VALVULER HEART DISEASE Olcay ZVEREN, M.D.

Aortic Stenosis Aortic stenosis (AS) is defined as the reduction of the orifice of the aortic valve caused by a failure of the leaflets to open fully during systole.Left ventricular outflow obstruction most commonly occurs at the aortic valve, however it can occur above the aortic valve (supravalvular) or below the aortic valve as in hypertrophic obstructive cardiomyopathy (HOCM).

The risk factors of calcific AS Similar to those for vascular atherosclerosis :.elevated serum levels of LDL cholesterol and lipoprotein(a) .Diabetes.Smoking.hypertension.

Rheumatic Aortic Stenosis Rheumatic AS results from adhesions and fusions of the commissures and cusps and vascularization of the leaflets of the valve ring, leading to retraction and stiffening of the free borders of the cusps.Calcific nodules develop on both surfaces, and the orifice is reduced to a small round or triangular opening The rheumatic valve is often regurgitant, as well as stenotic. Patients with rheumatic AS invariability have rheumatic involvement of the mitral valve .

Pathophysiology

LV wall stress is directly proportional to myocardial O2 demand, more specifically: O2 demand = wall stress X HRUsing the above equation, we can understand the pathologic process that develops over many years in patients with aortic stenosis. As LV pressure slowly increases over time due to worsening aortic stenosis, a parallel increase in LV wall thickness occurs (concentric hypertrophy) in order to maintain the LV wall stress at a constant level (since LV wall stress is an important determinant of myocardial O2 demand). Eventually, the LV is unable to hypertrophy any further, but the LV pressure continues to rise as the aortic stenosis worsens. This leads to a rise in LV wall stress and thus a rise in LV myocardial oxygen demand. When the heart rate increases in response to exertion (heart rate is also a determinant of O2 demand), a significant supply versus demand mismatch occurs resulting in myocardial ischemia and the clinical symptoms of angina.

Classification of the Severity of AS

Symptomsexertional dyspnea (LV diastolic dysfunction, with an excessive rise in end-diastolic pressure leading to pulmonary congestion and the limited ability to increase cardiac output with exercise )Angina (precipitated by exertion and relieved by rest. Angina results from the combination of the increased oxygen needs of hypertrophied myocardium and reduction of oxygen delivery secondary to the excessive compression of coronary vessels )Syncope (reduced cerebral perfusion that occurs during exertion when arterial pressure declines consequent to systemic vasodilation in the presence of a fixed cardiac output , MAP = CO X TPR)heart failure symtoms

Physical Examination parvus and tardus carotid impulse (slow-rising, late-peaking, low-amplitude carotid pulse . However, in patients with associated AR or in older patients with an inelastic arterial bed, systolic and pulse pressures may be normal or even increased. )

The cardiac impulse is sustained and becomes displaced inferiorly and laterally . systolic thrill (It is palpated most readily in the second right intercostal space or suprasternal notch and is frequently transmitted along the carotid arteries. It thrill is specific, but not sensitive, for severe AS. )

Auscultation The ejection systolic murmur "diamond shaped, crescendo-decrescendo.Typically is late peaking and heard best at the base of the heart, with radiation to the carotids . Cessation of the murmur before A2 is helpful in differentiation from a pansystolic MR murmur.In patients with calcified aortic valves, the systolic murmur is loudest at the base of the heart, but high-frequency components may radiate to the apex (Gallavardin phenomenon), in which the murmur may be so prominent that it is mistaken for the murmur of MR. A louder and later peaking murmur indicates more severe stenosis.When the left ventricle fails and stroke volume falls, the systolic murmur of AS becomes softer; rarely, it disappears altogether. The slow rise in the arterial pulse is more difficult to recognize The intensity of the systolic murmur varies from beat to beat when the duration of diastolic filling varies, as in AF or following a premature contraction. This characteristic is helpful in differentiating AS from MR, in which the murmur is usually unaffected. Splitting of the second heart sound helpful in excluding the diagnosis of severe AS because normal splitting implies the AV leaflets are flexible enough to create an audible closing sound (A2). . A S4 heart sound is also often present due to the severe concentric left ventricular hypertrophy that develops in aortic stenosis. If a S3 heart sound is present, then significant systolic dysfunction has developed which is common in end stage aortic stenosis.

Diagnostic Evaluation Modalities Echocardiography (definition of valve anatomy, including the cause of AS and the severity of valve calcification, evaluation of LV hypertrophy and systolic function, mean transaortic pressure gradient with calculation of the ejection fraction, and for measurement of aortic root dimensions and detection of associated mitral valve disease.)Cardiac Catheterization and Angiography Computed Tomography Cardiac MR

Clinical Outcome 2 years in patients with heart failure .3 years in those with syncope5 years in those with angina Asymptomatic Symptomatic

The average rate of hemodynamic progression :annual decrease in aortic valve area of 0.12cm2/yearan increase in aortic jet velocity of 0.32m/sec/yearan increase in mean gradient of 7mmHg/year. Exercise test is helpful :Symptoms on treadmill exercise a decrease in blood pressure with exertion An elevated BNP level may be helpful when symptoms are equivocal or when stenosis severity is only moderate.

Management Symptomatic patients with severe AS are usually operative candidates because medical therapy has little to offer .Medical therapy may be necessary for patients considered to be inoperable , HF , HT, CAD.Diretics ,ACE inh. ,Statins,DC Cardiversion in AF

Surgical Treatment

Aortic Regurgitation

Causes and Pathology

Valvular Disease calcific AR infective endocarditis trauma congenitally bicuspid valve Rheumatic fever SLErheumatoid arthritisankylosing spondylitis Takayasu disease, Whipple disease,

Aortic Root Disease Marfan syndrome; aortic dilation related to bicuspid valvesaortic dissection, osteogenesis imperfecta, syphilitic aortitis, ankylosing spondylitis, the Beh?et syndrome,giant cell arteritis, systemic hypertension

Pathophysiology

Clinical Presentation Most of the patients remaining asymptomatic for a long period of time early in disease. exertional dyspneaAngina(It may occur in the absence of atherosclerotic coronary disease since the low diastolic pressures in severe aortic regurgitation compromise coronary filling and the LVH results in increased oxygen demand)Syncopeheart failure(Signs of left and right heart failure occur late in disease. Left heart failure results in symptoms related to the low cardiac output. The pressure increases in the left heart transmit to the lungs causing pulmonary edema and shortness of breath. )Other symptoms related to low cardiac output include fatigue, weakness and in extreme cases, cardiac cachexia can occur.

