AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Mitral valve prolapse (MVP), the most common anomaly of the mitral valve apparatus, occurs when one or both mitral valve leaflets excessively billows into the left atrium toward the end of systole. Mitral regurgitation (MR) develops in some patients with MVP, particularly those with more significant prolapse, when the valve edges fail to coapt. An extreme form of prolapse could include chordal rupture, in which the prolapsed mitral valve is flail. Mitral valves excised from patients with severe MR secondary to MVP have large leaflets and show various histologic alterations.

Besides the symptoms attributable to the MR, various neuroendocrine and autonomic disturbances occur in some patients with MVP. In these patients, prolapse may be an epiphenomenon of the underlying autonomic or neurohumoral illness. The term MVP syndrome is often used to refer to the collection of these manifestations. However, in a significant proportion of patients, the mitral valve prolapse is trivial, and no such associated manifestations are present. In these patients, MVP constitutes an essentially benign condition.

Physicians were aware of MVP syndrome as early as 1916, when Sir James MacKenzie described the soldier's heart in spare, thin young men with great vasomotor instability, easy fatigability, breathlessness, and pain over the region of the heart. Kerley first described the syndrome in 1920, and Lincoln described the syndrome in 1928. In 1963, Barlow and colleagues made the first clinical diagnosis of the syndrome as it is known today. The advent of echocardiography led to further advances and formed the basis of current knowledge.

Idiopathic MVP may be congenital in some patients, but recognition may be delayed until adolescence or adulthood. Associated complicating issues include cardiac arrhythmia, heart failure secondary to severe MR (rare), and, occasionally, thromboembolic events. Familial cases are known and occur in an autosomal dominant pattern with variable penetrance and expression (familial MVP).

Pathophysiology

MVP is a heterogeneous disorder and may originate from various underlying causes affecting one or more portions of the mitral valve leaflets, chordae tendineae, papillary muscle, and/or valve annulus. The syndrome may occur in isolation or in association with generalized connective tissue abnormalities, such as Marfan and Ehlers-Danlos syndromes, in which specific enzymatic defects are found. MVP may occur in the context of inflammatory disease such as rheumatic fever or endocarditis.

MVP may be secondary to rupture or dysfunction of the papillary muscles following myocardial infarction or ischemia, rupture of chordae tendineae due to infective endocarditis, or abnormal left ventricular wall motion in the setting of myocardial ischemia and/or primary myocardial disease. In these patients, the posterior leaflet in the floppy valve tends to have a significantly longer basal free-edge length and more frequent chordal rupture compared with patients with postinflammatory disease. A connective tissue abnormality, possibly related to collagen metabolism, may underlie the idiopathic disorder. Abnormalities of collagen and elastic fibers have been documented in floppy mitral valves (FMV). Urokinase-plasminogen activator (PLAU), which is suggested in the pathogenesis of elastin and collagen degradation in arterial aneurysm, has also been implicated in MVP (PLAU T4065C TC genotype). A locus for autosomal dominant MVP has also been described on chromosome 11p15.4.

Electron microscopy of the affected valve leaflets shows a haphazard arrangement, disruption, and fragmentation of collagen fibrils. Myxomatous proliferation of the mitral valve, in which the middle spongiosa layer is predominantly involved, leads to the presence of unusually large amounts of myxomatous material and acid mucopolysaccharide. Degeneration of collagen within the central core of the chordae tendineae may lead to chordal rupture. MVP can also follow rheumatic fever and myocardial infarction, in which case the prolapse is secondary to inflammatory or ischemic chordal rupture, respectively.

Metabolic and neuroendocrine abnormalities also occur in MVP and may separately result in prolapse unrelated to a connective tissue disorder. In such patients, increased norepinephrine and epinephrine may be found. Abnormalities in autonomic and neuroendocrine regulation have been demonstrated, including hyper-response to adrenergic stimulation, parasympathetic abnormalities (vagal withdrawal), altered baroreflex activity, renin-aldosterone regulation abnormalities, decreased intravascular volume, decreased left ventricular volume in upright posture, and atrial natriuretic factor secretion abnormalities.

Frequency

United States

MVP is the most prevalent cardiac valve disorder. MVP is a common finding in otherwise healthy teenagers and young adults, particularly those patients who present with palpitations, chest pain, or dizziness. More than one third of cases in younger children are associated with other congenital heart defects. Reports vary, but 3-5% of pediatric patients likely have clinically significant MVP.

