Mitral Stenosis

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Background

Mitral stenosis (MS) is characterized by obstruction to left ventricular inflow at the level of mitral valve due to structural abnormality of the mitral valve apparatus. The most common cause of mitral stenosis is rheumatic fever. Other less common etiologies include congenital mitral stenosis, malignant carcinoid disease, systemic lupus erythematosus, rheumatoid arthritis, mucopolysaccharidoses of the Hunter-Hurler phenotype, Fabry disease, Whipple disease, and methysergide therapy. The association of atrial septal defect with rheumatic mitral stenosis is called Lutembacher syndrome.

A number of conditions can simulate the physiology of mitral stenosis: severe nonrheumatic mitral annular calcification, infective endocarditis with large vegetation, left atrial myxoma, ball valve thrombus, or cor triatriatum.

Stenosis of the mitral valve typically occurs decades after the episode of acute rheumatic carditis. Acute insult leads to formation of multiple inflammatory foci (Aschoff bodies, perivascular mononuclear infiltrate) in the endocardium and myocardium. Small vegetations along the border of the valves may also be observed. With time, the valve apparatus becomes thickened, calcified, and contracted, and commissural adhesion occurs, ultimately resulting in stenosis.

Whether the progression of valve damage is due to hemodynamic injury of the already affected valve apparatus or to the chronic inflammatory nature of the rheumatic process is unclear.

Pathophysiology

The normal mitral valve orifice area is approximately 4-6 cm2. As the orifice size decreases, the pressure gradient across the mitral valve increases to maintain adequate flow.

Patients will not experience valve-related symptoms until the valve area is 2-2.5 cm2 or less, at which point moderate exercise or tachycardia may result in exertional dyspnea from the increased transmitral gradient and left atrial pressure.

Severe mitral stenosis occurs with a valve area of less than 1 cm2. As the valve progressively narrows, the resting diastolic mitral valve gradient, and hence left atrial pressure, increases. This leads to transudation of fluid into the lung interstitium and dyspnea at rest or with minimal exertion. Hemoptysis may occur if the bronchial veins rupture and left atrial dilatation increases the risk for atrial fibrillation and subsequent thromboembolism.

Pulmonary hypertension may develop as a result of (1) retrograde transmission of left atrial pressure, (2) pulmonary arteriolar constriction, (3) interstitial edema, or (4) obliterative changes in the pulmonary vascular bed (intimal hyperplasia and medial hypertrophy). As pulmonary arterial pressure increases, right ventricular dilation and tricuspid regurgitation may develop, leading to elevated jugular venous pressure, liver congestion, ascites, and pedal edema.

Left ventricular end-diastolic pressure and cardiac output are usually normal in the person with isolated mitral stenosis. As the severity of stenosis increases, the cardiac output becomes subnormal at rest and fails to increase during exercise. Approximately one third of patients with rheumatic mitral stenosis have depressed left ventricular systolic function as a result of chronic rheumatic myocarditis. The presence of concomitant mitral regurgitation, systemic hypertension, aortic stenosis, or myocardial infarction can also adversely affect left ventricular function and cardiac output.

Epidemiology

Frequency

United States

The prevalence of rheumatic disease in developed nations is steadily declining with an estimated incidence of 1 in 100,000.

International

The prevalence of rheumatic disease is higher in developing nations than in the United States.[1] In India, for example, the prevalence is approximately 100-150 cases per 100,000, and in Africa the prevalence is 35 cases per 100,000.

Mortality/Morbidity

Mitral stenosis is a progressive disease consisting of a slow, stable course in the early years followed by an accelerated course later in life. Typically, there is a latent period of 20-40 years from the occurrence of rheumatic fever to the onset of symptoms. Once symptoms develop, it is almost a decade before they become disabling. In some geographic areas, mitral stenosis progresses more rapidly, presumably due to either a more severe rheumatic insult or repeated episodes of rheumatic carditis due to new streptococcal infections, which results in severe symptomatic mitral stenosis in the late teens and early 20s.

