Lecture 14: Cardiac valve disorders Flashcards
Pathophysiology of aortic regurgitation - PV loop
Low pressure filling
Tremendous preload, diastolic volume doubles
Filling is prolonged (filling from two spots)
Big stroke volume
Slightly enhanced contractility
See figure
What happens to semilunar valves during ventricular systole?
Opening of semilunar valves
Ventricles contract and force the valves to open by pushing blood through
See figure
Aortic valve
See figure
Systole: cusps forced open
Diastole: blood gets caught in valves, and they close
What type of murmur occurs in mitral regurgitation
Holosystolic high pitched murmur extending from S1 to S2
Constant intensity throughout
Heard best at the apex, often radiates to the left axilla
Exaggerated with exertion
What might you hear in the lungs in a person with mitral stenosis?
Rales (crackles)
Due to fluid getting pushed into the lungs
Etiology of mitral stenosis
1) Most commonly occurs a decade after rheumatic fever.
2) Calcification.
3) Congenital.
4) Rarely occurs with lupus (autoimmune) or rheumatoid arthritis.
Sound of murmur in aortic stenosis
Harsh and rough
Crescendo and decrescendo
If the valves ares still malleable, an early ‘clink’ will be heard
A fourth heart sound (S4) is common
What happens if heart failure is present in mitral regurgitation?
Third heart sound
Symptoms of aortic stenosis
1) Angina Pectoris (chest pain): Increased demand for coronary blood due to hypertrophy and afterload. Compression of coronary vessels and the aortic ‘jetstream’ have also been implicated.
2) Syncope (fainting): Due to decreased cerebral flow.
3) Congestive heart failure: Due to persistent afterload.
Why do palpitations occur in people with mitral stenosis?
Usually the results of atrial arrhythmias, such as atrial fibrillation.
The enlarged atrium is the major risk for this, which occurs due to the high atrial pressure.
Dilated atria = electrical path length is longer than usual = increased chance that something will go wrong with transmission of electrical current
What does aortic stenosis cause?
Systolic murmur
Increased pressure required by LV = myocardial hypertrophy
Symptoms of aortic regurgitation?
Shortness of breath
LV is preloaded from the LA and the aorta = increased volume load on the heart
Pressure builds up in the lungs
Pulmonary congestion and edema
Aortic regurgitation anatomy
Retracted fibrotic valve cusps = incompetent aortic valve
Dilated and hypertrophied left ventricle (eccentric hypertrophy)
Symptoms of mitral stenosis
1) Shortness of breath, hemoptysis (coughing of blood or blood stained mucous from respiratory system), and orthopnea (shortness of breath when lying flat)
2) Palpitations
3) Neurological symptoms:
Other physician findings in aortic regurgitation
Widened pulse pressure with hyperdynamic pulses.
Pulsating carotid impulses and nailbeds, sometimes uvula.
What is another word for mitral prolapse? When is it diagnosed?
Floppy mitral valve
Often diagnosed in adulthood, since manifestations can take years to manifest.
Where is a murmur from aortic best heard?
Base of the heart (2nd ICS)
Can project up the carotid
What determines blood flow in the heart?
Changes in pressure
Cause valves to open and close
Blood moves from high pressure to low pressure (gradient)
What are cardiac murmurs? Cause?
Abnormal sounds created by the heart.
Can be caused by pericardial rub, fluid overload (due to renal or heart failure), and valve disease (most common)
What can result if a valve failures to close?
Regurgitation
Incompetency
Why do neurological symptoms occur in people with mitral stenosis?
Usually the result of embolic events caused by the atrial arrhythmias.
Pathophysiology of mitral regurgitation - PV loop
Ventricle gets dilated, filled with same blood
Big preload (EDV)
Big filling curve
Isovolumetric filling and contraction are lost
See figure
What kind of murmur does mitral valve prolapse produce?
Presents as mid-systolic clicks, or late systolic murmur.
What is valve stenosis?
Valve fails to open
What characteristics are common in left-sided murmurs?
Pulmonary congestion and dyspnea
Symptoms of mitral regurgitation
1) Shortness of breath, orthopnea, nocturnal dyspnea: Due to pulmonary congestion and edema.
2) Palpitations: Atrial enlargement predisposes to atrial arrhythmias.
How to know if aortic regurgitation has lead to heart failure?
Third heart sound
What happens to AV valves during diastole?
Opening of the AV valves
Blood returning to the heart travels through the atria and forces the AV valves open
The atria contract forcing addition of blood into the ventricles
See figure
Pathophysiology of mitral stenosis - wiggers lewis
Higher LA pressures
Separation between pressures during diastole
Type of murmur in mitral stenosis
Diastolic rumble over the apex
Worsened after exertion
May have opening snap
Aortic Stenosis anatomy
Valve can be either a tricuspid aortic valve that has thickened and become stenotic, or a bicuspid valve, which results from the fusion of two leaflets of the valve during development
Hypertrophy of left ventricle (concentric hypertrophy)
Post-stenotic dilation of ascending aorta
Calcified aortic valve
See figure
What causes valve disorders?