International

Prevalence rates are 1-2% in children and 5-15% in adolescents and young adults. In a series of 278 surgically removed mitral valves with pure regurgitation, MVP was present in 43%.¹ 

Mortality/Morbidity

When present, coexistent abnormalities dictate the risk. Presence of significant MR and prolonged QT interval on ECG may also influence outcome. QT prolongation is slightly more prevalent among patients with MVP and may be associated with repolarization abnormalities and arrhythmia vulnerability. When severe, MR can lead to heart failure.

Mortality is rare in children. Sudden death is also rare and occurs more often in young women with a history of recurrent syncope, sustained supraventricular tachycardia, or complex ventricular tachycardia. Family history of cardiac sudden death often is a risk-stratifying indicator.

Development of MR and the progression of mild or moderate MR to severe MR are important determinants to morbidity. One study showed that the prevalence of MR increased from 29% of patients to 43% of patients during 4.3 years of follow-up.² Other possible complications include congestive cardiac failure, rupture of chordae tendineae, infective endocarditis (in 0.1-0.3 cases per 100 patient years), thromboembolic phenomena including cerebrovascular accidents, and sudden death. Cardiac arrhythmias such as ventricular tachycardia and fibrillation are more common in MVP.

Sex

Some studies show MVP is twice as frequent in females as in males.

Age

Although findings are more frequent in older children and adults, the defect is believed to be present at birth.

CLINICAL

Section 3 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Physical

Most patients are asymptomatic and mitral valve prolapse (MVP) is an incidental auscultatory finding. Beta-blockers may markedly attenuate or abolish the symptoms, a fact that is important to remember while evaluating a patient who is receiving these agents. Findings are more marked when patients are examined in the outpatient department rather than in the inpatient setting, reflecting the contributory role of adrenergic state.

• Chest pain occurs in 10% of patients diagnosed with MVP and may be caused by any of the following factors:
• • Excessive stretching of the chordae tendineae, leading to traction on papillary muscles
  • Coronary microembolism from platelet aggregates and fibrin deposits in the angle between the left atrium and the posterior mitral leaflet
  • Inappropriate tachycardia and excessive postural changes and physical and emotional stresses
  • Hyperadrenergic state, which increases myocardial oxygen demand
  • Coronary artery spasm

• Palpitations
  • Palpitations are present in 7.4% of patients.

  • Occurrence may be related to cardiac arrhythmia, although this has not been conclusively proven.
• Fatigability and dyspnea
• • These often develop upon exertion.

  • The cause may be alterations in centrally modulated breathing cycle control.

• Neuropsychiatric
  • Panic attacks may occur.

  • Nervousness, presyncope, and syncope occur in 0.9% of patients.

  • Thromboembolism, arrhythmia, or vasodepressor-vasovagal problems may be involved.
• Pulse
  • Findings are usually normal.

  • Pulse is occasionally irregular in the presence of premature contractions.

  • Exaggerated tachycardia (high-volume in severe MR) following exertion is not unusual.
• Skeletal abnormalities are observed in two thirds of patients. These do not fit into any of the recognized connective tissue disorders, although an occasional patient may have Marfan or other related syndromes. Common findings are as follows:
• • Hypomastia

  • Thin children

  • Height-to-weight ratio greater than normal

  • Arm span greater than height (dolichostenomelia)

  • Arachnodactyly

  • Scoliosis

  • Narrow anteroposterior chest diameter (straight back)

  • Pectus excavatum or pectus carinatum

  • Cathedral palate

  • Crowding of teeth

  • Joint hypermobility

• Auscultation
• • Apical midsystolic nonejection click and late systolic murmur are the hallmarks, but either may occur alone.

  • Heart sounds are usually normal, but the first heart sound (S1) may be accentuated when prolapse occurs early in systole because of the summation of S1 and mitral click.

  • Multiple clicks occur when prolapse of different leaflets occurs at different times during the systole and may resemble pericardial friction rub.

  • In patients with redundant floppy mitral valves and significant MR, the murmur may be holosystolic and the click may be absent.

