Valvular Disorders Flashcards
What are the four valves of the heart?
- Tricuspid
- Mitral
- Pulmonary
- Aortic
What two pathologies do valvular lesions generally result in?
Stenosis (decreased caliber of the valve orifice) or regurgitation
What is Acute Rheumatic Fever?
Systemic complication of pharyngitis due to group A beta-hemolytic streptococci
When does Acute Rheumatic Fever occur? Who does it target?
Affects children 2-3 weeks after an episode of streptococcal pharyngitis (“strep throat”)
What causes Acute Rheumatic Fever?
Molecular mimicry
-Bacterial M protein resembles proteins in human tissue (meromycin)
What is diagnosis of Acute Rheumatic Fever based upon?
Jones Criteria
What are the Jones Criteria (generally)?
-Evidence of prior group A beta-hemolytic streptococcal infection (e.g., elevated ASO or anti-DNase B titers) with presence of major and minor criteria.
What are the minor Jones criteria?
Non-specific and include:
- Fever
- Elevated ESR
What are the 5 major Jones criteria?
- Migratory polyarthritis
- Pancarditis
- Subcutaneous nodules
- Erythema marginatum
- Sydenham chorea
What is Migratory polyarthritis?
Swelling and pain in a large joint (e.g. wrist, knees, ankles) that resolves within days and “migrates” to involve another large joint
What is Pancarditis?
All three layers of heart inflamed
- Endocarditis
- Myocarditis
- Pericarditis
What is involved in ARF endocarditis?
- Mitral valve is involved more commonly than aortic valve.
- Characterized by small vegetations along lines of closure that lead to regurgitation
What is involved in ARF myocarditis?
-Aschoff bodies that are characterized by foci of chronic inflammation, reactive histiocytes with slender, wavy nuclei (Anitschkow cells), giant cells, and fibrinoid material
What is the most common cause of death during the acute phase of rheumatic fever?
Myocarditis!
What do Aschoff bodies contain?
Anitschkow cells (caterpillar nucleus)
What is involved in ARF pericarditis?
Leads to friction rub and chest pain
What is erythema marginatum?
Annular, nonpruritic rash with erythematous borders, commonly involving trunk and limbs
What is sydenham chorea?
Rapid, involuntary movements
What may happen with longer term Acute Rheumatic Fever?
- Acute attack usually resolves
- May progress to chronic rheumatic heart disease
- Repeat exposure to group A beta-hemolytic streptococci results in relapse of the acute phase and increases risk for chronic disease
What is chronic rheumatic heart disease?
-Valve scarring that arises in consequence of rheumatic fever
What does the valve scarring of chronic rheumatic heart disease result in?
Stenosis with a classic ‘fish-mouth’ appearance
What does Chronic Rheumatic Heart disease almost always involve?
Mitral Valve
–> this leads to thickening of the chordae tendineae and cusps
What does Chronic Rheumatic Heart disease occasionally involve?
Aortic Valve
–> leads to fusion of the commissures
What valves are involved in Chronic Rheumatic Heart disease?
Mitral and Aortic
-Other valves are less commonly involved
What is the major complication of chronic rheumatic heart disease?
Infectious endocarditis
What is the pneumonic for the major JONES criteria?
J - joint, migratory polyarthritis O - heart problems (endo, myo, peri) N - subcutaneous nodules E - erythema marginatum S - sydenham chorea
What is aortic stenosis?
Narrowing of the aortic valve orific
What causes aortic stenosis?
Usually due to fibrosis and calcification from “wear and tear”
When does aortic stenosis present?
Late adulthood (>60 years)
What hastens disease onset for Aortic Stenosis?
Bicuspid aortic valve (two cusps doing the work of one!)
- It also increases risk
- A normal aortic valve has three cusps and fewer cusps results in increased “wear and tear” on each cusp
What may Aortic Stenosis arise as a complication of?
Chronic Rheumatic Valve disease
-It usually coexists with mitral stenosis
What trait distinguishes rheumatic fever aortic stenosis from normal “wear and tear”?
Fusion of the aortic valve commissures
What happens during the asymptomatic stage of Aortic Stenosis?
