Cardiac cycle Flashcards
Draw and annotate the lines for aortic pressure, LA pressure, LV pressure, LV volume
ref. notes
Draw the pressure volume loop and annotate. Mark the SV
ref. notes
How to calculate stroke work from pressure-volume loop
Area within loop
Draw the wave for jugular venous pressure and annotate it
ref. notes
atrial contaction, carotid pulse (jugular vein next to carotid artery so when heart beats, contraction causes mini pulse), atrial relaxation, atrial filling during ventricular systole, passive atrial emptying (biphasic, lower pressure)
Draw the peripheral arterial pulse and describe
ref. notes
essentially monophasic, reflective wave caused by recoil when wall of vessel wall stretch during contraction. Shape of descending phase influenced by reflected waves, compliance, resonance, interference, damping.
How to check if JVP pathological
recline patient by 45 degree and see if the level of vein collapse is less than 3cm from manubriosternal angle. The more the vein is distented (the higher up towards the head it is), the higher the JVP
Why internal jugular vein used and not external for estimating CVP
Internal closer to RA while external doesn’t directly drain to SVC
internal is valveless and pulsations can be seen
vasoconstriction and secondary hypotention can make external barely visible
external more superficial and prone to kinking
how does tricuspid stenosis alter JVP
ref. notes
1st pulse enhanced as RA pressure rises higher during atrial contraction due to increased resistance of tricuspid valve.
v wave diminished as ventricular pressure wave tends not to be effectively transmitted back through stenotic inflexible tricuspid valve
Why does the arterial pressure pulse change shape as you go away from heart and how does it change
waveform simpler, smaller, pressure goes down,less evident dichrotic notch. Pressure maintained because lots of energy put into stretching vessels
damping (by elasticity), reflection (interfere with forward compression wave), resonance (pressure wave becomes more complicated)
What causes heart sound
S4-atrial systole rarely heard unless EDP raised)
S1-Lub initiation of V systole and AV valve closure, low freq (primary)
S2-Dup, closure of semilunar valve, higher freq, shorter (primary)
S3-Opening of AV valve, rapid refilling rarely heard except when EDP raised
What can be heard when EDP raised
S3 and S4 as gallop rhythm
What are murmurs and what are they caused by
due to turbulence in blood
valve stenosis or valve regurgitation
how does tricuspid regurgitation alter JVP
v wave is enhanced as ventricular contraction ejects blood through incompetant tricuspid valve hence raising RA pressure and JVP in this phase