In the asymptomatic or minimally symptomatic patient, survival is greater than 80% at 10 years. When limiting symptoms occur, 10-year survival is less than 15% in the patient with untreated mitral stenosis. When severe pulmonary hypertension develops, mean survival is less than 3 years. Most (60%) patients with severe untreated mitral stenosis die of progressive pulmonary or systemic congestion, but others may suffer systemic embolism (20-30%), pulmonary embolism (10%), or infection (1-5%).

Sex

Two thirds of all patients with rheumatic mitral stenosis are female.

Age

The onset of symptoms usually occurs between the third and fourth decade of life.

History

Physical

Causes

See Background.

Laboratory Studies

Perform routine baseline tests such as CBC count, electrolyte status, and renal and liver function tests.

Imaging Studies

Chest radiographic findings suggestive of mitral stenosis include left atrial enlargement (eg, double shadow in the cardiac silhouette, straightening of left cardiac border due to the large left atrial appendage, and upward displacement of the mainstem bronchi), prominent pulmonary vessels, redistribution of pulmonary vasculature to the upper lobes, mitral valve calcification, and interstitial edema (Kerley A and B lines).

Echocardiography is the most specific and sensitive method of diagnosing and quantifying the severity of mitral stenosis. Using a transthoracic 2-dimensional echocardiogram, Doppler study, and color-flow Doppler imaging, the anatomic abnormalities of the stenotic valve (ie, thickening, mobility, motion, calcification), involvement of the subvalvular apparatus and the characteristic fusion of the commissures can be well defined.[2]

With echocardiography, the size of the mitral valve orifice can be precisely quantified. Important information about the ventricular and atrial chamber sizes, the presence of a left atrial thrombus, measurement of transvalvular gradient, and pulmonary arterial pressure can also be obtained.

With the use of Doppler echocardiography, sufficient information can be obtained to develop a therapeutic plan, and, consequently, most patients do not require invasive procedures such as cardiac catheterization.

Transesophageal echocardiography (TEE) provides better quality images than transthoracic echocardiography (TTE) and is more accurate in assessing the anatomic features of the valve and the presence of left atrial appendage thrombus. Recent studies showed that mitral valve area planimetry is feasible in the majority of patients with rheumatic mitral stenosis using 3-dimensional TEE; also, 3-dimensional TEE allows excellent assessment of commissural fusion[3] and commissural opening after catheter-balloon commisurotomy.

See the image and videos below.


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Transesophageal echocardiogram with continuous wave Doppler interrogation across the mitral valve demonstrating an increased mean gradient of 16 mm Hg....


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Magnified view of the mitral valve in apical 4-chamber view revealing restricted opening of both leaflets.


View Video

Transesophageal echocardiogram in an apical 3-chamber view showing calcification and doming of the anterior mitral leaflet and restricted opening of both leaflets.


View Video

Transesophageal echocardiogram in an apical 3-chamber view with color Doppler interrogation of the mitral valve revealing aliasing, which is consistent with increased gradient across the mitral valve secondary to stenosis. Also shown in this image, a posteriorly directed jet of severe mitral regurgitation.

Other Tests

In patients with moderate-to-severe mitral stenosis, the ECG can show signs of left atrial enlargement (P wave duration in lead II >0.12 seconds, P wave axis of +45 to -30 marked terminal negative component to the P wave in V1 [1 mm wide and 1 mm deep]) and, commonly, atrial fibrillation. A mean QRS axis in the frontal plane is greater than 80 and an R-to-S ratio of greater than 1 in lead V1 indicates the presence of right ventricular hypertrophy. As the severity of the pulmonary hypertension increases, the mean QRS axis in the frontal plane moves toward the right.