  • In cases in which the posterior mitral valve leaflet is prolapsing, the murmur may radiate along the left sternal border to the aortic area, thus mimicking left ventricular outflow tract murmur. If the anterior leaflet prolapses, the murmur radiates to the axilla and the spine.

• Dynamic auscultation
• • In the sitting or standing position in late systole, the click may appear earlier and the murmur may be more prominent. The systolic click moves toward S1 upon standing, often merging with S1 if marked postural tachycardia occurs, and new clicks may appear. If an exaggerated heart rate response occurs, the murmur becomes longer and often louder to holosystolic. Occasionally the murmur is present only in the upright posture.

  • When squatting from standing position, the click and murmur may move back to late systole. Continuous auscultation, while the patient is standing from squatting position, reveals the click and murmur moving back to early systole on a beat-to-beat basis as the heart rate accelerates.

  • A systolic precordial honk or whooping sound may occasionally be heard with the murmur. Often these are heard only in the sitting or standing position and may be limited to a few beats immediately after standing.

  • Dynamic auscultatory changes reflect alterations in the timing of the MVP, the timing and extent of the MR, the expected changes in left ventricular volume, myocardial contractility, and heart rate. In the upright posture, venous return decreases, as does the left ventricular volume. The reflex tachycardia that occurs in the upright position further reduces left ventricular volume. Timing and degree of the prolapse are determined by the position of the mitral leaflets at end diastole, which, in turn, is dependent on the distance from the mitral valve annulus to the attachment of the chordae to papillary muscles. Low left ventricular end-diastolic volume shortens the mitral annular papillary muscle distance, allowing the leaflets to prolapse earlier in systole.

  • Prompt squatting from standing position increases venous return and left ventricular volume; thus, the systolic click and murmur may become late systolic. Squatting, however, may also be associated with an increase in peripheral vascular resistance, which, in turn, increases the tension on the mitral valve apparatus, preferentially directing blood flow into the left atrium, rather than to the peripheral circulation. The late systolic click and murmur then become accentuated in the squatting position.

• Other maneuvers are possible as follows, but none is as practical and helpful as a systematically performed postural dynamic auscultation.
• • Leg elevation

  • Isometric hand grip exercise

  • Valsalva maneuver

  • Application of tourniquets to the extremities

  • Lower body negative pressure or amyl nitrate inhalation

Causes

• Heritable disorders of connective tissue
• • Marfan syndrome
  • Ehlers-Danlos syndrome types I, II, IV
  • Stickler syndrome
  • Polycystic kidney disease, adult type
  • Osteogenesis imperfecta
  • Fragile X syndrome
  • Martin-Bell syndrome
  • Pseudoxanthoma elasticum
  • Periarteritis nodosa

• Skeletal abnormalities
• • Asthenic habitus
  • Straight back syndrome
  • Pectus excavatum
  • Pectus carinatum
  • Cardiac abnormalities
  • Atrial septal defect (ostium secundum), including atrial septal aneurysm, tricuspid valve prolapse, aortic valve prolapse, and Ebstein anomaly of tricuspid valve
  • Holt-Oram syndrome

  • Accessory atrioventricular pathways

  • Coronary artery anomalies

  • Hypertrophic cardiomyopathy

• Other disease
  • Graves disease

  • Thyroiditis

  • Sickle cell disease

  • Muscular dystrophy

  • Myotonic dystrophy

  • Von Willebrand disease
• Several reports suggest magnesium deficiency underlies the disease in some patients.

DIFFERENTIALS

Section 4 of 11  

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• References

Other Problems to be Considered

Congenital mitral regurgitation
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Rheumatic mitral regurgitation
Tricuspid valve prolapse

WORKUP

Section 5 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Perform blood and other laboratory tests as dictated by the condition of the patient.

Imaging Studies

• Radiography
• • Chest radiography findings are normal. Cardiac size and pulmonary venous congestion appear when MR is severe.
  • Skeletal surveys reveal any abnormalities.


