Exam 2: Lecture 1 (Kirk) Flashcards
Under normal circumstances:
The aortic valve has ______ leaflets
The mitral valve has ______ leaflet
Aortic valve has three leaflets
Mitral valve has 2 leaflets
What is the basic difference between
a stenotic valve
a insufficient valve
A stenotic valve is a valve that doesn’t open all the way
An insufficient valve is a valve that doesn’t close all the way
What are some important vessels that branch off the aorta?
The coronary arteries branch off the aorta
Major Causes of Aortic Stenosis?
Explain the term “senile aortic stenosis” and what it is caused by
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Senule Aortic Stenosis is essentially caused by atherosclerosis.
- Cellular proliferation of valve interstitual cells (builds up where leaflets connect)
- Lipid accumulation
- Inflammation with monocyte/macrophage infiltration of valve leaflets
- Valvular calcification and fusion of the leaflets is predominant
Explain the causes begind a cogenitially deformed aortic valve?
Congenitally deformed aortic valves may have turbulent flow as the major cause of endothelial disruption, matrix _____, and _____ deposition
Congenitally deformed aortic valve:
malformed during development, most commonly 2 leaflets instead of 3 (aka bicuspid aortic valve)
Congenitally deformed aortic valve: may have turbulent flow as the major cause of endothelial disruption, matrix deposition, and calcium deposition
Explain how Acute Rheumatic Fever can cause aortic valve stenosis
Rheumatic aortic valve inflammation, bubrosis, and calcification following ARF caused by strep throat and scarlet fever
Rheumatic Aortic Stenosis:
endocardial inflammation followed by calcification (as in the mitral version as well)
aka inflammation of the endocardial tissue can cause inflammation of the valve itself and cause calcium to collect there
Pathophysiology of Aortic Stenosis:
- Normal aortic valve orifice is _____ cm2
- As valve becomes stenotic, lefleats _____ and the open valve area is _____
- When valve area is reduced by ___%, elevated LV pressure during systole is required to drive blood across the narrowed opening
Pathophysiology of Aortic Stenosis:
- Normal aortic valve orifice is 3-4 cm<strong>2</strong>
- As the valve becomes stenotic, leaflets fuse and the open valve area is reduced
- When the valve area is reduced by 50%, elevated LV pressure during systole is required to drive blood across the narrowed opening
Pathophysiology of Aortic Stenosis:
- Aortic stenosis developes ______
- LV can compensate for the narrowed orifice by undergoing ____________ in response to the pressure overload
Pathophysiology of Aortic Stenosis:
- Aortic Stenosis develops gradually (even patients with bicuspid valves develop significant AS only in their 40-50’s).
- The LV can compensate for the narrowed orifice by undergoing concentric left ventricular hypertropy (LVH) in response to the pressure overload
Ventricular Remodeling in Pressure-Overload Induced LVH:
- Increases systolic wall stress induces a ________ in cardiomyocytes
- Cell increase in width by ______
Aortic Stenosis: Ventricular Remodeling in Pressure-Overload Induced LVH
- Increased systolic wall stress induces a growth response in cardiomyocytes
- Cell increase in width by adding additional sarcomeres in parallel
- The increased myocyte width accounts for most of the increase in wall thickness
Ventricular Remodeling in pressure-overload induced LVH:
- Both LVH and fibrosis increase passive myocardial stiffness, reducing _______ during the passive filling phase, eventually causing an increase in ______
Left atrium also undergoes hypertrophy in response to elevated ___
Increased wall stiffness places increased burden on LA contraction to fill LV _____
- Both LVH and fibrosis increase passive myocardial stiffness, reducing ventricular compliance during passive filling phase, eventually causing an increase in left ventricular end diastolic pressure (LVEDP)
- Left atrium also undergoes hypertrophy in response to elevated LVEDP
- Increased wall stiffness places increased burden on LA contraction to fill LV at the end of diastole (greater reliance on LA “kick”)
What are some clinical signs of patients with significant Aortic Stenosis?
Clinical presentations of patients with hemodynamically significant Aortic Stenosis:
Exertional Angina, Exertional Syncope, Excertional Dyspnea
If the aortic stenosis gets bad enough and goes untreated, it can become Congestive Heart Failure
Symptoms are related to valve area in aortic stenosis:
- Normal Valve area is ______
Symptoms in aortic stenosis
- _______: usually no symptoms
- ______ mild AS
- _______ severe AS
Symptoms are related to valve area in aortic stenosis:
- Normal Valve area is 3-4 cm2
- Symptoms in Aortic Stenosis:
- > 2 cm2 : usually no symptoms
- 1.5-2.0 cm2 : Mild AS
- < 1.0 cm2: Severe AS
Pathophysiology of Angina with Aortic Stenosis:
- Increased systolic wall stress _____ myocardial O2 consumption
- Hypertrophied LV requires _______
- Rising LVEDP, does what to the coronary arteries?
