cardiovascular: the cardiac cycle Flashcards
whats isovolumic contraction and relaxation
isovolumic contraction: LV contracts-> AV valve and aortic valve is shut; volume is the same, LV pressure increases
isovolumic relaxation: LV relaxes-> AV valve and aortic valve is shut; volume is the same, LV pressure drops
whats a dicrotic notch
during LV relaxation, aortic valve shuts-> U shape in aortic pressure graph
explain PV loop: axis/corners/boundaries
x-axis: LV volume; y-axis: LV pressure
(REFER TO SLIDES)
LHS vertical line: isovolumic relaxation
RHS vertical line: isovolumic contraction
bottom horizontal line: ventricular filling
top horizontal line: ventricular ejection
top left corner: aortic valve closes
bottom left corner: mitral valve opens; end-systolic volume
bottom right corner: mv closes; end-diastolic volume
top right corner: aortic valve opens
how to find stroke volume + stroke work from PV loop
stroke work: area contained in loop
stroke vol: end diastolic vol- end systolic vol
jugular venous pulse location; monophasic/biphasic and parts
located next to carotid artery
biphasic curve
a-wave: atrial contraction; PEAK
c-wave: carotid pulse (from carotid artery, which runs next to jugular vein)
x-wave: atrial relaXation (minimum point)
v-wave: atrial filling during Ventricular systole-> tricuspid valve bulges-> RA pressure +
y-wave: passive atrial emptYing
arterial pulse monophasic/biphasic; peaks present
monophasic
high peak (120) due to high pressure from heart
subsequent peak due to reflective wave (when aorta and arteries recoil), affected by
reflected waves/compliance/resonance/interference/damping
where does jugular vein collapse and why does it collapse
about 5cm above RA; pressure increases closer to the heart.
due to hydrostatic influences and low venous pressure
how to measure jugular venous pressure
what’s pathological
why does the pt have to be in this position
make pt lie at 45 deg angle-> JVP is vertical height of jugular vein measured from manubriosternal angle
>3cm is pathological
if pt was upright, point of collapse would be lower and cant be seen. If pt was lying down, there would be no point of collapse
how does tricuspid stenosis affect shape of JVP
tricuspid stenosis is the narrowing of valve
a-wave is larger: atrial pressure increases more than it should as valve is narrower
v-wave is diminished: tricuspid valve does not bulge back very much
how does tricuspid regurgitation affect shape of JVP
a-wave is diminished
v-wave is enhanced (ventricular contraction sends blood through regurgitative valve into atrium-> + RA pressure)
primary heart sounds
LUB: AV valve closes
DUB: semilunar valves close
extra, pathological heart sounds
AV valves open and rapid refilling occurs
atrial systole
causes of heart murmurs
turbulence of blood flow due to valve stenosis or valve regurgitation
types of heart murmurs and their causes
systolic: mitral regurgitation/aortic stenosis
diastolic: mitral stenosis/aortic regurgitation