Physical Findings

Quincke's Pulse: Capillary pulsation visible on the fingernail beds or tipsMusset's Sign: Head bobbing with each heartbeatMllers Sign: Systolic pulsation of the uvulaCorrigans Pulse: Water-hammer pulse. Rapid distention and collapse of arteriel pulseHills Sign: Popliteal cuff pressure more than 60 mmHg above brachial cuff pressureDuroziezs Sign: To-and-fro murmur over the femoral artery with the artery compressedTraubes sign: Pistol-shot sounds. Prominent systolic and diastolic sounds over the femoral arteriesIncreased pulse pressure (SBP increases and DBP decreases.)

Shelly's sign: Pulsation of the cervix.Rosenbach's sign: Hepatic pulsations.Becker's sign: Visible pulsation of the retinal arterioles.Gerhardt's sign (aka Sailer's sign): Pulsation of the spleen in the presence of splenomegaly.Mayne's sign: A decrease in diastolic blood pressure of 15 mmHg when the arm is held above the head (very non-specific).Landolfi's sign: Systolic contraction and diastolic dilation of the pupil.

Diastolic Murmur In ARIn moderate AR, a relatively loud early desending diastolic murmur is heard.With more severe AR, the murmur becomes longer, and will usually decrease in intensity.The classic murmur caused by the regurgitant flow is best heard along the lower left sternal border. In some cases (Marfans Syndrome, VSD w/AR , aortic dissection or aneurysm) it is best heard at the right sternal border. A lower-pitched mid-diastolic murmur is heard over apex this indicates what is called an Austin Flint murmur which indicates severe AR. (The murmur is not the regurgitant flow over the aortic valve, but rather vibrations in a restricted Mitral Valve when the left atrium empties and is met with the opposite flow from the aortic valve.)In addition to the diastolic murmur(s), a systolic flow murmur like in aortic stenosis may be heard. This is not necessarily indicating a calcified valve, as the increased velocity resulting from ventricular overload will also cause flow vibrations)

Diagnostic Evaluation Modalities Echocardiography (bicuspid valve, thickening of the valve cusps, other congenital abnormalities, prolapse of the valve, a flail leaflet, or vegetation )Electrocardiography (left axis deviation and a pattern of LV diastolic volume overload, characterized by an increase in initial forces (prominent Q waves in leads I, aVL, and V3 through V6) and a relatively small wave in lead V1 )Radiography Cardiac Magnetic Resonance Imaging Angiography

electrocardiography

Chest x ray

echocardiography

Disease Course asymptomatic symptomatic

Management Medical Treatment :There is no specific therapy to prevent disease progression in chronic AR. Systemic arterial hypertension, should be treated because it increases the regurgitant flow; vasodilating agents such as ACE inhibitors or ARB are preferred, and beta-blocking agents should be used with great caution. Chronic medical therapy may be necessary for some patients who refuse surgery or are considered to be inoperable because of comorbid conditions. These patients should receive an aggressive heart failure regimen with ACE inhibitors (and perhaps other vasodilators), digoxin, diuretics, and salt restriction; beta blockers may also be beneficial.

Surgical Treatment

Acute Aortic Regurgitation Causes: infective endocarditis, aortic dissection, trauma The characteristic features of acute AR are tachycardia and an increase in LV diastolic pressures. The sudden increase in LV filling causes the LV diastolic pressure to rise rapidly above left atrial pressure during early diastole .Premature closure of the mitral valve, together with tachycardia that also shortens diastole, reduces the time interval during which the mitral valve is open. The tachycardia may compensate for the reduced forward stroke volume, and the LV and aortic systolic pressures may exhibit little change. Acute severe AR may cause profound hypotension and cardiogenic shock .Weakness, severe dyspnea, and profound hypotension secondary to the reduced stroke volume and elevated left atrial pressure .

Physical Examination tachycardia, severe peripheral vasoconstriction, and cyanosis, and sometimes pulmonary congestion and edema. S1 may be soft or absent because of premature closure of the mitral valve, and the sound of mitral valve closure in mid or late diastole is occasionally audible. Closure of the mitral valve may be incomplete, and diastolic MR may occur The early diastolic murmur of acute AR is lower pitched and shorter than that of chronic AR because as LV diastolic pressure rises, the (reverse) pressure gradient between the aorta and left ventricle is rapidly reduced.

Echocardiography:In acute AR the echocardiogram reveals a dense, diastolic Doppler signal with an end-diastolic velocity approaching zero and premature closure and delayed opening of the mitral valve. LV size and ejection fraction are normal. Electrocardiography: In acute AR, the ECG may or may not show LV hypertrophy, depending on the severity and duration of the regurgitation. However, nonspecific ST-segment and T wave changes are common.Radiography :In acute AR, there is often evidence of marked pulmonary venous hypertension and pulmonary edema.

Management Early death caused by LV failure is frequent in patients with acute severe AR despite intensive medical management, prompt surgical intervention is indicated. Even a normal ventricle cannot sustain the burden of acute, severe volume overload. While the patient is being prepared for surgery, treatment with an intravenous positive inotropic agent (dopamine or dobutamine) and/or a vasodilator (nitroprusside) is often necessary. In hemodynamically stable patients with acute AR secondary to active infective endocarditis, operation may be deferred to allow 5 to 7 days of intensive antibiotic therapy . However, AVR should be undertaken at the earliest sign of hemodynamic instability or if echocardiographic evidence of diastolic closure of the mitral valve develops.

MITRAL STENOSIS

MITRAL VALVE ANATOMY

Rheumatic FeverCongenital Mitral Stenosis

Etiology

Increased left atrial pressurePulmonary vasoconstrictionPulmonary HypertensionRight Ventricular FailureDecreased cardiac output

Pathophysiology

Pathophysiology

Right Heart Failure:Hepatic CongestionJVDTricuspid RegurgitationRA Enlargement Pulmonary HTNPulmonary CongestionLA EnlargementAtrial FibLA Thrombi LA Pressure RV Pressure OverloadRVHRV Failure

LV Filling

Symptoms

Fatigue PalpitationsCough Chest painSOBLeft sided failureOrthopneaPNDExercise dyspneaPalpitationHoarseness (Ortners syndrome

AfibSystemic embolism"Blue toe syndrome, strokePulmonary infectionHemoptysisdue to sudden rupture of a bronchial vein. This phenomenon is termed "pulmonary apoplexy". Right sided failureHepatic CongestionEdema