Procedures

Cardiac catheterization was routine performed in the past. However, the accuracy of echocardiographic findings has resulted in only selective use of catheterization. Cardiac catheterization is now indicated in the following situations:

Histologic Findings

See Background.

Medical Care

The goal of medical treatment for mitral stenosis is to reduce recurrence of rheumatic fever, provide prophylaxis for infective endocarditis, reduce symptoms of pulmonary congestion (eg, orthopnea, paroxysmal nocturnal dyspnea), control the ventricular rate if atrial fibrillation is present, and prevent thromboembolic complications.

Because rheumatic fever is the primary cause of mitral stenosis, secondary prophylaxis against group A beta-hemolytic streptococci (GAS) is recommended.[4] Duration of prophylaxis depends on the number of previous attacks, the time elapsed since the last attack, the risk of exposure to GAS infections, the age of the patient, and the presence or absence of cardiac involvement. Penicillin is the agent of choice for secondary prophylaxis, but sulfadiazine or a macrolide or azalide are acceptable alternatives in individuals allergic to penicillin (Tables 1 and 2).

A recent study done in Europe on 315 patients with rheumatic mitral stenosis showed a significantly slower progression of rheumatic mitral stenosis in patients treated with statins compared with patients not taking statins. These findings could have an important impact in the early medical therapy of patients with rheumatic heart disease.[5]

The current American Heart Association (AHA) recommendations[6] no longer suggest infective endocarditis prophylaxis for patients with rheumatic heart disease. However, the maintenance of optimal oral health care remains an important component of an overall healthcare program. For the relatively few patients with rheumatic heart disease in whom infective endocarditis prophylaxis remains recommended, such as those with prosthetic valves or prosthetic material used in valve repair, the current AHA recommendations should be followed. These recommendations advise the use of an agent other than a penicillin to prevent infective endocarditis in those receiving penicillin prophylaxis for rheumatic fever because oral alpha-hemolytic streptococci are likely to have developed resistance to penicillin.

The indication for antibiotic prophylaxis for endocarditis has also been significantly reduced in the 2012 European Society of Cardiology (ESC) guidelines, although they recommend considering antibiotic prophylaxis for high-risk procedures in high-risk patients.[7]

Initial symptoms of pulmonary congestion can be safely treated by diuretics. Dietary sodium restriction and nitrates decrease preload and can be of additional benefit. Careful use of beta-blockers in patients with a normal sinus rhythm can prolong the diastolic filling time and thus decrease in left atrial pressure. In general, afterload reduction should be avoided as it can cause hypotension.

Atrial fibrillation is common in mitral stenosis and often leads to a rapid ventricular rate with reduced diastolic filling time and increased left atrial pressure. The ventricular rate can be slowed acutely by the administration of intravenous beta-blocker or calcium channel blocker therapy (diltiazem or verapamil). The rate and/or rhythm can be controlled long-term with oral beta-blockers, calcium channel blockers, amiodarone, or digoxin.

In the patient with mild mitral stenosis and recent-onset (< 6 mo) atrial fibrillation, conversion to sinus rhythm can be accomplished with pharmacologic agents or electrical cardioversion. In this circumstance, anticoagulation therapy should be given for at least 3 weeks prior to cardioversion. Alternatively, a TEE can be performed to exclude the presence of left atrial thrombus, prior to cardioversion. Patients who are successfully converted to sinus rhythm should receive long-term anticoagulation and antiarrhythmic drugs. Warfarin should be used for anticoagulation. The novel anticoagulants dabigatran and rivaroxaban have been recently approved for nonvalvular atrial fibrillation; these drugs have not been evaluated in patients with heart valve disease.[8]

According to the 2012 ESC/European Association for Cardio-Thoracic Surgery (EACTS) guidelines, anticoagulant therapy with a target INR in the upper half of the range 2 to 3 is indicated in patients with either permanent or paroxysmal atrial fibrillation. In patients with sinus rhythm, anticoagulation is indicated in those with prior embolism, or those in whom a thrombus is present in the left atrium.[7]

Surgical correction of the mitral stenosis is indicated if embolization is recurrent, despite adequate anticoagulation therapy.

