Valvular Heart Diseases Flashcards
What causes rheumatic fever?
Immunologic response to acute streptococcal pharyngitis, Cross-reacivity between streptococcal antigen and structural glycoprotein. Leads to chronic rheumatic valvular heart disease
Criteria for diagnosis of Rheumatic Fever
Jones criteria
Joints - migrating polyarthritis
Carditis
Nodules - subcutaneous nodules in flexor compartment
E- Erythema marginatum (rash with advancing edge and clearing center)
S-Sydenham’s Chorea
Minor criteria include migratory arthralgia, fever, increased APR, and prolonged PR interval
Signs of streptococcal infection
Antistreptolysin O antibodies, positive throat culture
Treatment of Rheumatic Fever
Penicillin
Aspirin/corticosteroids
Treatment of complications
Prevention of Rheumatic Fever
Penicillin G/amoxicillin/azithromycin
What is mitral stenosis
Obstruction of LV inflow that prevents proper filling during diastole.
Normal Mitral valve area and area in stenosis?
4-6 cm normal
less than 2 is stenosis
Common causes of mitral stenosis
Rheumatic heart disease is most common
Infective endocarditis
Annular calcification
Congenital
What happens in the heart during mitral stenosis
Normally there is no pressure difference between the LA and LV, but with mitral stenosis, LA is higher pressure. LV pressures are normal, but because there is reduced filling, SV and CO may decrease.
Symptoms of mitral valve stenosis
Congestion and dyspnea because elevated pressures of LA will cause fluid to back up in the lungs. Also hemoptysis
What does the severity of MS depend on
Degree of reduction in valve area.
MS heart sounds
Loud S1 best heard at apex (occurs because high pressure difference in LA and LV keeps leaflets far apart).
Opening Snap - Follows S2. Sound of the stenotic leaflets snapping open. Followed by diastolic rumble of blood rushing past stenotic leaflets (decrescendo). Best heard at apex. Best heard with the patient lying on the left side in expiration.
Sounds like lub-butter
How does mitral stenosis cause afib?
Dilated LA messes up conduction system.
How to treat MS medically?
Medical therapy doesn’t prevent progression. Can give B blockers, ca channel blockers, digoxin to control HR and prolong diastole for improved filling. Can also give diuretics with fluid overload.
Surgery for MS?
Percutaneous balloon mitral valvuloplasty.
Causes of mitral regurgiation
Rheumatic heart disease, infective endocarditis, degeneration. Dilation/calcification of annulus. Problems with the chordae tendinae (break), CAD involvement of papillary muscle.
What happens in the heart with mitral regurgitation?
A portion of the LV stroke volume is ejected back into the LA. Therefore SV decreases, LA will dilate, hypertrophy of the LV because normal venous return plus regurgitated blood comes into it during diastole.
Does LV SV increase with MR?
Yes, because preload increases.
Hemodynamic profile of MR?
Tall LA V wave because blood rushes back into atria during systole.
Acute MR
Normal LA size and compliance so regurgitation causes increased pressure. This backs up and causes congestion.
Chronic MR
Dilated LA, so pressure doesn’t elevate much. Normal LA and pulmonary venous pressures, but decrease in CO because blood will regurgitate into low-pressure LA. So fatigue weakness ensue. Eccentric hypertrophy occurs.
Mitral regurgitation heart sounds
Holosystolic murmur (between S1 and S2). Chronic sounds like “wow-duh.” S3 frequently present in acute.
How can you increase the murmur from mitral regurgitation?
Breathe out, squeeze hands, squat. This is how you distinguish from aortic stenosis.
How to manage acute MR?
Reduce afterload, which will increase CO and decrease regurg. Diuretics. Emergency surgery.
How to manage chronic MR
Vasodilators (for HTN). Mitral valve repair.
How to check if mitral regurgitation is occurring?
Use echo, can see using cardiac cath. Look for cardiomegaly on chest CR.
Etiology of mitral valve prolapse
Can be familial, or associated with marfans/other connective disorder.
