Heart failure (exam 2) Flashcards
(104 cards)
heart failure is a
cardiomyopathy
heart failure
inadequate ability of the heart to pump enough blood to meet the metabolic demands of the body
HF results from a _________________ due to a _______________
reduction in cardiac output
reduction in stroke volume
common symptoms of HF
fatigue
tachycardia
edema
dyspnea
exercise intolerance
Ejection fraction =
stroke volume/end diastolic volume
heart failure with reduced ejection fraction (HFrEF)
systolic HF
dilation of ventricles (dec SV, inc EDV)
EF under 40%
heart failure with preserved ejection fraction (HFpEF)
diastolic HF
stiffening of myocardium (dec SV, dec EDV)
EF over 50%
cardiac output =
stoke volume x HR
stroke volume is affected by
preload
afterload
contractility
preload is dependent on
venous return
venous return is dependent on
fluid volume and venous tone
preload
the pressure within the ventricle
stretching of the myocytes at the end of diastole
increase in fluid volume or venous vasoconstriction leads to
increase in venous return leads to
increase in preload
increase in preload and SV
afterload
resistance to ejection of blood from the ventricle
after load is dependent on
arterial tone
arterial vasoconstriction leads to
increase in after load and decrease in SV
contractility is dependent on
ANS and Calcium
activation of beta1 receptors and intracellular Ca leads to
activation of M2 receptors leads to
increase contractility and SV
dec contractility and SV
Frank starling law
volume of ejected blood by the ventricle depends on volume/pressure present in the ventricle at the end of diastole
when the myocardial fibers are stretched more, the blood ejected from the heart
increases due to greater force of contraction
is increase in preload sufficient for patients with HF to maintain SV?
no
compensatory mechanisms in HF
increased preload
vasoconstriction
tachycardia and increased contractility
ventricular hypertrophy and remodeling
cardiac remodeling
changes in size, shape and function of the heart following injury
cardiac remodeling is associated with the development and progression of
ventricular dysfunction and arrhythmias