Table 1. Duration of Secondary Rheumatic Fever Prophylaxis


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See Table

Table 2. Secondary Prevention of Rheumatic Fever (Prevention of Recurrent Attacks)


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See Table

Surgical Care

Surgical therapy for mitral stenosis consists of mitral valvotomy (which can be either surgical or percutaneous) or mitral valve replacement. The surgical mitral valvotomy approach can be through an closed or open technique; the latter technique is rarely used, except in developing countries, and has largely been replaced by the percutaneous balloon commissurotomy[2] .

Asymptomatic patients with moderate or severe mitral stenosis (mitral valve area < 1.5 cm2) and a suitable valve should be considered for percutaneous balloon commissurotomy if the pulmonary arterial systolic pressure is ≥50 mm Hg at rest or ≥60 mm Hg with exercise, or pulmonary capillary wedge pressure is ≥25 mm Hg with exercise.[9]

Symptomatic patients with moderate or severe mitral stenosis (mitral valve area < 1.5 cm2) and suitable valve are also candidates for percutaneous balloon commissurotomy.

ESC/EACTS guidelines recommend percutaneous balloon commissurotomy in symptomatic patients with favorable characteristics, symptomatic patients with contraindications or high risk for surgery, symptomatic patients with unfavorable anatomy but without unfavorable clinical charcteristics, and in asymptomatic patients without unfavorable characteristics and a high thromboembolic risk and/or a high risk of hemodynamic decompensation.[7]

Contraindications to percutaneous mitral commissurotomy include mitral valve area >1.5 cm2, left atrial thrombus, more than mild mitral regurgitation, severe or bicommissural calcification, absence of commissural fusion, severe concomitant aortic valve disease or severe combined tricuspid stenosis and regurgitation, and concomitant coronary artery disease requiring bypass surgery.[7]

If percutaneous balloon commissurotomy is not an option, patients should be referred for surgical repair or mitral valve replacement.

Consultations

Key members of a multidisciplinary team for structural heart valve disease management include primary cardiologists, interventional cardiologists, cardiac surgeons, noninvasive and heart failure cardiologists, echocardiographers and cardiac imaging specialists, cardiac anesthesiologists, nurse practitioners, physician assistants, research coordinators, administrators, dietary and rehabilitation specialists, and social workers. Each component will need to develop and implement specific protocols depending on the individual patient and specific technical procedure.[11]

Diet

The patient should start a low-salt diet if pulmonary vascular congestion is present.

Activity

In most patients with mitral stenosis, recommendations for exercise are symptom limited. Patients should be encouraged to pursue a low-level aerobic exercise program for maintenance of cardiovascular fitness.

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Digoxin (Lanoxicaps, Lanoxin)

Clinical Context:  Cardiac glycoside with direct inotropic effects and indirect effects on the cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Amiodarone (Cordarone, Pacerone)

Clinical Context:  May inhibit AV conduction and sinus node function. Prolongs action potential and refractory period in myocardium and inhibits adrenergic stimulation. Prior to administration, control ventricular rate and CHF (if present) with digoxin or calcium channel blockers.

Class Summary

These agents alter the electrophysiologic mechanisms responsible for arrhythmia.

Diltiazem (Cardizem CD, Dilacor, Tiazac, Cardizem LA)

Clinical Context:  During depolarization, inhibits calcium ions from entering slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.

Class Summary

In specialized conducting and automatic cells in the heart, calcium is involved in the generation of the action potential. Calcium channel blockers inhibit movement of calcium ions across the cell membrane, depressing both impulse formation (automaticity) and conduction velocity.

Warfarin (Coumadin)

Clinical Context:  Interferes with hepatic synthesis of vitamin K–dependent coagulation factors. Used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders. Tailor dose to maintain an INR of 2-3.

