heart failure Flashcards
what effects CO?
-stroke volumes-contractility, Preload, Afteroad
-heart rate
what is the most common decrease in contractility?
MI (EDV, SNS stimulation, myocardial o2 supply)
what most commonly effects preload?
increases directly with an increase in plasma volume
increases indirectly by a decrease in contractility
(ESV, Venus return)
what most commonly effects after load?
increased peripheral vascular resistance
(aortic pressure and aortic resistance)
what is the effect of increased preload have on ccontractility?
it increases contractility
how does increased preload increase contractility?
increased LVEDV increases the size of the lumen, leading to myocardial ischemia
increased LVEDV causes stretching of the myocardium
what changes in contractility are independent of preload?
-calcium channels in heart cells
what is heart failure?
the inability of the heart to supply the body and heart muscle with adequate circulatory pressure and volume
what is the acute type of heart failure?
MI
what are the chronic forms of heart failure?
hypertension,aortic stenosis, ventricular hypertrophy
what is CHF (left)?
the inability of the left ventricle to provide adequate blood flow to the heart and other vital organs throughout the systemic circulatory system
what is right side heart failure?
the inability of the right ventricle to provide adequate blood flow into the pulmonary circulation
what happens to the EF in systolic heart failure.
ejection fraction is reduced
what happens to the EF in diastolic heart failure?
EF is preserved
what happens when the heart is stretched too far?
contractility is decreased
what is EF?
a measurement of the percentage of blood leaving the heart each time it squeezes
what is preload?
the force that stretches the cardiac muscle prior to contraction. This force is composed of the volume that fills the heart from venous return
what is after load?
the amount of pressure that the heart needs to exert to eject the blood during ventricular contraction. This is recorded as the systolic pressure of the heart
how does hypoxia and acidosis effect contractility?
the shape of proteins get denatured, and loose function
what increases after load?
when there is an impediment to blood flow out of a chamber
Which chamber has increased afterload due to hypertension?
left ventricle
In response to increased afterload, how do cardiac cells adapt?
hypertrophy
-larger muscle cells decree the workload (require more o2)
-without increased supply the muscles tissue becomes hypoxic which decreases contractility
if _____ is decreased, the heart chambers don’t empty well
contractility
what is the effect on contractility on during an MI?
decreased in contractility
what does the effect on renal failure have on preload and contractility?
it increases preload
and decreases contractility
what effect does HTN have on after load?
it is increased
what does reduced EF and increased LVEDV have?
it increases preload
what effect does decreased renal perfusion and increased renin-angiotensin have?
it increases afterload
An impediment to outflow of blood initially increases the ____
afterload
hypertrophy results in an increased demand for?
oxygen
what is systole?
contraction
what is systolic heart failure?
Inability to pump blood properly due to poor contractility
the inability to pump blood properly due to poor contractility increases and decreases what?
increases preload
decreases stroke volume
and reduces stroke volume
what is the most common cause of systolic heart failure?
CAD
what drugs decreases workload on the heart?
morphine, nitrates, B-blockers
what medications increase contractility?
calcium
what do the drugs that treat systolic heart failure aim to do?
aim to decrease workload on the heart or to increase contractility
what is diastole?
relaxation
what is diastolic heart failure?
Chamber fails to fill properly (with enough blood)
decreases blood volume
how does the chamber fail to fill properly in diastolic heart failure?
heart is not pumping out enough blood
what is the response when the heart is not pumping out enough blood?
hypertrophy-to decrease volume
the walls then become stiff and non-compliant (harder to stretch)
-the chamber can’t accommodate a normal amount of blood
what is a common cause of diastolic heart failure?
chronic HTN- induced hypertrophy
what’s the treatment for diastolic heart failure?
reduce the HR to create more time between contractions and more time to fill
what are the causes of right heart failure?
pulmonary disease and L heart failure
in many pulmonary diseases, the vessels constrict. What effect does this have?
increases after load
causes peripheral edema
increases BHP
what are the common causes of left heart failure?
HTN, valvular disorders
-caues pulmonary edema and increased BHP
what are the common causes of left heart failure?
HTN, valvular disorders
-causes pulmonary edema and increased BHP
Pulmonary edema interferes with normal gas exchange in the lungs leading to?
decreased oxygenation in the blood
decreased contraction
blood backs up in the right side leading to R side heart failure
what are the symptoms of impaired CO in decompensated heart failure?
-rapid wt gain
-increases urine output
is there a cure to heart failure?
no
what do treatments of heart failure aim to do?
maximize CO and tissue perfusion and/or reduce the workload of the heart
what is most commonly prescribed for heart failure and what do they do?
diuretics decrease preload
what are all of the heart failure treatments?
-diretics
-digoxin
-low-sodium diet
-HTN,ATH,CAD treatments:
ACE inhibitors
Angiotensin II receptor blockers(ARBs)
Beta-blockers
Blood vessel dilators (nitrates)
Aldosterone antagonists
Calcium channel blockers
what does digoxin effect?
strengthens contractions
what does a low-sodium diet effect?
less preload which then effects bp lowering afterload
what do ARB’s do?
Angiotensin 2 causes constriction-inhibits that
what do B-blockers cause?
vasodilation
what do nitrates do?
vasodilator-decrease workload on the heart
what do Ca-channel blockers do?
decrease HR-reduce workload