Pathophysiology of Angina with Aortic Stenosis:
- Increased systolic wall stress increases myocardial O2 consumption
- Hypertrophied LV requires more O2 nutrients
- Rising LVEDP, especially during exercise, reduces flow gradient by compressing subendocardial vasculature and reducing Coronary blood flow
HENCE WHY CHEST PAIN DURING EXERTION
Pathophysiology of Syncope in Aortic Stenosis:
- Fall in Cardiac Output with Exercise:
- stenotic aortic valve limits ability to ________
- exercise also causes a reduction in ________
- Combination of these two lead to a ________ in BP with exercise
- Results in exercise- induced syncope
Fall in Cardiac Output with Exercise:
- Stenotic aortic valve limits ability to increase cardiac output during exercise
- Exercise also causes a reduction in systemic vascular resistance
- Combination leads to DECREASE in blood pressure with exercise
Results in exercise induced syncope
CHF in AS:
- Abnormally increased LA pressure causes ______
- LVH also causes an impairment in _____, contributing to heart failure
- AS is a potential cause of HF with ________
CHF in Aortic Stenosis:
- Abnormally increased LA pressure causes backward transmission of pressure into pulmonary venous system
- LVH also causes impairment in LV diastolic function, contributing to heart failure
- AS is a potential cause of HF with Preserved Ejection Fraction (Diastolic HF)
Hemodynamics in AS:
Explain the difference in the PV loop and the wigger’s diagram for patients with Aortic Stenosis?
What happens to Left Ventricle Pressure curve?
Any other findings on the Wigger Diagram?
What happens to the PV loop?
Wigger Diagram: increase in LVP curve due to stenotic valve, greater reliance on atrial kick to fill LV during diastole, new presence of a systolic murmur
PV Loop: Increased EDP, Increased Afterload, Increased contractility
Physical Findings in Aortic Stenosis:
- __________murmur
- Evidence of ____ (systolic heave)
- Abnormal ____ pulse
- Loud ____
- Reduced or absence of ____
Physical Findings in Aortic Stenosis:
- Systolic ejection murmur
- Evidence of LVH (systolic heave)
- Abnormal carotid pulse
- Loud S4
- Reduced or absent aortic component of S2
Explain what TAVR is… what does it fix?
TAVR stands for Transcatheter Aortic Valve Replacement (TAVR)
They put in a catheter through an artery, go into aortic valve, put in a baloon etc
TopHat Question:
How does the heart compensate to gradual development of aortic stenosis?
Heart compensates for Aortic Stenosis by “concentric hypertropy”
Note: concentric hypertrophy is a response to pressure overload (stenosis)
Eccentric hypertrophy is a response to volume overlaod
Explain the basic nature of aortic insufficiency/ regurgitation and then list the four classifications of AR
Basic explanation: the aortic valve is homehow insufficient in that it allows blood to flow back from the aortic space into the LV
This is classified as:
Acute AR, Chronic AR
Diseases of Aortic Root, or Diseases of Aortic Leaflets
Explain the causes of Aortic Regurgitation in terms of Valve Leaflet Abnormalities vs Dilatation of the Aortic Root
Abnormalities of Valve Leaflets
- Congenital (bicuspid valve)
- Endocarditis
- Rhematic
(endocarditis and rheumatic fever based AR are based on inflammation that affects the aortic valve’s ability to close)
Dilatation of Aortic Root:
- Aortic Aneurysm
- Aortic Dissection
- Syphillis
Pathophysiology of Acute AR:
- In Acute AR there is _______ of the valvular leak
- In Acute AR, there is _________ for LV remodeling to occur
- In Acute AR, regurgitant volume _________ pressure in LV, causing _______ in LA and therefore causing ________
Acute AR:
- In Acute AR, there is rapid development of the valvular leak
- In Acute AR, there is insufficient time for LV remodeling to occur
- In Acute AR, regurgitant volume increases pressure in LV, causing increased pressure in LA, and pulmonary congestion
Pathophysiology of Chronic AR:
- In Chronic AR, there is ____ development of the valvular leak
- In Chronic AR, there is _______ for LV remodeling to occur
- That LV remodeling is called “________”
- In Chronic AR, regurgitant volume increases _______, with less of an increase in _____, and less ______
- Patients remain ________ for a long period
CHRONIC AR:
- In Chronic AR, there is a slow development of the valvular leak
- In Chronic AR, there is time for LV remodeling to occur (volume overload)
- “Eccentric LV Remodeling”
- In Chronic AR, regurgitant volume increases pressure in LV slowly, with less of an increase in LA pressure, and less pulmonary congestion
- Patients remain asymptomatic for a long period of years
Explain the Hemodynamics of Chronic AR;
What are the changes to the Wigger Diagram?