Heparin

Clinical Context:  Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin. Does not actively lyse but is able to inhibit further thrombogenesis. Prevents reaccumulation of clot after spontaneous fibrinolysis.

Class Summary

These agents prevent recurrent or ongoing thromboembolic occlusion of the vertebrobasilar circulation.

Metoprolol (Lopressor, Toprol XL)

Clinical Context:  Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions. During IV administration, carefully monitor blood pressure, heart rate, and ECG.

Class Summary

These agents inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation.

Penicillin G benzathine (Bicillin L-A, Permapen)

Clinical Context:  Interferes with synthesis of cell wall mucopeptides during active multiplication, which results in bactericidal activity. Used to treat syphilis and for prophylaxis of recurrent streptococcal infections.

Class Summary

Must cover all likely pathogens in the context of this clinical setting. Use as prophylaxis against streptococcal infections.

Furosemide (Lasix)

Clinical Context:  Increases excretion of water by interfering with chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Dose must be individualized to patient. Depending on response, administer at increments of 20-40 mg, no sooner than 6-8 h after previous dose, until desired diuresis occurs. When treating infants, titrate with increments of 1 mg/kg/dose until a satisfactory effect is achieved.

Class Summary

Diuretics are used for treatment of pulmonary congestion. Treatment may improve symptoms of venous congestion through elimination of retained fluid and preload reduction.

Further Outpatient Care

Deterrence/Prevention

Table 3. Primary Prevention of Rheumatic Fever (Treatment of Streptococcal Tonsillopharyngitis*)


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Complications

Prognosis

Author

Claudia Dima, MD, FACC, Interventional Cardiologist, St Joseph's Hospital and Medical Center of Phoenix, AZ

Disclosure: Nothing to disclose.

Coauthor(s)

Kenneth B Desser, MD, Clinical Professor, Director of Cardiology Fellowship, Banner Good Samaritan Medical Center, Phoenix, Arizona

Disclosure: Nothing to disclose.

Specialty Editors

L Michael Prisant, MD, FACC, FAHA, Cardiologist, Emeritus Professor of Medicine, Medical College of Georgia

Disclosure: Boehringer-Ingelheim Honoraria Speaking and teaching

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Steven J Compton, MD, FACC, FACP, FHRS, Director of Cardiac Electrophysiology, Alaska Heart Institute, Providence and Alaska Regional Hospitals

Disclosure: Nothing to disclose.

Amer Suleman, MD, Private Practice

Disclosure: Nothing to disclose.

Chief Editor

Richard A Lange, MD, Professor and Executive Vice Chairman, Department of Medicine, Director, Office of Educational Programs, University of Texas Health Science Center at San Antonio

Disclosure: Nothing to disclose.

Additional Contributors

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Holger P Salazar, MD, Senthil Nachimuthu, MD, FACP, and Kiruthika Balasundaram, MBBS to the development and writing of this article.

