The Cardiac Cycle Flashcards
What do pressure-volume loops graphically represent?
Ventricular pressure against ventricular volume during a single cardiac cycle.
What do the X2 straight lines on the pressure-volume loops represent?
Isovolumetric events (contraction and relaxation)
What does the measurement from left to right horizontally across the pressure-volume loop tell us?
The stroke volume, from which we can calculate an ejection fraction.
What does the area of the loop tell us?
Stroke work
Is jugular venous pressure monophasic or biphasic, and what do these terms mean?
It is biphasic (X2 pulses per trace cycle)
Monophasic = X1 pulse (such as an arterial trace)
What X5 letters correspond to the X5 phases of a jugular venous pulse?
A C X V Y
What does the A phase represent?
Atrial contraction - no valves between JV and RA will see a rise in pressure (pulse 1)
What does the C phase represent?
Carotid pulse - will ‘throb’ as ventricle contracts and distend against the JV (a small dicrotic style notch on pulse 1 will be seen graphically)
What does the X phase represent?
Atrial relaXation - will see pulse 1 (on the trace) drop as the JV pressure drops
What does the V phase represent?
Atrial filling during Ventricular systole - as the ventricle is still contracting/ed the atria relax and passively fill. The tricuspid valve bulges and a second pulse is seen on the trace.
What does the Y phase represent?
Passive atrial emptYing - ventricles relax and fill as atria passively empty. The trace of pulse 2 therefore drops as the pressure does.
How would you measure JVP and what do the numbers mean?
Lie patient @ 45 degrees and measure the height of the jugular vein before it collapses from the angle of Louis.
> 3cm = pathological.
What would tricuspid valve stenosis look like on a JVP trace?
High A wave
Low V wave
What would tricuspid valve regurgitation look like on a JVP trace?
Low A wave
High V wave
