Aortic Stenosis 01.15 Flashcards
3 main causes of Aortic Stenosis
- Congenital (bicuspid valve)
- Rheumatic fever - damages & thickens valves
- Age & degeration
2 physiological LH changes due to AS
LVH
LH dilatation and failure
3 core symptoms of AS (often present late)
SAD
Syncope (exercise related)
Angina
Dyspnoea
6 signs of AS on examination
- Split 2nd heart sound
- Harsh ejection SM
- “Thrusting” apex beat (LVH)
- Narrow pulse pressure
- Small vol and slowly rising carotid pulse
- Ejection “click)
Williams syndrome, Heydes syndrome, Coarctation of aorta, Turners syndrome, PDA and Aortic root dilatation are all associated with what physiological cause of AS
Bicuspid valve - usually presents in 40-50yo
Mean gradient press >40mmHg
Jet velocity >4.0 m/s
Valve area <1.0cm2
Is this mild, mod or sev AS?
Severe - pressure high, force of flow high, valve large
“Ross” procedure - uses a combination of auto graft and homo graft - explain
“Autograft” - use own pulmonary valves to replace AVs, then replace pulmonary valve with cadaver “homograft” valves
what is a TAVI
Trans catheter Aortic Valve Implant - Via femoral artery, balloon expand to insert bovine tricuspid valves
What is laplace’s law and how does it relate to heart physiology
P=T/r (pressure = Tension / radius) i.e. as incr pressure in a sphere - need to incr wall thickness to maintain stable stress (otherwise wall will burst) - as you incr blood pressure, heart / artery wall thickness will incr in response - probs with LVH / vascul probs.
What is starling’s law of the heart (the Frank-Starling )
Increase in PRELOAD (=end diastolic vol, i.e. vol when LV is FULL), this stretches hrt muscle, this increases contractile force (due to increased efficiency of muscle actin fibres conn. to myosin heads) so increased STROKE VOLUME in LV.
Why do you get a split 2nd hrt sound in AS?
Narrow AV so takes longer to empty LV during systole, so you hear PV close first then AV close 2nd.
On a graph of central venous pressure (CVP) what is happening at the a wave
A = Atrium contracts
On a graph of central venous pressure (CVP) what is happening at the c wave
C = TriCuspid valve closes (bulges back into atrium causing slight incr in press wave)
On a graph of central venous pressure (CVP) what is happening at the v wave
V - Atrial filling against closed triuspid Valve - if tricuspid regurge get a BIG V wave
On a graph of central venous pressure (CVP) what is happening at the x descent
Atrium relaXes (ventric systole)