References

  1. Marcus RH, Sareli P, Pocock WA, et al. The spectrum of severe rheumatic mitral valve disease in a developing country. Correlations among clinical presentation, surgical pathologic findings, and hemodynamic sequelae. Ann Intern Med. Feb 1 1994;120(3):177-83. [View Abstract]
  2. Bruce CJ, Nishimura RA. Newer advances in the diagnosis and treatment of mitral stenosis. Curr Probl Cardiol. Mar 1998;23(3):125-92. [View Abstract]
  3. Schlosshan D, Aggarwal G, Mathur G, Allan R, Cranney G. Real-time 3D transesophageal echocardiography for the evaluation of rheumatic mitral stenosis. JACC Cardiovasc Imaging. Jun 2011;4(6):580-8. [View Abstract]
  4. [Guideline] Gerber MA, Baltimore RS, Eaton CB, Gewitz M, Rowley AH, Shulman ST, et al. Prevention of rheumatic fever and diagnosis and treatment of acute Streptococcal pharyngitis: a scientific statement from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee of the Council on Cardiovascular Disease in the Young, the Interdisciplinary Council on Functional Genomics and Translational Biology, and the Interdisciplinary Council on Quality of Care and Outcomes Research: endorsed by the American Academy of Pediatrics. Circulation. Mar 24 2009;119(11):1541-51. [View Abstract]
  5. Antonini-Canterin F, Moura LM, Enache R, Leiballi E, Pavan D, Piazza R. Effect of hydroxymethylglutaryl coenzyme-a reductase inhibitors on the long-term progression of rheumatic mitral valve disease. Circulation. May 18 2010;121(19):2130-6. [View Abstract]
  6. [Guideline] Nishimura RA, Carabello BA, Faxon DP, Freed MD, Lytle BW, O'Gara PT. ACC/AHA 2008 Guideline update on valvular heart disease: focused update on infective endocarditis: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. Aug 19 2008;52(8):676-85. [View Abstract]
  7. [Guideline] Vahanian A, Alfieri O, Andreotti F, Antunes MJ, Barón-Esquivias G, Baumgartner H, et al. Guidelines on the management of valvular heart disease (version 2012): The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. Oct 2012;33(19):2451-96. [View Abstract]
  8. Wann LS, Curtis AB, Ellenbogen KA, et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (update on dabigatran): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. Mar 15 2011;57(11):1330-7. [View Abstract]
  9. Feldman T. Rheumatic Mitral Stenosis. Curr Treat Options Cardiovasc Med. Apr 2000;2(2):93-104. [View Abstract]
  10. Rahimtoola SH. Choice of Prosthetic Heart Valve in Adults An Update. J Am Coll Cardiol. Jun 1 2010;55(22):2413-2426. [View Abstract]
  11. Holmes DR Jr, Mack MJ. Transcatheter valve therapy a professional society overview from the american college of cardiology foundation and the society of thoracic surgeons. J Am Coll Cardiol. Jul 19 2011;58(4):445-55. [View Abstract]
  12. Horstkotte D, Niehues R, Strauer BE. Pathomorphological aspects, aetiology and natural history of acquired mitral valve stenosis. Eur Heart J. Jul 1991;12 Suppl B:55-60. [View Abstract]
  13. [Guideline] Bonow RO, Carabello BA, Chatterjee K, de Leon AC Jr, Faxon DP, Freed MD, et al. 2008 focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for the management of patients with valvular heart disease). Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. Sep 23 2008;52(13):e1-142. [View Abstract]
  14. Bonow RO, Otto CM. Valvular heart disease. In: Libby P, Bonow RO, Mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 2. 8th ed. Philadelphia, PA: WB Saunders; 2008:1646-1657.
  15. Carabello BA. Modern management of mitral stenosis. Circulation. Jul 19 2005;112(3):432-7. [View Abstract]

Apical 4-chamber view demonstrating restricted opening of the anterior and posterior mitral valve leaflet with diastolic doming of anterior leaflet with left atrial enlargement.

Apical 4-chamber view with color Doppler demonstrating aliasing in the atrial side of the mitral valve consistent with increased gradient across the valve. This figure also shows mitral regurgitation and left atrial enlargement.

Transesophageal echocardiogram with continuous wave Doppler interrogation across the mitral valve demonstrating an increased mean gradient of 16 mm Hg consistent with severe mitral stenosis.

Magnified view of the mitral valve in apical 4-chamber view revealing restricted opening of both leaflets.

Transesophageal echocardiogram in an apical 3-chamber view showing calcification and doming of the anterior mitral leaflet and restricted opening of both leaflets.

Transesophageal echocardiogram in an apical 3-chamber view with color Doppler interrogation of the mitral valve revealing aliasing, which is consistent with increased gradient across the mitral valve secondary to stenosis. Also shown in this image, a posteriorly directed jet of severe mitral regurgitation.