• Echo-Doppler studies
• • This is an essential tool to identify the presence and magnitude of mitral valve prolapse (MVP), the thickness of mitral valve leaflets, mitral annulus size, chordae tendineae length, and left ventricular and left atrial size and function. The test also reveals any associated heart diseases.
  • Multiple views of the mitral valve annulus are essential, and the echo-Doppler findings have to be correlated with clinical data.
  • Two-dimensional, real-time echocardiographic pictures from parasternal long-axis window show the mitral valve leaflets coming together in systole and billowing into the left atrium beyond the atrioventricular junction. The medial aspect of the anterior leaflet and middle scallop of the posterior leaflet are visualized from this view. The lateral scallop of posterior leaflet can be seen only from the apical 4-chamber window, and, at times, MVP can be focal. The echocardiographic description of the MVP should include structural changes, such as leaflet thickening, redundancy, annular dilatation, and chordal elongation. A varying degree of noncoaptation of the leaflets is present, and MR can be identified by Doppler-color, pulse wave, and continuous wave. The MR jet can be defined, and its magnitude and direction estimated. The size of the left atrium and left ventricle are increased in the presence of moderate-to-severe MR.
  • Three-dimensional echocardiography is reportedly very helpful in delineating the prolapse and associated regurgitation. It has also been reported to provide information that helps in surgical repair.
  • Transesophageal echocardiography has also improved the identification of leaflet morphology, assisting surgical repair.
  • M-mode echocardiography shows a characteristic posterior movement of the posterior mitral leaflet during mid or late systole or pansystolic prolapse of both anterior and posterior mitral leaflets toward the left atrium. With the availability of 2-dimensional and Doppler studies, MVP should no longer be diagnosed solely on M-mode pictures.
  • These studies, particularly transesophageal echocardiography, also help identify potential embolic sources in patients with focal neurologic symptoms or signs.
  • Findings are always interpreted in the context of the clinical evaluation by dynamic auscultation. The diagnostic accuracy improves by use of a constellation of findings, which include structural and functional changes. Patients with echocardiographic criteria for MVP, without evidence of thickened redundant leaflets or significant MR, require careful review before MVP is diagnosed. Mere sagging of anterior leaflet in the 4-chamber view does not indicate MVP. Patients with typical auscultatory findings may be diagnosed even with questionable echocardiographic findings.
  • Rarely, patients with MVP may have typical echocardiographic findings but no abnormality on auscultation. Patients with suggestive symptoms and no auscultatory findings, who have nonspecific echocardiographic changes, present a real challenge and may require periodic reevaluation before a firm diagnosis can be made. Family history could be of help in some of these patients.


• Stress scintigraphy: Myocardial perfusion scintigraphy (eg, using thallium-201) during exercise may help identify the rare patient with MVP and myocardial ischemia.

Other Tests

• Electrocardiography
• • Results are usually normal; however, in about one half of children and adolescents, the findings may reveal inverted or biphasic T waves, especially in leads II, III, aVF, and/or V5-6. The T-wave abnormalities may vary at different times in the same patient and may improve with exercise or with beta-blocker therapy.
  • Arrhythmias described at rest or during exercise include premature atrial (23.6%) or ventricular (27.3%) contractions, supraventricular tachycardia, and conduction abnormalities. Patients with MVP demonstrate a higher frequency of left-sided accessory pathways. More serious findings include ventricular tachycardia and fibrillation.
  • A higher incidence of arrhythmia may be due to a prolonged QT interval. Diastolic depolarization of muscle fibers in the anterior mitral leaflet in response to stretch may also have a role.
  • Slow response action potentials originating in the atrial-like muscle fibers in the mitral valve leaflets can lead to sustained rhythmic action that penetrates the cardiac chambers.

• Phonocardiography: This was previously used as an adjunct to confirm the auscultatory findings.

Procedures

• Ambulatory 24-hour electrocardiogram
• • A Holter monitor may help identify the nature and frequency of arrhythmic activity.
  • Premature ventricular beats (38%), multiform couplets, and tachyarrhythmias (8%) are usual findings.

• Exercise testing
• • This is useful in patients with palpitations and exercise-related symptoms.
  • Premature ventricular beats (16%), ventricular tachycardia (4%), and supraventricular ectopy are common findings. Ventricular fibrillation is a rare finding.

• Cardiac catheterization and angiography
• • These tests are generally restricted to patients with MVP and severe MR who may require valve repair or replacement.
  • Associated coronary artery disease can also be confirmed or excluded.
  • A left ventricular angiogram, taken in the right anterior oblique view, best shows the posterior leaflet. A left anterior oblique projection shows the anterior leaflet.
  • Other abnormalities that may be revealed include dilatation, decreased systolic contraction, calcification of the mitral annulus, and poor contraction of the basal portion of the left ventricle.