- Cardiac compensation is what leads to this prolonged asymptomatic stage
- A murmur can be heard!!
What murmur is heard for Aortic Stenosis?
Systolic ejection click followed by a crescendo-decrescendo murmur
What are three complications of Aortic Stenosis?
- Concentric left ventricular hypertrophy - may progress to cardiac failure
- Angina and syncope with exercise
- Microangiopathic hemolytic anemia
What causes angina and syncope with exercise in Aortic Stenosis?
Limited ability to increase blood flow across the stenotic valve leads to decreased perfusion of the myocardium and brain
What causes microangiopathic hemolytic anemia in Aortic stenosis?
RBCs are damaged (producing schistocytes) while crossing the calcified valve.
What is the treatment for Aortic Stenosis?
Valve replacement after onset of complications
What is Aortic Regurgitation?
Back flow of blood from the aorta into the left ventricle during diastole.
What causes Aortic Regurgitation?
Arises due to aortic root dilation (e.g. syphilitic aneurysm and aortic dissection) or valve damage (eg infectious endocarditis)
What is the most common cause of Aortic Regurgitation?
Isolated root dilation (sometimes from aortic aneurysm)
What murmur is caused by Aortic Regurgitation?
Early, blowing diastolic murmur (caused by the blood flowing backward across the valve)
What are the clinical features of Aortic Regurgitation?
- Murmur
2. Hyperdynamic circulation due to increased pulse pressure!
Why is there an increased pulse pressure with aortic regurgitation?
-Diastolic pressure decreases due to regurgitation, while systolic pressure increases due to stoke volume
What symptoms does a patient with Aortic Regurgitation present with?
- Bounding pulse (water-hammer pulse)
- Pulsating nail bed (Quincke pulse)
- Head bobbing
What does Aortic Regurgitation cause?
- LV dilation
- Eccentric hypertrophy (due to volume overload)
What is the treatment for Aortic Regurgitation?
Valve Replacement once LV dysfunction develops
What is Mitral Valve Prolapse?
Ballooning of mitral valve into left atrium during systole
What percentage of US adults have Mitral Valve Prolapse?
2-3%
What causes Mitral Valve Prolapse?
Myxoid degeneration (accumulation of ground substance) of the valve making it floppy.
What is the etiology of Mitral Valve Prolapse?
Unknown
-May be seen in Marfan syndrome or Ehlers-Danlos syndrome
What type of murmur does MVP usually present with?
- Incidental mid-systolic click (opening a paracheute) followed by a regurgitation murmur
- Usually asymptomatic
What happens if a patient with MVP squats?
-Click and murmur will become softer with squatting (increased systemic resistance decreases left ventricular emptying)
What complications are associated with Mitral Valved Prolapse?
- Infectious Endocarditis
- Arrhythmia
- Severe Mitral Regurgitation
What is the treatment for Mitral Valve Prolapse?
Valve Replacement
What is Mitral Regurgitation?
-Reflux of blood from left ventricle into the left atrium during systole
What usually causes Mitral Regurgitation?
Usually arises as a complication of mitral valve prolapse
-Other causes include LV dilation (e.g. left sided cardiac failure), Infective Endocarditis, Acute Rheumatic Heart Disease (this disease prefers mitral valve), papillary muscle rupture after MI
What murmur is associated with Mitral Regurgitation?
Holosystolic “blowing” murmur
When does the Mitral Regurgitation murmur get louder?
- Louder with squatting (increased systemic resistance decreases left ventricular emptying)
- Expiration (increased return to left atrium)
What does Mitral Regurgitation result in long term?
Volume overload and left-sided heart failure
What is mitral stenosis?
Narrowing of mitral valve orifice
What usually causes mitral stenosis?
Chronic rheumatic valve disease (prefers mitral valve)
What murmur is associated with mitral stenosis?
Opening snap followed by diastolic rumble
What damage does volume overload cause in mitral stenosis?
Dilation of the left atrium
What does dilation of the left atrium cause in mitral stenosis?
- Pulmonary congestion with edema & alveolar hemorrhage
- Pulmonary hypertension and eventual right-sided heart failure
- Atrial fibrillation with associated risk for mural thrombi