Exertion Fever Anemia Pregnancy Atrial Fibrillationhypertiroid

Precipitating Factors

Recognizing Mitral StenosisPalpation:Small volume pulseTapping apex-palpable S1+/- palpable opening snap (OS)RV liftPalpable S2ECG: LAE, AFIB, RVH, RAD

Auscultation:Loud S1- as loud as S2 in aortic areaA2 to OS interval inversely proportional to severityDiastolic rumble: length proportional to severityIn severe MS with low flow- S1, OS & rumble may be inaudible

Mitral Stenosis: Physical ExamFirst heart sound (S1) is accentuated and snappingOpening snap (OS) after aortic valve closureLow pitch diastolic rumble at the apex. The murmur ofmitral stenosis is low frequency and is referred to as a "rumble". Pre-systolic accentuation (esp. if in sinus rhythm)

S1 S2 OS S1

Jugular venous pulsations may reveal a prominent A wave due to vigorous atrial contraction of a prominent V wave due to tricuspid regurgitation that develops from pulmonary hypertension. The presence of "mitral facies" refers to a pinkish-purple discoloration of the cheeks produced by a chronic low cardiac output state combined with systemic vasoconstriction. Palpable S1 over the apex is pathognomonic for mitral stenosis

Common Murmurs and TimingSystolic MurmursAortic stenosisMitral insufficiencyMitral valve prolapseTricuspid insufficiency Diastolic MurmursAortic insufficiencyMitral stenosis S1 S2 os S1

Chest XRay Double density of left atrial enlargement Right ventricular enlargement Posterior displacement of esophagus Mitral valve calcification Kerley B Lines

Radiology

Mitral Stenosis - upper lobe blood diversionTrivial enlargement of the transverse diameter of the heart. Left atrium causes double outline (opposite right arrow) and is somewhat dilated. Left atrial appendage is dilated, causing a prominence of the left border (opposit left arrow). Upper lobe vessels larger than lower lobe vessels, that is, upper lobe blood diversion. An arrow points to a dilated upper lobe vein.

Mitral Stenosis - septal line shadows. Kerley "B" Horizontal short line shadows, septal (Kerley "B") lines above the costo-phrenic recesses, indicating interstitial oedema of the septa, often with haemosiderin in the adjacent alveoli.

Mitral Stenosis - hilar oedema Hilar vessels indistinct, peri-hilar haze. Also upper lobe blood diversion and septal line shadows. Arrow points to a Kerley "A" line, due either to septal oedema or oedema around an intercommunicating lymphatic during its course from a perivenous to a pericardial position or vice versa.

echocardiographyEchocardiogram Mitral valve leaflet changes Inadequate separation of valve leaflets Valve leaflet calcification and thickening Doppler estimates transvalvular gradient

Accentuated precordial thrust of right ventricle Elevated neck veins AscitesEdema Signs: Later findings of right ventricular failure

Hemoptysis Embolism Pulmonary infection EndocarditisAtrial fibrillation

Complications

Slow, progressive, life-long course Latent period of 20 to 40 years after Rheumatic Fever Rapid acceleration of symptoms in later life

Prognosis

Rheumatic Fever prophylaxis until age 40 years Benzathine Penicillin G 1.2 MU IM monthly OR Penicillin VK 125-250 mg PO bid Treat complications and associated conditions Atrial Fibrillation Congestive Heart Failure Anticoagulation for history of emboli Beta blocker. Digitalis.diretics

Management

Open Mitral valvotomyMitral Valve Replacement

Percutaneous balloon valvuloplasty

Management

MITRAL REGURGITATION

MITRAL VALVE ANATOMY

Rheumatic Heart Disease Mitral Valve Prolapse Ischemic Heart Disease and papillary muscle dysfunction Left Ventricular dilatation Mitral annular calcification Hypertrophic Cardiomyopathy Infective endocarditis Congenital mitral regurgitationEtiology

Early or compensated mitral regurgitation Volume overload Left Ventricular Hypertrophy Left atrial enlargement Late or decompensated mitral regurgitation Left Ventricular Failure Decreased ejection fraction Pulmonary congestionPathophysiology

Pathophysiology of mitral regurgitationIn the normal heart, left ventricular (LV) contraction during systole forces blood exclusively through the aortic valve into the aorta; the closed mitral valve prevents regurgitation into the left atrium (LA). In mitral regurgitation (MR), a portion of the LV output is forced retrograde into the LA, so that forward cardiac output into the aorta is reduced. In acute MR, the LA is of normal size and is noncompliant, such that the LA pressure rises markedly and pulmonary edema may result. In chronic MR, the LA has enlarged and is more compliant, such that LA pressure is less elevated and pulmonary congestive symptoms are less common if LV contractile function is intact. There is LV enlargement and eccentric hypertrophy due to the chronic increased volume load.

Pathophysiology

The severity of MR and the ratio of forward cardiac flow (cardiac output) to backward flow are determined by several, interacting factors: 1) the size of the mitral orifice during regurgitation 2) the systemic vascular resistance opposing forward flow from the ventricle 3) the compliance of the left atrium 4) the systolic pressure gradient between the LV and the LA 5) the duration of regurgitation during systole (not all regurgitation is holo-systolic)

DyspneaFatigue Weakness Cough Symptoms

Holosystolic Murmur at Apex Harsh, medium pitched pansystolic murmur Radiation Axilla(left) Upper sternal borders Subscapular region Soft or diminished First Heart Sound (S1) P2 heart sound augmented S2 Heart Sound with wide split S3 Gallop rhythm (indicative of severe disease) Accentuated and displaced precordial Apical Thrust Systolic thrill Physical findings

MURMUR

Electrocardiogram Left Ventricular Hypertrophy Left Axis Deviation Left atrial enlargement Laboratuary findings

CHEST X-RAY Enlarged left atrium Dilated left ventricle

echocardiography Enlarged left atrium Hyperdynamic left ventricle Doppler assess severity

Annual or semi-annual echocardiogram Assess ejection fraction Assess end-systolic dimension Management Anticoagulation in Atrial FibrillationTreat Congestive Heart FailureDiuretic Digoxin Afterload reduction ACE Inhibitor Hydralazine Nitroprusside (especially acute MR)Monitoring

Mitral Valve repair or replacement Repair before Heart Failure develops Keep ejection fraction >60% Keep end-systolic dimension