• Electrophysiology
• • Indications for electrophysiology (EPS) are similar to those in general clinical practice.
  • EPS is useful in the presence of supraventricular tachycardia because accessory atrioventricular pathways are common in patients with MVP. In this subset of patients, EPS is important because radiofrequency ablation can be performed during the same procedure, with a very high curative success rate.

• Tilt test: Upright tilt studies with blood pressure and cardiac rhythm monitoring may be valuable in patients with light-headedness or syncope when vasodepressor-vasovagal reaction is suspected and confirmation of clinical symptoms is desired.

Histologic Findings

Mitral valves excised from patients with severe MR secondary to MVP have large leaflets and show various alterations. The most specific, fundamental, and characteristic histologic changes are (1) collagen dissolution and disruption in the pars fibrosa of the mitral valve leaflet and (2) replacement of the dense collagenous fibrosa by loose myxomatous connective tissue with high acid mucopolysaccharide content.

Similar histologic abnormalities are observed in chordae tendineae. Scanning electron photomicrographs demonstrate surface folds and focal loss of endothelial cells on mitral valve leaflets obtained from patients with severe MVP and significant MR. These surface abnormalities may predispose to thromboembolic complications and/or infectious endocarditis. Continuous pressure and stress on the leaflets and chordae tendineae during left ventricular systole contribute to gradual progression of these histologic changes.

TREATMENT

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• References

Medical Care

In childhood, the condition is not progressive, and specific therapy is not indicated for the vast majority. Asymptomatic patients with isolated mitral systolic clicks need only counseling and reassurance.

Avoid excessive use of caffeine, cigarettes, alcohol, and prescription or over-the-counter drugs that contain stimulants such as epinephrine or ephedrine to minimize catecholamine and cyclic adenosine monophosphate (AMP) stimulation. Prevention of volume depletion before, during, and immediately after exercise may help. Subacute bacterial endocarditis antibiotic prophylaxis coverage for at-risk procedures is indicated in patients with mitral valve prolapse (MVP) and MR. See Antibiotic Prophylactic Regimens for Endocarditis.

Additional dental care recommended for patients at risk for infective endocarditis includes the following:

• Regular toothbrushing after eating
• No cookies, sweets, or sweet drinks between meals
• Regular dental checks every 6 months
• Fluoride supplements in locations where the fluoride in drinking water is less than 0.3 ppm for children younger than 2 years or less than 0.7 ppm for children younger than 2 years
• Dental treatments (more than 2) scheduled at an interval of 14 days or longer

Surgical Care

Recent advances have made reconstructive mitral valve surgery feasible in patients with congestive heart failure, severe MR secondary to MVP, or both. For details of surgical intervention, results, postoperative care, and complications of MR, see Mitral Regurgitation.

Consultations

A multidisciplinary approach is preferable, with a team from the following specialties:

• Pediatrics
• Pediatric cardiology
• Radiology
• Genetics
• Cardiothoracics

• Physiotherapy

• Family medicine

• Orthopedics

Activity

• A gradual return to exercise may be tolerated.
• In the absence of studies on the effect of exercise on the progression of MVP, the best approach at present is based on common sense and good clinical judgment.
• Patients with symptoms of syncope, presyncope, or palpitations upon exertion should undergo thorough evaluations and avoid competitive sports for at least 6 months after the last significant episode.
• In the presence of significant MR, limitations apply as for any other cause of MR.
• Coexisting aortic root dilatation and aortic regurgitation can further limit activity.
• Patients with cardiac arrhythmia should have periodic exercise tests performed and ambulatory ECG recordings obtained while doing the type of exercise they are likely to undertake.

• Sudden death is extremely uncommon in MVP.

MEDICATION

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Medical strategies for mitral valve prolapse (MVP)

• Anticongestive heart failure therapy

• Antibiotic prophylaxis during surgery, dental, and genitourinary procedures - Only necessary if associated mitral regurgitation (See Antibiotic Prophylactic Regimens for Endocarditis.)