M-mode across the mitral valve showing a flat E-F slope resulting from elevated left atrial pressure throughout diastole due to a significant gradient across the mitral valve. Increased thickness and calcification of anterior leaflet of the mitral valve and decreased opening of the anterior and posterior leaflets in diastole are also shown.

Parasternal long-axis view demonstrating calcification and doming in diastole of the anterior valve leaflet and mild restriction in the opening of posterior mitral valve leaflet.

Apical 4-chamber view demonstrating restricted opening of the anterior and posterior mitral valve leaflet with diastolic doming of anterior leaflet with left atrial enlargement.

Transesophageal echocardiogram with continuous wave Doppler interrogation across the mitral valve demonstrating an increased mean gradient of 16 mm Hg consistent with severe mitral stenosis.

Apical 4-chamber view with color Doppler demonstrating aliasing in the atrial side of the mitral valve consistent with increased gradient across the valve. This figure also shows mitral regurgitation and left atrial enlargement.

Magnified view of the mitral valve in apical 4-chamber view revealing restricted opening of both leaflets.

Transesophageal echocardiogram in an apical 3-chamber view showing calcification and doming of the anterior mitral leaflet and restricted opening of both leaflets.

Transesophageal echocardiogram in an apical 3-chamber view with color Doppler interrogation of the mitral valve revealing aliasing, which is consistent with increased gradient across the mitral valve secondary to stenosis. Also shown in this image, a posteriorly directed jet of severe mitral regurgitation.

CategoryDuration After Last AttackRating*
Rheumatic fever with carditis and residual heart disease (persistent valvular disease† )10 y or until age 40 y (whichever is longer); sometimes lifelong prophylaxisIC
Rheumatic fever with carditis but no residual heart disease (no valvular disease† )10 y or until age 21 y (whichever is longer)IC
Rheumatic fever without carditis5 y or until age 21 y (whichever is longer)IC
*Rating indicates classification of recommendation and level of evidence (eg, IC indicates Class I, level of Evidence C).

†Clinical or echocardiographic evidence.

AgentDoseModeRating*
Benzathine penicillin GChildren 27 kg (60 lb): 600,000 U

Patients >27 kg: 1,200,000 every 4 wk†

IntramuscularIA
Penicillin V250 mg bidOralIB
SulfadiazineChildren 27 kg: 0.5 g qd

Patients >27 kg: 1 g qd

OralIB
Macrolide or azalide (for individuals allergic to penicillin and sulfadiazine)VariableOralIC
*Rating indicates classification of recommendation and level of evidence (eg, IA indicates Class I, level of Evidence A).

†In high-risk situations, administration every 3 weeks is justified and recommended.

AgentDoseModeDurationRating
Penicillins
Penicillin V (phenoxymethyl penicillin)Children 27 kg (60 lb): 250 mg bid or tid

Patients >27 kg: 500 mg bid or tid

Oral10 dIB
Amoxicillin50 mg/kg qd (maximum 1 g)Oral10 dIB
Benzathine penicillin GChildren 27 kg (60 lb): 600,000 U

Patients >27 kg: 1,200,000 U

IntramuscularOnceIB
For individuals allergic to penicillin
Narrow-spectrum cephalosporin (cephalexin, cefadroxil)VariableOral10 dIB
Clindamycin20 mg/kg/d divided in 3 doses (maximum 1.8 g/d)Oral10 dIIaB
Azithromycin12 mg/kg qd (maximum 500 mg)Oral5 dIIaB
Clarithromycin15 mg/kg/d divided bid (maximum 250 mg bid)Oral10 dIIaB
*Sulfonamides, trimethoprim, tetracyclines, and fluoroquinolones are not acceptable.

† Rating indicates classification of recommendation and level of evidence (eg, IB indicates Class I, level of Evidence B)