Left ventricular outflow obstruction most commonly occurs at the aortic valve, however it can occur above the aortic valve (supravalvular) or below the aortic valve as in hypertrophic obstructive cardiomyopathy (HOCM). Severe uncontrolled systemic hypertension (increased afterload) may have similar hemodynamic effects on the heart when compared to aortic stenosis, since both disease states result in a significantly increased afterload. However cardiac reserve is severely limited in aortic stenosis when compared to severe hypertension due to the reduced and fixed aortic valve area causing the symptoms of aortic stenosis to be predominantly exertional.*The most common cause of aortic stenosis in a person over the age of 70 results from calcification of a normal trileaflet aortic valve. This process is sometimes referred to as "senile degeneration". Known risk factors for developing degenerative calcific aortic stenosis include hypercholesterolemia and diabetes. Statin drugs were thought to reduce the progression of degenerative calcific aortic stenosis, however this remains controversial. The exact cause of the degeneration is unknown, however it is speculated that high pressures and turbulence over long periods of time creates an inflammatory state resulting in infiltration of macrophages and T lymphocytes with resultant calcification. The most common cause of aortic stenosis in a person under the age of 70 results from a congenital bicuspid aortic valve. Approximately 2% of the population is born with a bicuspid aortic valve and about half of these individuals develop at least mild aortic stenosis by the age of 50. Rheumatic valvular disease is responsible for aortic stenosis on occasion. In this setting, there is almost always concurrent disease of the mitral valve present and frequently at least some aortic regurgitation accompanies aortic stenosis when rheumatic. While the incidence of rheumatic aortic stenosis is quite low in the United States, the worldwide incidence is much higher. Congenital aortic stenosis results from fusion of the aortic valve leaflets at birth. Infants with congenital AS exhibit significantly more left ventricular hypertrophy than do adults, yet they rarely develop symptoms of heart failure. Sudden death without prior symptoms occurs in about 15% of cases. Balloon valvotomy is the treatment of choice for congenital aortic stenosis. Other rare causes of aortic stenosis include inflammatory diseases (i.e. SLE or RA), severe familial hypercholesterolemia, ochronosis, Paget's disease of the bone, and Fabry's disease.

**The classic triad of symptoms of aortic stenosis occur on exertion and include dyspnea, syncope, and angina. The development of aortic stenosis takes many years and is initially asymptomatic. Dyspnea is the first symptom of aortic stenosis in about 50% of the cases while syncope and angina account for 35% and 15% of initial symptoms respectively. The clinical significance of a patient with aortic stenosis exhibiting symptoms cannot be underemphasized since the onset of symptoms is accompanied by a dramatic increase in mortality. According to one large series, if aortic valve replacement is not performed, patients presenting with dyspnea have a mean life expectancy of 2 years, those with syncope about 3 years, and those presenting with angina have an average of 5 years.

Chronic pressure overload typically results in concentric LV hypertrophy, with increased wall thickness and a normal chamber size. The increased wall thickness allows normalization of wall stress (afterload) so that LV contractile function is maintained. However, the increased myocardial cell mass and increased interstitial fibrosis result in diastolic dysfunction, which may persist even after relief of AS. Gender differences in the LV response to AS have been reported, with women more frequently exhibiting normal LV performance and a smaller, thicker walled, concentrically hypertrophied left ventricle with diastolic dysfunction (see later) and normal or even subnormal systolic wall stress. Men more frequently have eccentric LV hypertrophy, excessive systolic wall stress, systolic dysfunction, and chamber dilation.The LV changes caused by chronic pressure overload are reflected in the LV and left atrial pressure waveforms and Doppler velocity curves. As contraction of the left ventricle becomes progressively more isometric, the LV pressure pulse exhibits a rounded, rather than flattened, summit and the Doppler velocity curve exhibits a progressively later systolic peak. The elevated LV end-diastolic pressure and the corresponding Doppler changes in LV filling, which are characteristic of severe AS, reflect delayed relaxation and eventually decreased compliance of the hypertrophied LV wall. In patients with severe AS, large a waves usually appear in the left atrial pressure pulse and Doppler LV filling curve because of the combination of enhanced contraction of a hypertrophied left atrium and diminished LV compliance. Atrial contraction plays a particularly important role in filling of the left ventricle in AS. It raises LV end-diastolic pressure without causing a concomitant elevation of mean left atrial pressure. This booster pump function of the left atrium prevents the pulmonary venous and capillary pressures from rising to levels that would produce pulmonary congestion, whereas at the same time maintaining LV end-diastolic pressure at the elevated level necessary for effective contraction of the hypertrophied left ventricle. These changes in diastolic function are reflected in the Doppler parameter of LV filling and noninvasive measures of diastolic function, such as strain and strain rate .Loss of appropriately timed, vigorous atrial contraction, as occurs in atrial fibrillation (AF) or atrioventricular dissociation, may result in rapid clinical deterioration in patients with severe AS.Systemic vascular resistance also contributes to total LV afterload in adults with AS. Concurrent hypertension increases total LV load and may affect the evaluation of AS severity.[34] Mild pulmonary hypertension is present is about one third of adults with AS because of the chronic elevation of LV end-diastolic pressure; more severe pulmonary hypertension is seen in about 15% of AS patients.Exercise physiology is abnormal in adults with moderate to severe AS, and even asymptomatic patients have a reduced exercise tolerance. Although cardiac output at rest is within normal limits, the normal increase in cardiac output with exercise is blunted and is mediated primarily by increased heart rate, with little change in stroke volume. Even though stroke volume is unchanged, transvalvular flow rate increases because of the shortened systolic ejection period so that aortic jet velocity and transvalvular gradient increase proportionally. Prior to symptom onset, valve area increases slightly with exercise (by 0.2cm2 on average) but as AS becomes more severe and symptoms are imminent, valve area becomes fixed, resulting in an even greater rise in jet velocity and pressure gradient with exercise. At this point, there is an abnormal blood pressure response to exercise (rise in systolic blood pressure < 10mmHg), signifying severe valve obstruction.Myocardial Function in Aortic Stenosis :In patients with AS, coronary blood flow at rest is elevated in absolute terms but is normal when corrections are made for myocardial mass. Reduced coronary blood flow reserve may produce inadequate myocardial oxygenation in patients with severe AS, even in the absence of coronary artery disease. The hypertrophied LV muscle mass, increased systolic pressure, and prolongation of ejection all elevate myocardial oxygen consumption. The abnormally heightened pressure compressing the coronary arteries may exceed the coronary perfusion pressure and the shortening of diastole interferes with coronary blood flow, thus leading to an imbalance between myocardial oxygen supply and demand . Myocardial perfusion is also impaired by the relative decrease in myocardial capillary density as myocardial mass increases and by the elevation of LV end-diastolic pressure, which lowers the aortic-LV pressure gradient in diastole (i.e., the coronary perfusion pressure gradient). This underperfusion may be responsible for the development of subendocardial ischemia, especially when oxygen demand is increased or the diastolic filling period is reduced (e.g., tachycardia, anemia, infection, pregnancy). *Effort syncope occurs in aortic stenosis due to a sudden decrease in cerebral perfusion upon exertion. During exercise, the total peripheral resistance (TPR) decreases significantly since blood is being shunted toward working muscles. In the presence of significant aortic stenosis, the cardiac output cannot increase enough to accommodate this decreased TPR and cerebral perfusion is compromised resulting in syncope. This idea can be further reinforced by recalling the following equation: MAP = CO X TPR MAP = mean arterial pressure CO = cardiac output So if the cardiac output is not able to increase due to severe aortic stenosis and the TPR decreases during exertion, the MAP will subsequently be reduced leading to decreased cerebral perfusion and syncope. It is important to note that another cause of syncope in patients with aortic stenosis is arrhythmias, especially atrial fibrillation and AV nodal blocks, as will be described later. Dyspnea on exertion is due to heart failure. Both systolic and diastolic dysfunction typically contributes to heart failure in patients with aortic stenosis. Other classic symptoms of heart failure are also common and include orthopnea, PND, and signs of right sided heart failure (i.e. peripheral edema). Other rare initial symptoms in a patient with aortic stenosis include embolic phenomenon from calcified aortic valve plaques or massive GI bleeding due to angiodysplasia (Heyde's syndrome). Heyde's syndrome is thought to be due to disruption of the pentamer structure of the von Willebrand factor as it traverses the severely stenotic aortic valve leading to an increase tendency to bleed from angiodysplasias.