• Antiarrhythmic therapy - May be indicated in patients with documented and/or symptomatic arrhythmia, dependent on findings of noninvasive and/or invasive electrophysiologic testing

• Beta-blockers - May be beneficial for symptom prevention, reduction in ectopy, treatment of vasodepressor syncope, panic attacks, or antiarrhythmic therapy

• Antiplatelet therapy - Used in patients with thromboembolic episodes

• ACE inhibitors - Used in patients with significant MR

• Low-dose aspirin and/or anticoagulant therapy - Considered in patients with thromboembolic episodes

Drug Category: Beta-adrenergic blocking agents

These agents block the beta-adrenergic receptor and are modulators of the autonomic system. They inhibit chronotropic, inotropic and vasodilatory responses to beta-adrenergic stimulation.

Drug Category: Antiplatelet agents

These drugs are used for secondary prevention of thrombotic cerebrovascular or cardiac disease.

Drug Name	Dipyridamole (Persantine)
Description	Acts by decreasing platelet aggregation. Inhibits thrombus formation in the arterial side of circulation.
Adult Dose	300-600 mg/d PO divided tid/qid
Pediatric Dose	2.5 mg/kg PO bid
Contraindications	Documented hypersensitivity; peptic ulcer disease; hereditary coagulopathies
Interactions	Theophylline may decrease hypotensive effects; antiplatelet activity may increase heparin toxicity; enhances and prolongs action of adenosine
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in hypotension; medication has peripheral vasodilating effects; exacerbates heart failure, asthma, angina, and MI; adverse effects include gastrointestinal upset, dizziness, headache, hot flushes, tachycardia, and bleeding tendency

Drug Category: Diuretics

These drugs are used to release retained fluid and lower preload.

Drug Name	Spironolactone (Aldactone)
Description	Potassium-sparing diuretic. Acts on the distal convoluted tubule of the kidney as an aldosterone antagonist. Has synergistic action with furosemide.
Adult Dose	100-200 mg/d PO
Pediatric Dose	0.5-1.5 mg/kg PO bid
Contraindications	Documented hypersensitivity; hyperkalemia, hyponatremia, severe renal impairment, Addison disease
Interactions	Risk of hyperkalemia with ACE inhibitors, cyclosporin, or potassium supplements
Pregnancy	D - Unsafe in pregnancy
Precautions	Caution in renal and hepatic impairment; may cause gastrointestinal upset, hyponatremia, hyperkalemia, lethargy, confusion, impotence, gynecomastia, and is carcinogenic in rodents

Drug Name	Amiloride (Midamor)
Description	Pyrazine-carbonyl-guanidine unrelated chemically to other known antikaliuretic or diuretic agents. Potassium-conserving (antikaliuretic) drug that, compared with thiazide diuretics, possesses weak natriuretic, diuretic, and antihypertensive activity. Acts directly on the distal renal tubule, usually used along with a potassium-losing diuretic.
Adult Dose	5-10 mg PO bid
Pediatric Dose	<20 kg: 0.2 mg/kg PO bid; not to exceed 10 mg/d >20 kg: Administer as in adults
Contraindications	Documented hypersensitivity; elevated serum potassium levels, >5.5 mEq/L; impaired renal function, acute or chronic renal insufficiency, and evidence of diabetic nephropathy; monitor electrolytes closely if there is evidence of renal functional impairment, BUN level >30 mg/100 mL or serum creatinine levels >1.5 mg/100 mL
Interactions	Risk of hyperkalemia with ACE inhibitors, cyclosporine, or potassium supplements; decreased effect with NSAIDs
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Potassium retention associated with use of an antikaliuretic agent accentuated in presence of renal impairment and may result in rapid development of hyperkalemia; monitor serum potassium level, mild hyperkalemia usually not associated with abnormal ECG; gastrointestinal upset, dry mouth, skin rash, confusion, and postural hypotension may develop

Drug Category: ACE inhibitors

These agents reduce afterload and decrease myocardial remodeling, which worsens chronic heart failure.

Drug Category: Cardiac glycoside

These agents provide symptomatic improvement in heart failure.

FOLLOW-UP

Section 8 of 11  

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Further Inpatient Care

• Admission is seldom required, except in the case of complications or for consideration of surgical intervention.

