Cardiovascular Flashcards
atrioventricular valves control blood flow from the _________ and they are the __________
atria to ventricle; mitral (left) (bicuspid) and tricuspid (right)
semilunar valves control flow from ________ and are the ________
ventricles to pulmonary artery or to the aorta; pulmonic semilunar valve and septic semilunar valve
blood flow through the heart/body
vena cava -> right atria -> tricuspid valve -> right ventricle -> pulmonary valve -> through pulmonary artery and to lungs -> returns from lungs as oxygenated blood and comes back into the left atria through the pulmonary veins -> mitral valve -> left ventricle -> out aorta and to the rest of the body
systole is the
ventricle contracting and sending blood out to the body
diastole is the
ventricles relaxing and filling up with blood from the atria
action potential is
the explosion of electrical activity created by depolarize event which is how the heart knows when to contract and relax. Depolarization = contraction (systole) Repolarization = relaxation (diastole)
order of electrical conduction system
SA node -> AV node -> bundle of His -> bundle branches R and L -> purkinje fibers
primary pacemaker of heart is the
SA node
secondary pacemaker of the heart
AV node
preload
amount of blood returning to R side of heart
after load
pressure against which the L ventricle must pump to eject blood
compliance
how easily the heart muscle expands when filled with blood
contractility
strength of contraction of heart muscle
stroke volume
volume of blood pumped out of the ventricles with each contraction
cardiac output
amount of blood heart pumps through circulatory system in a minute
autonomic nervous system control of the heart
sympathetic - increase electrical conductivity and myocardial contraction (epi and norepi)
parasympathetic - slow conduction of action potentials through the heart, reduce strength or contraction (acetylcholine)
Beta adrenergic receptors
B1 - in heart: increase HR and contractility (chronotropy and intropy)
B2 - in lungs: causes bronchodilation
ejection fraction
amount of blood ejected per heartbeat - should be 55% or higher; indicated ventricular function
stroke volume is determined by
preload, after load, contractility
cardiac output equation
CO = SV x HR
why is CO important?
tissue perfusion
end organ function
delivery of oxygen and nutrients
S&S or poor CO
decreased LOC
chest pain, weak peripheral pulses
SOB, crackles, rales
cool, clammy, mottled extremities
decreased urine output
causes of decreased CO
bradycardia, arrhythmias, hypotension, MI, cardiac muscle disease
causes of increase CO
sometimes increased blood volume and tachycardia, medications including ACE inhibitors, ARBS, nitrates, inotropes
normal CO
4-8 L/min
Central venous pressure
2-6 mmHg
MAP define
average arterial pressure throughout one cardiac cycle - systole and diastole
MAP normal
70-100 mmHg
MAP must be at least ____ for adequate perfusion of vital organs
60 mmHg
systemic vascular resistance define and normal
resistance exerted on circulating
blood by the vascular of the body
800-1200
antihypertensives
ACE inhibitors, ARBs, Calcium channel blockers, beta blockers, arterial and venous dilators
ACE inhibitors
reduce after load by acting on RAAS - blocks conversion of angiotensin (less volume = less pressure), increases renin levels, decreased aldosterone leading to vasodilation
Nursing considerations ACE inhibitors
dry cough (discontinue), monitor BP, angioedema, contraindicated during pregnancy
ACE inhibitors end in
-pril
ARBs end in
-sartan
ARBs
inhibits vasoconstrictive properties of angiotensin
ARBs nursing considerations
monitor BP, monitor fluid levels, monitor renal and liver status, contraindicated during pregnancy
Calcium channel blockers end in
-ipine or -pril
Calcium channel blockers
block transport of calcium into muscle cells inhibiting excitation and contraction (cause Ca acts as a sedative so by blocking it we are doing the opposite) inhibits excitation and contraction, causes peripheral vasodilation
nursing considerations for calcium channel blockers
avoid grapefruit, monitor bp (orthotic hypotension), can cause gingival hyperplasia
arterial dilators
cause decreased BP, arterial vasodilation, reduction in after load, increased CO
Hydralazine and minoxidil
venodilators
reduce preload, reduce venous returns to the heart, dilates arteries at higher doses
nitrates
betablockers end in
-lol
betablockers
antiarrhythmic; blocks beta 1 and 2 adrenergjc receptors which slow the heart rate
can also help with htn
beta blocker nursing considerations
do not discontinue abruptly, can mask signs of hypoglycemia, can potentially cause bronchospasm (caution with asthma and COPD)
by influencing the electrolytes going in and out of the heart we can control the __________________
electrical activity
amiodarone
potassium channel blocker, antiarrhythmic, stops potassium from leaving cells and prolongs rest period
amiodarone nursing considerations
dizziness, tremors, ataxia, pulmonary fibrosis, bradycardia, heart block, blue gray skin discolouration, has iodine and can disturb thyroid, not given in pregnancy
Adenosine is used for
SVT
adenosine is the medication version of _______________
cardioversion
Nursing considerations for adenosine
there will be a period of asystole
needs to be a rapid push or it will not work
client will feel “like they have been kicked in the chest”
adenosine needs to be used with caution in pts with _____________
asthma
Atropine is use for
excessive scretions (anticholinergic), sinus bradycardia, heart block