What happens with mitral valve prolapse?
Valvular leaflets enlarge and prolapse into LA during systole.
Symptoms of MP?
Generally asymptomatic, but can cause chest pain or palpitations sometimes.
Chest sounds of Mitral valve prolapse
Midsystolic click, late systolic murmur heard best at apex. Decreased by squatting, increased by valsalva, standing, and handgrip. “Do-phew-do”
How to investigate MP? How to treat?
Echo! Usually benign, so no treatment, but watch for rupture of chordae, which can cause acute MR.
Aortic stenosis size guidelines?
Normal size 3-4 cm
Symptoms occur when valve is ~1cm
Cause of aortic stenosis?
Congenital
Degenerative calcification
Rheumatic heart disease
Under 70 yo, 50% genetic.
Over 70 yo, 50% degenerative
What happens in the heart during aortic stenosis
Pressure gradient develops between the left ventricle and aorta (increased afterload). Therefore, LV will hypertrophy (concentric) to compensate. However, compensatory mechanisms can exhaust and LV function will decline.
What happens to LA during aortic stenosis?
LV will hypertrophy and become thick, so LA needs to hypertrophy too.
Why does AS result in angina?
Imbalance between myocardial oxygen demand and supply. Demand up because of hypertrophy. Supply decreased because of reduced perfusion of myocardium due to increased diastolic pressure of LV.
What else does AS cause?
DOE, Syncope, CHF (later in disease as LV hardens), sudden death.
AS heart sounds
Systolic ejection murmur (crescendo-decrescendo), peaks as stenosis increases. S4 gallop due to LVH.
Pulsus tardus
Slow rising carotid pulse (late after contraction)
Pulsus parvus
Decrease in pulse amplitude.
Prognosis of AS
Really bad, 2 yr-6mo if valve not replaced.
Most valuable test for AS
Echo.
Grading Aortic Stenosis
Based on valve area, mean gradient, and jet velocity. If area is less than 1.5, mild. Moderate is 1.0-1.5. Severe is less than 1.0
Is medical treatment of AS effective?
Not really. In fact, vasodilators are contraindicated.
Most common causes of aortic regurgitation?
Diseases of aortic leaflets, dilatation of the aortic root.
What phase of the cardiac cycle does aortic regurgitation occur?
Diastole
What happens in the heart during AR
Blood comes back into LV during diastole, so LV has to pump that blood and blood from the LA during systole. It therefore augments stroke volume because of the increased preload.
Factors that influence the severity of AR
Size of the regurgitant orifice, pressure gradient across the valve during diastole, duration of diastole.
What happens in acute AR?
LV is normally sized and is noncompliant, so volume load of the AR causes LV diastolic pressure to rise. This will back up to the LA and pulmonary circulation –> dyspnea and edema.
Is acute AR an emergency?
yes! Surgical emergency.
What happens in chronic AR?
LV compensates with eccentric hypertrophy, which causes dilation. So more volume can be added without an increase in diastolic pressure (so less backflow). However, this causes aortic (and systemic arterial) diastolic pressure to drop. But systolic pressure is high because of increased preload. So huge pulse pressure (which is the hallmark). Late stage, more remodeling of LV occurs, and compensation stops working. So forward and eventually backward heart failure.
Hallmark of aortic regurgitation?
Increased pulse pressure.
Symptoms caused by chronic AR
Diastolic pressure drops so coronary artery perfusion pressure falls, decreasing myocardial oxygen supply. This could cause angina even without atherosclerotic coronary disease.
Clinical manifestations of AR
DOE, fatigue, forceful heartbeat due to increased pulse pressure.
Examination of AR shows
bounding pulses from pulse pressure. Hyperdynamic LV impulse. Blowing AR diastolic murmur.
Murmur in AR
Blowing diastolic murmur at left sternal border. Best heard leaning forward after exhaling. Accompanied by mid-diastolic rumbling –>Austin Flint murmur. Also with systolic ejection murmur due to increased flow across the aortic valve.
How to treat AR
Decrease afterload with ACEI.