Further Outpatient Care

• Patients require continued follow-up care and evaluation into adult life.
• Repeat evaluations every 3-5 years to identify any progression.
• Infective endocarditis prophylaxis is indicated in patients with mitral valve prolapse (MVP) and MR while undergoing at-risk procedures. For more information, see Antibiotic Prophylaxis Regimens for Endocarditis.
• Patients with accessory pathways should have detailed EPS studies and radiofrequency ablation of the accessory pathway.
• Coronary artery anomalies should be excluded in patients with chest pain before they participate in sports.
• Mild prolapse while on echocardiogram, in the absence of clinical findings (15-20% of patients), does not indicate true MVP syndrome. Parents and patients need to be reassured.

In/Out Patient Meds

• Anti–heart failure medications
• Propranolol
• Aspirin
• Dipyridamole
• Warfarin
• Antibiotics for endocarditis prophylaxis

Complications

• Progression or appearance of MR is one of the main complications. Over 4.3 years, approximately 14% of patients developed MR.
• Congestive cardiac failure
• Rupture of chordae tendineae
• Infective endocarditis, in 0.1-0.3 cases per 100 patient years
• Thromboembolic phenomena including cerebrovascular accidents and sudden death
• Cardiac arrhythmia
• Ventricular tachycardia and fibrillation

Prognosis

• The condition is not progressive in childhood, and specific therapy is not indicated for the vast majority.
• Progression to significant MR or sudden death is rare.
• Asymptomatic patients with isolated mitral systolic clicks need only counseling and reassurance.

Patient Education

• Careful explanation of the clinical findings and the nature of MVP help to reassure the anxious patient.
• Normal activity can be allowed if MR is not severe
• Antibiotic prophylaxis during surgery and dental procedures is only necessary if associated MR is present.
• The vast majority of patients with MVP remain asymptomatic for their entire lives and require observation every few years for reassurance.
• Patients with orthostatic syncope secondary to dehydration should take extra salt and water during and following sport activities and competition.
• Pregnancy requires infective endocarditis prophylaxis during delivery. Other implications are based on the severity of MR.
• For excellent patient education resources, visit eMedicine's Heart Center. Also, see eMedicine's patient education article Mitral Valve Prolapse.

MISCELLANEOUS

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Medical/Legal Pitfalls

• Failure to make the diagnosis
• Failure to fully investigate patients who are symptomatic
• Failure to restrict exercise in patients who are symptomatic
• Failure to recognize the higher risk of arrhythmia during anesthesia and the perioperative period
• Patients with mitral valve prolapse (MVP) syndrome require a careful history and thorough physical examination because of the possibility of misinterpreting history, physical findings, borderline lab test results, and nonspecific ECG or echocardiography changes.
• Overtreatment
• Overdiagnosis
• Any unexplained symptoms should be viewed with due concern and investigated.

Special Concerns

• Diagnosis should include the type of prolapse (late systolic, holosystolic, anterior, or posterior leaflet), thickness of MV leaflets, size of mitral annulus, and the left ventricular and left atrial size and function. The diagnosis should also include presence, severity, and timing of MR; define jet direction and magnitude; and clearly list associated abnormalities.
• Patients with orthostatic syncope secondary to dehydration should take excess salt and water during and following sport activities and competition.
• Patients are more sensitive to volume depletion; hence chronic diuretic therapy should be avoided.

MULTIMEDIA

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Media file 1:  Chest radiograph of 5-year-old girl with mitral valve prolapse (MVP) and mild mitral regurgitation. The radiograph shows cardiomegaly and normal pulmonary vasculature.
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Media type:  X-RAY

Media file 2:  Two-lead electrocardiogram of a child with mitral valve prolapse (MVP) showing T-Wave inversion in leads III and aVF.
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Media type:  ECG

Media file 3:  Two-dimensional echocardiographic picture taken from the parasternal long-axis view showing prolapse of both anterior and posterior mitral valve leaflets into the left atrium at systole.
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Media type:  Photo

Media file 4:  Color-Doppler echocardiography of a child with mitral valve prolapse showing jet of mitral regurgitation.
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Media type:  Photo

Media file 5:  M-mode echocardiographic picture of mitral valve prolapse showing pansystolic prolapse of both anterior and posterior mitral leaflets toward left atrium.
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Media type:  Photo

Media file 6:  Plain radiograph of the left hand of a 10-year-old boy with marfanoid syndrome and mitral valve prolapse (MVP) showing the long thin metacarpals. The metacarpal index is longer than normal.
	View Full Size Image
Media type:  X-RAY

REFERENCES

Section 11 of 11

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
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