Symptoms typically occur at age 50 to 70 years with bicuspid aortic valve stenosis and in those older than 70 years with calcific stenosis of a trileaflet valve, although even in this age group about 40% of AS patients have a congenital bicuspid valve .Angina occurs in approximately two thirds of patients with severe AS, about 50% of whom have associated significant coronary artery obstruction. It usually resembles the angina observed in patients with coronary artery disease (see Chap. 53) in that it is commonly precipitated by exertion and relieved by rest. In patients without coronary artery disease, angina results from the combination of the increased oxygen needs of hypertrophied myocardium and reduction of oxygen delivery secondary to the excessive compression of coronary vessels. In patients with coronary artery disease, angina is caused by a combination of epicardial coronary artery obstruction and the oxygen imbalance characteristic of AS. Very rarely, angina results from calcium emboli to the coronary vascular bed .Syncope is most commonly caused by the reduced cerebral perfusion that occurs during exertion when arterial pressure declines consequent to systemic vasodilation in the presence of a fixed cardiac output. Syncope has also been attributed to malfunction of the baroreceptor mechanism in severe AS (see Chap. 94), as well as to a vasodepressor response to a greatly elevated LV systolic pressure during exercise. Premonitory symptoms of syncope are common. Exertional hypotension may also be manifested as graying out spells or dizziness on effort. Syncope at rest may be caused by transient AF with loss of the atrial contribution to LV filling, which causes a precipitous decline in cardiac output, or to transient atrioventricular block caused by extension of the calcification of the valve into the conduction system. Infective endocarditis is a greater risk in younger patients with milder valvular deformity than in older patients with rocklike calcific aortic deformities. Cerebral emboli resulting in stroke or transient ischemic attack may be caused by microthrombi on thickened bicuspid valves. Calcific AS may cause embolization of calcium to various organs, including the heart, kidneys, and brain. Syncope is most commonly caused by the reduced cerebral perfusion that occurs during exertion when arterial pressure declines consequent to systemic vasodilation in the presence of a fixed cardiac output. Syncope has also been attributed to malfunction of the baroreceptor mechanism in severe AS (see Chap. 94), as well as to a vasodepressor response to a greatly elevated LV systolic pressure during exercise. Premonitory symptoms of syncope are common. Exertional hypotension may also be manifested as graying out spells or dizziness on effort. Syncope at rest may be caused by transient AF with loss of the atrial contribution to LV filling, which causes a precipitous decline in cardiac output, or to transient atrioventricular block caused by extension of the calcification of the valve into the conduction system. *The cardiac impulse is sustained and becomes displaced inferiorly and laterally with LV failure. Presystolic distention of the left ventricle (i.e., a prominent precordial a wave) is often visible and palpable. A hyperdynamic left ventricle suggests concomitant AR and/or MR. A systolic thrill is usually best appreciated when the patient leans forward during full expiration. It is palpated most readily in the second right intercostal space or suprasternal notch and is frequently transmitted along the carotid arteries. A systolic thrill is specific, but not sensitive, for severe AS. *Auscultation of the heart in patients with aortic stenosis can be very helpful in both the diagnosis and in determining the severity of disease. The typical murmur of aortic stenosis is a high-pitched, "diamond shaped" crescendo-decrescendo, midsystolic ejection murmur heard best at the right upper sternal border radiating to the neck and carotid arteries (see figure below). In mild aortic stenosis, the murmur peaks in early systole, however as the disease progresses the peak moves to later in systole since longer time is required to complete LV systole and aortic valve closure is delayed. The intensity of the murmur typically increases as disease progresses, however when heart failure develops and cardiac output declines, the murmur becomes softer. Thus the intensity of the murmur is not a good indicator of disease severity Auscultation at the cardiac apex may reveal a murmur that may sound midsystolic or holosystolic and may mimic the murmur of mitral regurgitation. However this is commonly the result of radiation of the murmur of aortic stenosis to the apex rather than coexistent mitral regurgitation. This finding is referred to as "Gallavardin dissociation". To determine if the apical murmur is indeed due to mitral regurgitation or radiation of the murmur of aortic stenosis, dynamic auscultation can be undertaken (see section on dynamic auscultation). The murmur of hypertrophic cardiomyopathy can also at times mimic the murmur of aortic stenosis. The Valsalva maneuver decreases the murmur of aortic stenosis while it increases the murmur of hypertrophic cardiomyopathy. The S2 heart sound is often paradoxically split in patients with aortic stenosis due to the significantly delayed closure of the aortic valve resulting from the increased time needed to complete LV systole.As disease progresses and the aortic valve leaflets lose their mobility, the intensity of S2 decreases. When the S2 sound is no longer audible, it can be concluded that the aortic stenosis is relatively severe. A S4 heart sound is also often present due to the severe concentric left ventricular hypertrophy that develops in aortic stenosis. If a S3 heart sound is present, then significant systolic dysfunction has developed which is common in end stage aortic stenosis. Perhaps the best bedside method to estimate the severity of aortic stenosis is derived from evaluation of the carotid arteries. The phenomenon known as "pulsus parvus et tardus" refers to a weak (parvus) and delayed (tardus) carotid upstroke. To asses for "parvus", it is often helpful to palpate ones own carotid artery while concurrently palpating the patient's carotid artery. It is important to note that in some elderly individuals the carotids may be stiff due to calcification, which may falsely normalize the carotid upstroke. To assess for "tardus", auscultate the patient's S2 heart sound while palpating their carotid upstroke. The S2 and carotid upstroke should occur almost simultaneously. If the carotid upstroke comes significantly after the S2 heart sound, "tardus" is present indicating severe aortic stenosis. Other physical exam findings in patients with aortic stenosis include those of both right and left heart failure.