Infection
Post-infection
Inflammatory disorders
Ischemic disorders
Congenital disorders
Eitology of mitral regurgitation
1) Acute causes: rupture of a chordae or damage to a papillary muscle from ischemia, trauma, or infective endocarditis.
2) Rheumatic heart disease.
3) Myxomatous degeneration (ie. Mitral valve prolapse).
4) Calcification of the annulus.
5) Congenital
Pathophysiology of aortic stenosis: Wiggers-Lewis
Big separation of LV pressure and aortic pressure (LV pressure needs to increase to get the blood through the stenotic aortic valve)
Shortening of pulse pressure
QRS complex is wider (hypertrophy)
Phonocardiogram shows systolic murmur
What is the Gallaverdin phenomenon?
If aortic stenosis is heard at the apex of the heart, it can be confused with mitral regurgitation
What causes shortness of breath, hemoptysis and orthopnea in people with mitral stenosis
Backpressure to the lungs is very severe, which elevates pulmonary capillary pressures.
Pathophysiology of mitral stenosis - PV loop
Can’t get blood into the ventricle = restricted filling
Rheumatic aortic stenosis - how?
Fibrosis and calcification following a strep infection
Pathophysiology of mitral regurgitation - wiggers lewis
High LA pressure
Aortic pressure is normal
See figure
Possible etiologies of aortic stenosis
Congenital
Rheumatic
Degenerative
What is the ethology of aortic regurgitation?
Cups abnormalities: Endocarditis, Rheumatic disease (post infection), Ankylosing spondylitis (systemic inflammatory disease), Congenital malformation
Aortic disease: Aneurysm (blood filled bulge on a vessel), Marfan’s (genetic disease in which connective tissue deteriorates around the aorta and the valve opens), Systemic inflammatory disease, Trauma, Dissection
Phonograms for common murmurs
See figure
Valve anatomy
See figure
Anatomy of mitral stenosis
Small mitral orifice (cusps calcified together)
Atria are not strong enough to push blood through the valve = atria dilate
Enlarged thickened left atrium
Small left ventricle
Thickened matted chordae tendinae
See figure
Where do valve disorders often occur?
Occur more frequently on the left side of the heart
Right valve disorders occur in people who use IV drugs (bacterial deposits)
Congenital aortic stenosis - anatomy of valve, when does it present?
Unicuspid or bicuspid valve
Can present early in life or in 5th-6th decade
What do valve disorders result from
If there is failure of a valve opening or closing
What does mitral valve prolapse lead to?
Occasionally, MVP causes symptomatic regurgitation which increases the risk of infective endocarditis and requires surgical repair.
Degenerative aortic stenosis - how? when? Risk factors?
Calcification of a valve
Usually in 7th decade of life
Risk factors are the same as atherosclerosis
Wiggers/Lewis diagram
Illustrates the relationship between cardiac pressures, volumes, ECG and heart sounds throughout the cardiac cycle
See figure
Types of artificial valve replacements
1) caged ball valve
2) tilting disc valve
3) single leaflet valve
4) bileaflet valve
See figure
Anatomy of mitral regurgitation
Incompetent mitral valve
Retracted shortened mitral valve cusps
Enlarged left atrial appendage
Ruptured chordae tendinae
Enlarged left ventricle
Enlarged left atrium
What type of murmur in aortic stenosis? When does it occur?
Systolic murmur
Begins after S1 and ends before S2
What happens to AV valves during ventricular systole?
Closing of AV valves
Ventricles contract, forcing blood against AV valves
AV valves close (first heart sound)
Papillary muscles contract to stabilize the valves
See figure
What kind of murmur does aortic regurgitation produce
Diastolic murmur in aortic area
Sometimes at apex (austin flint murmur)
Described as blowing and often faint
Where is the apical impulse in a person with mitral regurgitation?
Laterally displaced and hyper dynamic
What does aortic regurgitation cause?
Diastolic murmur
Increased volume load on LV = dilation
How is mitral valve prolapse diagnosed?
Often diagnosed by echocardiogram before symptoms.
Pathophysiology of aortic stenosis: PV loop
Hypertophied LV
Curve is shifted up, the heart is filling under higher pressure
Loop is more narrow (ventricle is hard to fill)
Need to generate big pressure during isovolumetric contraction
Not as much blood is injected into the aorta, so the end systolic volume is higher
Shift in contractility due to SNS stimulation
See figure
Pathophysiology of aortic regurgitation - wiggers Lewis
Diastolic pressure in aorta is low (ejected blood is leaking back into atria)
Widening of pulse pressure
Phonocardiogram: diastolic murmur (always), sometimes accompanied by small systolic murmur
What happens to semilunar valves during diastole?
Closing of semilunar valves
Ventricles relax, intraventricular pressure falls and blood flows back from the arteries, filing the cusps of the semilunar valves, forcing them to close
See figure