Changes to the PV Loop?
Chronic AR:
Higher LV Pressure (due to more volume)
INCREASED PP
Diastolic Leak
Two heart murmurs: cres/dec and diastolic murmur due to regurgitation
PV Loop: decreased contractility, decreased stiffness, increased SV
What are the two heart murmurs that one would have in with AR?
There are two heart murmurs that someone would hear in a patient with Aortic Regurgitation:
- ejecting more volume than normal, increased volume in LV causes “crescendo/decresendo” during systole
- In diastole, blood flow flowing back from aorta into LV causes diastolic murmur due to the regurgitant flow
Physical Findings in Aortic Regurgitation:
All of the physical findinds called “hyperdynamic pulses” are due to _______
Physical Findings in Aortic Regurgitation:
All of these physical findings “hyperdynamic pulses” are due to wide pulse pressure
What are some chest x-ray findings of someone with Chronic AR?
In someone with chronic ar:
LV enlargement (boot shape)
Widened aortic arch
Explain the treatment for Chronic AR
What is a contraindication for chronic ar?
Treatment for Chronic AR:
No treatment at first
Afterload reducing agents (vasodilators), in order for blood to favorably do downstream and not back
Contraindication for IABP
Timing of valver replacement is dependent on rate of LV dilatation
Serior echo’s are used to time valve replacement surgery
Explain how Acute Rhemuatic Fever can cause Mitral Valve Stenosis:
- ARF is an inflammatory condition involving skin, connective tissue, and heart
- ARF- formally a common cause of valvular heart disease in the US, but now rare in western countries, more prevalent in developing countries
- Autoimmune cross reactivity between _______
Acute Rheumatic Fever Causing Mitral Valve Stenosis:
- Autoimmune cross reactivity between bacterial and cardiac antigens
The antibodies that the immune system generates against the protein may cross react with cardiac tissue
Creating an inflammatory response and messing up valves (usually the mitral)
Gross Pathology of Rheumatic Mitral Stenosis:
- Chronic Phase: stenosis and or regurgitation of chronic valves is common
- _______ is most commonly affected
- _____% of patients with rheumatic heart disease develop mitral stenosis
– Additional ___ have mitral stenosis and aortic valve disease
Rhematic Mitral Stenosis:
Mitral valve is most commonly affected
40% of patients with rheumatic heart disease develop mitral stenosis
- Additional 25% have mitral stenosis and aortic valve disease
Pathophysiology of Mitral Stenosis:
- Normal mitral valve orifice is ____
- Mitral stenosis occurs when there is a _______ across the mitral valve during diastole
- Hemodynamically significant mitral stenosis develops with the CSA is reduced to ___
- Reduced CSA causes an abnormal pressure gradient between ____ and _____ during diastole
Pathophysiology of Mitral Stenosis:
- Normal mitral valve orifice is 4-6 cm2
- Mitral stenosis occurs when there is an obstruction to flow across the mitral valve during diastole
- Hemodynamically significant mitral stenosis develops when CSa reduces to < 2 cm2
- Reduced valve CSA causes an abnormal pressure gradient between the LA and LV in diastole
Mitral Stenosis:
Due to the reduced CSA and increase in a pressure gradient between the LA and LV during diastole
LA pressure is ________
Increased LA pressure causes ______ LA diameter, LA _______, and LA _____
Mitral Stenosis:
Due to the reduced CSA and increase in pressure gradient between the LA and LV during diastole
LA pressure is abnormally ELEVATED
Increased LA pressure causes increased LA diameter (dilatation), LA hypertrophy, and LA fibrosis
Pathophysiology of Mitral Stenosis:
- Because of impaired LV filling during diastole, LV stroke volume and CO may _____
- Thus, Mitral Stenosis is a Disorder of _______ and _______
- High LA pressure in LA is passively transmitted to the pulmonary circulation, resulting in ______ pulmonary venous and pulmonary capillary pressures
Pathophysiology of Mitral Stenosis:
- Because of impaired LV filling during diastole, LV stroke volume and CO may be reduced
- Thus, Mitral Stenosis is a disorder of left ventricular filling, and failure of the Left Atrium
- High LA pressure in MS is passively transmitted to the pulmonary circulation, resulting in INCREASED pulmonary venous and pulmonary capillary pressures
Explain the changes in the Wigger Diagram and the PV Loop for Mitral Valve Stenosis
Mitral Stenosis:
Very High Atrial Pressure
Low EDP (reduced filling)
Atrial Kick
Atrial Arrhythmia’s may occur (Afib)
No LV remodelling, so no changes in contractility, just decreased filling
What are some Major Complications of Mitral Stenosis?