The ejection systolic murmur of AS typically is late peaking and heard best at the base of the heart, with radiation to the carotids (see Fig. 66-4). Cessation of the murmur before A2 is helpful in differentiation from a pansystolic mitral murmur. In patients with calcified aortic valves, the systolic murmur is loudest at the base of the heart, but high-frequency components may radiate to the apex (the so-called Gallavardin phenomenon), in which the murmur may be so prominent that it is mistaken for the murmur of MR. In general, a louder and later peaking murmur indicates more severe stenosis. However, although a systolic murmur of grade 3 intensity or greater is relatively specific for severe AS, this finding is insensitive and many patients with severe AS have only a grade 2 murmur. High-pitched decrescendo diastolic murmurs secondary to AR are common in many patients with dominant AS.Splitting of the second heart sound is helpful in excluding the diagnosis of severe AS because normal splitting implies the aortic valve leaflets are flexible enough to create an audible closing sound (A2). With severe AS, the second heart sound (S2) may be single because calcification and immobility of the aortic valve make A2 inaudible, closure of the pulmonic valve (P2) is buried in the prolonged aortic ejection murmur, or prolongation of LV systole makes A2 coincide with P2. Paradoxical splitting of S2, which suggests associated left bundle branch block or LV dysfunction, may also occur. Thus, in older adults, normal splitting of S2 indicates a low likelihood of severe AS. The first heart sound (S1) is normal or soft and a fourth heart sound (S4) is prominent, presumably because atrial contraction is vigorous and the mitral valve is partially closed during presystole.The intensity of the systolic murmur varies from beat to beat when the duration of diastolic filling varies, as in AF or following a premature contraction. This characteristic is helpful in differentiating AS from MR, in which the murmur is usually unaffected. The murmur of valvular AS is augmented by squatting, which increases stroke volume. It is reduced in intensity during the strain of the Valsalva maneuver and when standing, which reduce transvalvular flow *Symptomatic patients with severe AS are usually operative candidates because medical therapy has little to offer. However, medical therapy may be necessary for patients considered to be inoperable, usually because of comorbid conditions that preclude surgery. Some of these patients may be candidates for transcatheter valve implantation, but others will not be candidates for or will decline this procedure. Although diuretics are beneficial when there is abnormal accumulation of fluid, they must be used with caution because hypovolemia may reduce the elevated LV end-diastolic pressure, lower cardiac output, and produce orthostatic hypotension. ACE inhibitors should be used with caution but are beneficial in treating patients with symptomatic LV systolic dysfunction who are not candidates for surgery. They should be initiated at low doses and increased slowly to target doses, avoiding hypotension. Beta-adrenergic blockers can depress myocardial function and induce LV failure, and should be avoided in patients with AS.AF or atrial flutter occurs in less than 10% of patients with severe AS, perhaps because of the late occurrence of left atrial enlargement in this condition. When such an arrhythmia is observed in a patient with AS, the possibility of associated mitral valvular disease should be considered. When AF occurs, the rapid ventricular rate may cause angina pectoris. The loss of the atrial contribution to ventricular filling and a sudden fall in cardiac output may cause serious hypotension. Therefore, AF should be treated promptly, usually with cardioversion. New-onset AF in a previously asymptomatic patient with severe AS may be a marker of impending symptom onset.Management of concurrent cardiac conditions, such as hypertension and coronary disease, is complicated in patients with asymptomatic AS by the concern that the vasodilatory effects of medications may not be offset by a compensatory increase in cardiac output. Despite this concern, AS patients should receive appropriate treatment for concurrent disease, although medications should be started at low doses and slowly titrated upward, with close monitoring of blood pressure and symptoms. Adults with asymptomatic severe AS can undergo noncardiac surgery and pregnancy, with careful hemodynamic monitoring and optimization of loading conditions. However, when stenosis is very severe, elective AVR prior to noncardiac surgery or a planned pregnancy may be considered.*In contrast to MR, in which a fraction of the LV stroke volume is ejected into the low-pressure left atrium, in AR the entire LV stroke volume is ejected into a high-pressure chamber (i.e., the aorta), although the low aortic diastolic pressure does facilitate ventricular emptying during early systole (Fig. 66-9). In MR, especially acute MR, the reduction of wall tension (i.e., reduced afterload) allows more complete systolic emptying; in AR the increase in LV end-diastolic volume (i.e., increased preload) provides hemodynamic compensation Pathophysiology of aortic regurgitation. Aortic regurgitation results in an increased LV volume, increased stroke volume, increased aortic (Ao) systolic pressure, and decreased effective stroke volume. Increased LV volume results in an increased LV mass, which may lead to LV dysfunction and failure. Increased LV stroke volume increases systolic pressure and prolongation of LV ejection time (LVET). Increased LV systolic pressure results in a decrease in diastolic time. Decreased diastolic time (myocardial perfusion time), diastolic aortic pressure, and effective stroke volume reduce myocardial O2 supply. Increased myocardial O2 consumption and decreased myocardial O2 supply produce myocardial ischemia, which further deteriorates LV function .Severe AR may occur with a normal effective forward stroke volume and a normal ejection fraction ([forward plus regurgitant stroke volume]/[end-diastolic volume]), together with an elevated LV end-diastolic volume, pressure, and stress (Fig. 66-10).[91] In accord with Laplace's law, which indicates that wall tension is related to the product of the intraventricular pressure and radius divided by wall thickness, LV dilation also increases the LV systolic tension required to develop any level of systolic pressure. Thus, in AR, there is an increase in preload and afterload. LV systolic function is maintained through the combination of chamber dilation and hypertrophy. This leads to eccentric hypertrophy, with replication of sarcomeres in series and elongation of myocytes and myocardial fibers. In compensated AR, there is sufficient wall thickening so that the ratio of ventricular wall thickness to cavity radius remains normal. This maintains or returns end-diastolic wall stress to normal levels. AR contrasts with AS, in which there is pressure overload (concentric) hypertrophy with replication of sarcomeres, largely in parallel, and an increased ratio of wall thickness to radius but, like AS, there is an increase in interstitial connective tissue. In AR, LV mass is usually greatly increased, often to levels even higher than in isolated AS. As AR persists and increases in severity over time, wall thickening fails to keep pace with the hemodynamic load and end-systolic wall stress rises. At this point, the afterload mismatch results in a decline in systolic function, and the ejection fraction fallsPatients with severe chronic AR have the largest end-diastolic volumes of those with any form of heart disease, resulting in so-called cor bovinum. However, end-diastolic pressure is not uniformly elevated (i.e., LV compliance is often increased; see Fig. 66-10). In more severe cases of AR, the regurgitant flow may exceed 20 liters/min, so the total LV output at rest approaches 25 liters/min, a level that can be achieved acutely only by a trained endurance runner during maximal exercise. Thus, the adaptive response to gradually increasing, chronic AR permits the ventricle to function as an effective high-compliance pump, handling a large stroke volume, often with little increase in filling pressure. During exercise, peripheral vascular resistance declines and, with an increase in heart rate, diastole shortens and the regurgitation per beat decreases, facilitating an increment in effective (forward) cardiac output without substantial increases in end-diastolic volume and pressure. The ejection fraction and related ejection phase indices are often within normal limits, both at rest and during exercise, even though myocardial function, as reflected in the slope of the end-systolic pressure-volume relationship, is depressed.As the left ventricle decompensates, interstitial fibrosis increases, compliance declines, and LV end-diastolic pressure and volume rise (see Fig. 66-10). In advanced stages of decompensation, left atrial, pulmonary artery wedge, pulmonary arterial, right ventricular (RV), and right atrial pressures rise and the effective (forward) cardiac output falls, at first during exercise and then at rest. The normal decline in end-systolic volume or the rise in ejection fraction fails to occur during exercise. Symptoms of heart failure develop, particularly those secondary to pulmonary congestion.When acute AR is induced experimentally, myocardial oxygen requirements rise substantially, secondary to an increase in wall tension. In patients with chronic severe AR, total myocardial oxygen requirements are also augmented by the increase in LV mass. Because the major portion of coronary blood flow occurs during diastole, when arterial pressure is lower than normal in AR, coronary perfusion pressure is reduced. Studies in experimentally induced AR have shown a reduction in coronary flow reserve, with a change in forward coronary flow from diastole to systole. The resulta combination of increased oxygen demands and reduced supplysets the stage for the development of myocardial ischemia, especially during exercise. Thus, patients with severe AR exhibit a reduction of coronary reserve, which may be responsible for myocardial ischemia and which may in turn play a role in the deterioration of LV function.The symptoms of aortic valve regurgitation are those predominately of congestive heart failure.As chronic aortic regurgitation develops slowly over time, the left ventricle can easily compensate slowly as described previously. This results in patients remaining asymptomatic for a long period of time early in disease. The first symptoms experienced may result from the large stroke volumes and forceful LV contractions causing the patient to experience palpitations. Angina may occur in the absence of atherosclerotic coronary disease since the low diastolic pressures in severe aortic regurgitation compromise coronary filling and the LVH results in increased oxygen demand.Signs of left and right heart failure occur late in disease.Left heart failure results in symptoms related to the low cardiac output. The pressure increases in the left heart transmit to the lungs causing pulmonary edema and shortness of breath. With physical activity the heart demands increased cardiac output which is not able to be met in states of heart failure and thus left heart pressures increase significantly causing this transient pulmonary edema.As those increased pressures from the left heart affect the right ventricle, right heart failure can ensue. The most common cause of right heart failure is left heart failure.Right heart failure symptoms include lower extremity dependant edema. When the legs are elevated at night, the fluid redistributes centrally causing pulmonary edema resulting in orthopnea (dyspnea while laying flat) or paroxysmal nocturnal dyspnea (PND). Hepatic congestion can occur causing right upper quadrant abdominal pain.Other symptoms related to low cardiac output include fatigue, weakness and in extreme cases, cardiac cachexia can occur.Almost all patients with significant acute aortic regurgitation are symptomatic, unlike chronic aortic regurgitation. Symptoms of acute left heart failure occur and include severe dyspnea even at rest, orthopnea, and PND. Hypotension and shock may occur.

