ and Ca2+ - more Na+ and Ca2+ remains in the cell - more Ca2+ = increased rate and force of contraction