CHF, Cardiac output

Question 1

What is CHF

Answer 1

It’s the hearts inability to efficiently pump/supply blood to the rest of the body.

Question 2

What is the main cause of left sided HF

Answer 2

MI that weakens the myocardium

Question 3

Describe the patho of Left sided HF

Answer 3

• The left ventricle is weak = can’t pump blood properly. Creates a back up of blood in the pulmonary circulation and lowers blood pressure.
• Increase pressure in pulmonary capillaries = pulmonary edema.
• Increases LV preload cuz blood isnt being ejected properly.
• Causes peripheral vasoconstriction, increased afterload, and increased heart workload.

Question 4

What’s the most common cause of Right sided HF

Answer 4

Left sided HF

Question 5

Describe the patho of right sided HF

Answer 5

• The increased BP in pulmonary circulation (caused by L sided HF) makes it harder for the R ventricle to pump blood.
• Blood backs up into the systemic circulation.

Question 6

What are S/S of CHF

Answer 6

• Fatigue
• Irregular HR
• Peripheral edema
• JVD (R)
• Pulmonary edema/Crackles
• SOB
• Orthopnea (diff. breathing lying down)
• Decreased urine output

Question 7

What are some causes of CHF

Answer 7

• MI
• A-fib
• HTN (it increases afterload)
• Renal failure
• Valvular disease
• COPD
• Congenital heart defect
• Endo/myocarditis
• Chronic anemia

Question 8

What kind of medication would a patient with CHF be taking

Answer 8

• ACE inhibitors
• ARBs
• Aldosterone receptor antagonist
• Beta blocker
• Digoxin
• Thiazide/Loop diuretic

Question 9

What are some compensation mechanism seen in CHF

Answer 9

• Sympathetic activation = Increased HR, contractility, and vasoconstriction
• Activation of RAAS (due to low BP) = increases Na+ and H2O reabsorption = increases preload.
• Heart may become hypertrophic = less ability to stretch and decreases contractility.
• Compensation mechanism are not a long term solution and will lead to decompensation

Question 10

What is the cardiac output formula

Answer 10

CO = HR x SV

Question 11

What is Stroke Volume

Answer 11

The amount of blood ejected by the heart during each heart beat (contraction)

Question 12

What factors influence SV

Answer 12

• Contractility
• Preload
• Afterload

Question 13

Describe preload and the factors that influences it

Answer 13

• Preload: amount of blood entering the ventricles during diastole
• Influcenced by: venous return, blood volume, and atrial contraction

Question 14

Describe afterload and the factors that influences it

Answer 14

• Afterload (resistance): The amount of resistance the ventricles must overcome to circulate the blood.
• Influenced by artherosclerosis and vasoconstriction
• Vasodilation = decreased resistance = increases blood ejected
• Vasocontriction = increased resistance = decreases blood ejected