*In chronic aortic regurgitation, visible cardiac and arterial pulsations are common due to the large stroke volume. The carotid pulse can commonly be seen. The PMI is displaced laterally and caudally due to the LV dilation and hypertrophy that occurs. On auscultation, the typical murmur of aortic regurgitation is a soft, high-pitched, early diastolic decrescendo murmur heard best at the 3rd intercostal space on the left (Erb's point) on end expiration with the patient sitting up and leaning forward..This murmur is often difficult to distinguish from the Graham-Steele murmur of pulmonic insufficiency. If aortic root disease is the cause of the aortic regurgitation, the murmur will be heard best at the right upper sternal border and not at Erb's point. As aortic regurgitation worsens, the murmur becomes shorter in duration due to less time needed for LV and aortic pressure equalization.In addition to the above murmur, a systolic ejection murmur may be present at the right upper sternal border simply due to the large stroke volume passing through the aortic valve with each LV systolic contraction. An early diastolic rumble may also be heard at the apex due to the regurgitant jet striking the anterior leaflet of the mitral valve causing it to vibrate. This murmur is termed the Austin-Flint murmur.A widened pulse pressure is often present due to the high flow state as previously described. When severe heart failure develops, the pulse pressure will decrease and the below listed peripheral signs of aortic regurgitation are lessened. A fourth heart sound develops when LVH becomes severe and limits diastolic filling. A third heart sound is often present due to the increased early diastolic filling into a compliant, dilated LV.