What is the treatment of Mitral Stenosis?
Major Complications of Mitral Stenosis
- LA enlargement
- Afib
- clots and stroke
- CHF
Treatments for Mitral Stenosis:
- Treatment of Choice is Balloon Mitral Valvuloplasty
Pathophysiology of Mitral Regurgitation:
- LV contraction during systole normally forces the MV to close
- In MR, the valve __________, causing blood to _________ during systole
- Concenquences of MR therefore include:
Pathophysiology of Mitral Regurgitation:
- LV contraction during systole normally forces the MV to close
- In MR, the valve does not completely close, causing blood to regurgitate back into Left Atrium during Systole
- Concenquence of MR include: increased blood and pressure in LA, reduction in SV and CO, volume related stress on LV, so “volume overload”
Mitral Valve Regurgitation:
- Regurgitant Fraction ______ when LV afterload INCREASES
- Ejected blood volume takes the path of least resistance
Mitral Valve Regurgitaton:
Regurgitant Fraction INCREASES when LV afterload INCREASES
Ejected blood volume takes the path of least resistance
Pathophysiology of Acute Mitral Regurgitation:
- In Acute MR, mitral valve _________
- __________ can develop if Acute MR is severe
Pathophysiology of Acute Mitral Regurgitation:
- In Acute MR, mitral valve suddenly becomes incompetent, allowing for a sudden increase in regurgitant volume
- No time for left atrial compliance to change with a sudden increase in pressure and volume
- No time for left ventricular compliance to change
Acute CHF/ cardiogenic shock can develop if Acute MR is severe
Clinical Presentation and Rx of Acute MR:
- Since there has been no time for any structural remodeling to occur, patients with acute MR often present with _________
- this causes _______ (sound) in both lungs, also ______, ______, ______
How do you treat the above problem?
Clinical Presentation and Rx of Acute MR:
Since there has been no time for any structural remodeling to occur, patients with acute MR often present with acute pulmonary edema
- this causes Rales in both lung fields, cyanosis, frothy blood tinges spetum, extreme air hunger
Treat pulmonary edema with IV diurhetics, afterload reducing agent (nitroprusside to reduce afterload) and dobutamine (increase CO)
Often a surgical emergency
Pathophysiology of Chronic MR:
- In Chronic Mr, mitral valve leak develops ______, allowing for _______ of LA to increased pressure and volume
- In Chronic MR, LV shape and volume _____ to increased handling of both normal pulmonary flow and regurgitant flow
- End result is dilation and increased compliance of ______
Pathophysiology of Chronic MR:
- In Chronic MR, mitral valve leak develops slowly (months to years), allowing for adaptation (structural remodeling) of LA to increased pressure and volume
- In Chronic MR, LV shape and volume also adapts to increase handling of both normal pulmonary flow and regurgitant blood flow
- End result is chamger dilation and increased compliance of BOTH LA and LV
Clinical Presentation of Chronic Mitral Regurgitation:
- What kind of heart sounds would be present with chronic MR?
- What else will be present?
For Chronic MR:
- Apical systolic murmur
- Left sided S3 gallop
- LV enlargement, LV hypertrophy
- Often have AFIb
Explain the hemodynamics of in MR
What happens to wigger diagram and PV loop
Mitral Regurgitation:
Backflow into atria shown on Wigger
PV Loop: decreased contractility, reduced EDP
(this is very similar to AR, also with eccentric hypertrophy)
Remember, eccentric hypertrophy happens with both AR and MR, and due to it, you get reduced contractility and reduced EDP
Treatment of Chronic Mitral Valve Regurgitation:
How do you treat chronic MR?
Treatment of Chronic MR:
- Medical therapy: diurhetics to treat any pulmonary congestion
- Aggressive anti-hypertensive Rx if HTN is present
- Digoxin if Afib is present
- Mitral Valve repair or replacement
