Valvular Disease & Murmurs Flashcards
What is the most common congenital abnormality of the heart?
Bicuspid aortic valve
Occurs in 1-2% of the population
Complications of bicuspid aortic valve
Valvular - aortic stenosis, aortic insufficiency, endocarditis)
Vascular - proximal aortic dilation, aneurysm, dissection
Aortic Sclerosis
Precedes aortic stenosis; valve is sclerotic but no abnormal pressure gradient yet exists between the LA and LV
Aortic stenosis - 3 etiologies
Age-related degenerative/calcific changes
Congenitally deformed aortic valve leading to turbulent flow and gradual endothelial damage and calcification
Rheumatic valve disease
Complications of aortic stenosis
LV hypertrophy in response to increased pressure; LA hypertrophy in response to LVH
Clinical manifestations of aortic stenosis -3
- Angina, due to increased myocardial oxygen demand
- Exertional syncope - ventricle cannot increase its CO during exercise + vasodilation of peripheral mucle beds leads to decreased cerebral perfusion
- Congestive heart failure due to elevation of LA pressure
Signs of aortic stenosis
LV hypertrophy Tall QRS Coarse, systolic ejection murmur S4 sound due to atrial contraction into stiff LV Reduced A2 component of S2
Aortic stenosis - treatment
AV valve dilation - mechanical prosthesis, bioprosthesis, or homograph
Acute aortic regurgitation
The LV is of normal size and relatively non-compliant; therefore, the volume load of regurgitation causes a substantial increase in LV pressure which is transmitted to the LA and pulmonary vasculature, causing congestion
Chronic aortic regurgitation
LV undergoes compensatory eccentric hypertrophy (with dilation) due to volume overload; dilation allows increased compliance of the LV so that it may accomodate a larger regurgitant volume with less pressure increase
Diastolic pressure may decrease; systolic pressure increases due to high LV stroke volume - pulse pressure is high
Aortic regurgitation - treatment
Surgical correction - for symptomatic patients or when EF < 50%
Monitoring + possible benefit of afterload reducing vasodilators (Ca2+ channel blockers, ACEIs) in the setting of HTN
Pulmonic stenosis
Almost always caused by congenital deformity, diagnosed most often in children/adolescents
Transcatheter balloon valvuloplasty is effective treatment
Myxomatous mitral valve disease
Primary mitral valvulopathy associated with connective tissue disease in which normal connective tissue is replaced by mucin
Causes of mitral regurgitation - 2 classifications
- Primary mitral valve disease - myoxomatous, endocarditis, chordae rupture, etc.
- Functional - ventricular dilation, chordae tethering, etc.
What is the major etiolology of mitral stenosis?
Rheumatic Fever - 50%
Passive hypertension
Occurs in the setting of increased LA pressure (2/2 mitral stenosis, for example)
High LA pressure is transmitted backward into the pulmonary vasculature; pulmonary hypertension is obligatory in order to preserve forward flow in the setting of increased LA pressure
Reactive hypertension
Occurs in the setting of increased LA pressure (2/2 mitral stenosis, for example)
Increased arteriolar resistance impedes blood flow into engorged capillary beds, reducing capillary hydrostatic pressure and further edema; however, contributes to RV heart strain
Signs of mitral stenosis
Loud S 1 - caused by mitral valve leaflets slamming shut from a wide position
Diastolic rumble - caused by turbulent flow across the stenotic mitral valve during diastole
Treatment of mitral stenosis
Percutaneous balloon valvuloplasty - “cracks open” fused leaflets
Surgical replacement
Medical treatment to slow rapid ventricular rate, improving fill time (B-blockers, Ca2+ channel blockers, Digoxin) + Diuretics
Mitral regurgitation - Etiologies
Structural abnormality Infective endocarditis Rheumatic fever Calcification Ischemic heart disease / papillary muscle dysfunction LVH
Acute mitral regurgitation
Caused by sudden rupture of chordae tendinae, for example
LA is unadjusted and so uncompliant; regurgitant volume causes a substantial increase in LA pressure which is transmitted to pulmonary circulation
LV accomodates increased volume load returning from the LA via Frank-STarling
Chronic Mitral Regurgitation
LA undergoes compensatory changes - dilates and increases compliance in order to accomodate larger volume; this decreases pulmonary congestion but compromises forward CO because the compliant LA becomes a low pressure “sink” for LV ejection
LA dilation also predisposes to atrial fibrillation
Signs of mitral regurgitation
Apical, systolic murmur
S3 sound - reflects increased volume returning to LV in early diastole
Radiograph shows pulmonary edema in acute MR, more likely to show LV and LA enlargement in chronic MR
Tricuspid Regurgitation - Etiology
90% functional problem with right ventricle, most often enlargement (2/2 pulmonary hypertension)
Primary tricuspid valvulopathy is rare - endocarditis, rheumatic
Signs of tricuspid regurgitation
Systolic murmur along the left lower sternal border that increases with inspiration
V waves in jugular veins - caused by regurgitation of blood from the RV through the RA and into the jugular
Pulsatile liver - caused by regurgitation of RV blood into systemic veins
Physiological split of S2
Audible splitting of A2 and P2 on inspiration
Negative intrathoracic pressure during inspiration induces an increase in venous return from the body into the RA; simultaneously, reduced blood volume returns from the lungs via the LA
Because of increased blood in the RV, the pulmonary valve stays open longer during ventricular systole due to increased emptying time, whereas the aortic valve (A2) closes earlier due to reduction in LV volume and emptying time
Murmur of aortic regurgitation
Murmur represents turbulent back flow of blood from the aorta into the LV during diastole
High pitched, decrescendo, diastolic murmur typically heard best with the diaphragm along the left sternal border
Murmur of aortic stenosis
Harsh systolic murmur followed by a distinct S2 sound, best heard at the 2nd right intercostal space
Murmur of mitral stenosis
Loud S1 due to elevated LA pressure that causes the mitral valve to close under higher pressure
Opening snap after S2 - distinct, crisp sound representing the opening of the stenotic mitral valve
S3
S1-S2-S3 (Ten-ne-ssee)
Low pitched sound; occurs during rapid filling of a pressurized ventricle in early diastole
S4
Late diastolic sound heard due to atrial ejection into a stiffened ventricle
Normal finding in patients > 55
Broadly, what causes systolic murmurs?
Stenosis of the semilunar valves or regurgitation of the atrioventricular valves
Broadly, what causes diastolic murmurs?
Stenosis of the AV valves or regurgitation of the semilunar valves