**Because AR has complex effects on preload and afterload, the selection of appropriate indices of ventricular contractility to identify patients for operation is challenging. The relationship between end-systolic wall stress and ejection fraction or percentage fractional shortening is a useful measurement,[35] as are more load-independent measures of LV contractility. However, in the absence of such complex measurements, serial changes in ventricular end-diastolic and end-systolic volumes or dimensions can be used to detect the relative deterioration of ventricular function.[90] Although LV end-diastolic volume and ejection phase indices (e.g., ejection fraction, ventricular fraction shortening) are strongly influenced by loading conditions, they are nonetheless useful empirical predictors of postoperative function.Asymptomatic patients with severe AR but normal LV function have an excellent prognosis and do not warrant prophylactic operation (see Table 66-5). On average, less than 6% of patients/year require operation because of the development of symptoms or of LV dysfunction (see Fig. 66-13), although the rate of symptom development is higher in patients older than 60 years.[94] The LV end-systolic dimension determined by echocardiography is valuable in predicting outcome in asymptomatic patients. Patients with severe AR and an end-systolic diameter less than 40mm almost invariably remain stable and can be followed without immediate surgery. However, patients with an end-systolic diameter more than 50mm have a 19% likelihood/year of developing symptoms of LV dysfunction, and those with an end-systolic diameter more than 55mm have an increased risk of irreversible LV dysfunction if they are not operated on. Postoperative function and survival in this latter group is determined by the severity of symptoms, severity of LV dysfunction, and duration of LV dysfunction.[83,91] Indexed end-systolic dimension or volume (ESVI) may be a more robust indicator for timing of surgical intervention.[93,94] Patients with an ESVI 45mL/m2 are at higher risk of adverse outcomes.[94] Further data on the use of ESVI is needed before this approach becomes standard. In summary, the following considerations apply to the selection of patients with chronic AR for surgical treatment.[1] Operation should be deferred in asymptomatic patients with normal and stable LV function and should be recommended for symptomatic patients (see Fig 66-15). In asymptomatic patients with LV dysfunction, a decision should be based not on a single abnormal measurement but rather on several observations of depressed performance and impaired exercise tolerance, carried out at intervals of 2 to 4 months. If evidence of LV dysfunction is borderline or inconsistent, continued close follow-up is indicated. If abnormalities are progressive and consistent (i.e., LV ejection fraction 50%, LV end-systolic diameter rises to >55mm, or LV end-diastolic dimension rises to >75mm), operation should be strongly considered, even in asymptomatic patients. It is also reasonable to consider AVR at lower levels of LV dilation (end-systolic dimension >50mm; end-diastolic dimension >70mm) in patients with progressive LV dilation on serial imaging studies. Symptomatic patients with severe AR who have normal, mildly depressed, or moderately depressed LV function should be operated on. Patients with severely impaired LV function (ejection fraction < 25%) are at high surgical risk and have a guarded prognosis, even after successful AVR. However, their outlook is also extremely poor when they receive medical therapy alone, and their management should be considered on an individual basis. The indications for surgery for patients with severe AR secondary to aortic root disease are similar to those for patients with primary valvular disease. However, progressive expansion of the aortic root and/or a diameter more than 50mm by echocardiography with any degree of regurgitation in patients with a bicuspid valve (or other connective tissue disorder) or with a diameter more than 55mm in other patients is also an indication for aortic root replacement surgery *Mitral stenosis is often asymptomatic early in disease until the mitral valve area decreases enough to cause a large increase in left atrial pressure. The first symptoms of MS occur on exertion as explained above. This occurs since the mitral valve area is fixed and the cardiac output is unable to increase enough above resting (a low cardiac reserve is present), and high pressures are transmitted to the pulmonary vasculature since left atrial pressures increase exponentially on exertion. This transmission of pressures results in exertional dyspnea. Fatigue and inability to exercise are also common complaints. Signs of left heart failure such as paroxysmal nocturnal dyspnea and orthopnea can occur. Symptoms of heart failure with concomitant mitral stenosis also occur in disease states that require an increased cardiac output for the same reason such as pregnancy, anemia, sepsis and thyrotoxicosis.Most patients with moderate to severe mitral stenosis will have some degree left atrial enlargement (LAE) due to the chronic increased LA pressures. This predisposes them to atrial fibrillation. Since people with mitral stenosis rely on atrial contraction for about 20% of their cardiac output and since tachycardia decreases diastolic filling time, the onset of atrial fibrillation with a rapid ventricular rate and loss of atrial contraction results in significant symptoms of low cardiac output and heart failure. These include fatigue, dyspnea, lightheadedness, and even syncope.In the absence of atrial fibrillation, patients with mitral stenosis still have an increased risk of thrombus formation in their left atrial due to stagnation of blood. This may lead to embolic events including stroke, acute myocardial infarction, acute mesenteric ischemia, or "Blue toe syndrome".Hemoptysis may occur due to sudden rupture of a bronchial vein. This phenomenon is termed "pulmonary apoplexy". Ortner syndrome may occur when a massively enlarged left atrium compresses the left recurrent laryngeal nerve leading to a hoarse voice. Chest pain from right sided heart strain may occur due to severe venous pulmonary hypertension. Other signs of right heart failure such as right upper quadrant pain (due to hepatic congestion) and peripheral edema may occur

***Inspection of the jugular venous pulsations may reveal a prominent A wave due to vigorous atrial contraction of a prominent V wave due to tricuspid regurgitation that develops from pulmonary hypertension. The presence of "mitral facies" refers to a pinkish-purple discoloration of the cheeks produced by a chronic low cardiac output state combined with systemic vasoconstriction. This sign is rare and non-specific. Palpation may reveal a palpable S1 over the apex. This finding is pathognomonic for mitral stenosis. A diastolic thrill may rarely be appreciated at the apex with the patient in the left lateral decubitus position.Auscultation of heart sounds will reveal an accentuated S1 early in mitral stenosis and soft S1 in severe mitral stenosis This occurs since the increased left atrial pressures in early mitral stenosis forces the mobile portion of the mitral valve leaflets far apart. At the onset of ventricular systole, they are forced closed from a relatively far distance resulting in a loud S1. When mitral stenosis becomes more severe and the mitral valve leaflets become significantly more calcified, the mobility of the leaflets decline and they are unable to be separated a great deal, resulting in a soft or even absent S1 heart sound. When pulmonary hypertension develops, the S2 heart sound will be accentuated. A left ventricular S3 is almost always absent in pure MS since LV early diastolic filling is impaired. The significantly increased opening pressures causes an opening snap to occur when the mitral valve leaflets suddenly tense and dome into the LV. This high frequency sound is best heard at the apex.The murmur ofmitral stenosis is low frequency and is referred to as a "rumble". The first part of the murmur of mitral stenosis reflects the pressure gradient between the left atrium and the left ventricle. It begins after S2 with the opening snap and then decrescendos (see picture below) ending in mid diastole. The second part of the murmur occurs just before S1 in a crescendo fashion. This part of the murmur is due to the increased flow of blood through the mitral valve that occurs during atrial contraction. It then makes sense that this aspect of the murmur would be absent if the patient is in atrial fibrillation since active left atrial contraction would be lost.

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