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| '''For patient information click [[{{PAGENAME}} (patient information)|here]]'''
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| {{Infobox_Disease | | {{Infobox_Disease |
| | Name = Mitral valve prolapse | | | Name = Mitral valve prolapse |
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| | OMIM = 157700 | | | OMIM = 157700 |
| | MedlinePlus = 000180 | | | MedlinePlus = 000180 |
| | eMedicineSubj =
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| | eMedicineTopic =
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| | MeshID = D008945 | | | MeshID = D008945 |
| }} | | }} |
| {{Mitral valve prolapse}} | | {{Mitral valve prolapse}} |
| {{CMG}}; '''Associate Editor-In-Chief:''' {{CZ}}
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| | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' |
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| | {{CMG}}; '''Associate Editor-In-Chief:''' {{CZ}} |
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| ==Overview==
| | {{SK}} Barlow syndrome; floppy mitral valve; systolic click—murmur syndrome; redundant cusp syndrome; billowing mitral valve syndrome |
| '''Mitral valve prolapse''' ('''MVP''') is a [[valvular heart disease]] characterized by the displacement of an abnormally thickened [[mitral valve]] leaflet into the left atrium during [[systole]]. In its nonclassic form, MVP carries a low risk of complications. In severe cases of classic MVP, complications include [[mitral regurgitation]] and [[infective endocarditis]].
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| The [[mitral valve]], so named because of its resemblance to a bishop's miter, is the [[heart valve]] that prevents the backflow of [[blood]] from the left [[Ventricle (heart)|ventricle]] into the [[left atrium]]. It is composed of two leaflets (one anterior, one posterior) that close when the left ventricle contracts.<ref>{{cite web
| | == [[Mitral valve prolapse overview|Overview]] == |
| | last = Women's Heart Foundation, Inc.
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| | first =
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| | title = Mitral Valve Prolapse
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| | url=http://www.womensheartfoundation.org/content/HeartDisease/mitral_valve_prolapse.asp
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| | accessdate = 2007-07-11}}</ref>
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| Each leaflet is composed of three layers of [[biological tissue|tissue]]: the ''atrialis'', ''fibrosa'', and ''spongiosa''. Patients with classic mitral valve prolapse have excess [[connective tissue]] that thickens the spongiosa and separates [[collagen]] bundles in the fibrosa. This is due to an excess of [[dermatan sulfate]], a [[glycosaminoglycan]]. This weakens the leaflets and adjacent tissue, resulting in increased leaflet area and elongation of the [[chordae tendineae]]. Elongation of the chordae may be associated with chordae rupture, and is commonly found in the chordae tendineae attached to the posterior leaflet. Advanced lesions — also commonly involving the posterior leaflet — lead to leaflet folding, inversion, and displacement toward the [[left atrium]].
| | == [[Mitral valve prolapse historical perspective|Historical Perspective]] == |
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| ==History== | | == [[Mitral valve prolapse classification|Classification]] == |
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| The term ''mitral valve prolapse'' was coined by [[J. Michael Criley]] in 1966 and gained acceptance over the other descriptor of "billowing" of the mitral valve, as originally described by JB Barlow.<ref name="Barlow-1966">{{cite journal | author=Barlow JB, Bosman CK. | title=Aneurysmal protrusion of the posterior leaflet of the mitral valve. An auscultatory-electrocardiographic syndrome. | journal=Am Heart J | year=1966 | volume=71 | issue=2 | pages=166-78 | pmid=4159172}}</ref>. Barlow had postulated that mitral valve prolapse was due to an aneurysm of the mitral leaflet and Criley demonstrated that it was instead due to displacement of the leaflet that led to the condition.
| | == [[Mitral valve prolapse pathophysiology|Pathophysiology]] == |
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| For many years, mitral valve prolapse was a poorly understood anomaly associated with a wide variety of both related and seemingly unrelated signs and symptoms, including late [[systole|systolic]] [[heart murmur|murmurs]], inexplicable [[panic attack]]s, and [[polythelia]] (extra [[nipple]]s). Recent studies suggest that these symptoms were incorrectly linked to MVP because the disorder was simply over-diagnosed at the time. Continuously-evolving criteria for diagnosis of MVP with [[echocardiography]] have made the diagnosis more rigorous and specific. As a result, there may have been many patients who would not currently be classified as having MVP who were included in original studies of the disorder and its prevalence. In fact, some modern studies report that as many as 55% of the population would be diagnosed with MVP if older, less specific criteria for the diagnosis of MVP, such as M-mode echocardiography—were applied today.
| | == [[Mitral valve prolapse causes|Causes]] == |
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| In recent years, new objective diagnostic criteria for MVP have been proposed based upon two- and three-dimensional echocardiography. The disorder has also been classified into a number of subtypes with respect to these echocardiographic criteria.
| | == [[Mitral valve prolapse epidemiology and demographics|Epidemiology and Demographics]] == |
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| <div align="left">
| | == [[Mitral valve prolapse natural history, complications and prognosis|Natural History, Complications and Prognosis]] == |
| <gallery heights="175" widths="175">
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| Image:Zenon von Verona3.jpg|St. Zenon of Verona wearing a mitre.
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| </gallery>
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| </div>
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| == Subtypes ==
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| Prolapsed mitral valves are classified into several subtypes, based on leaflet thickness, concavity, and type of connection to the mitral annulus. Subtypes can be described as classic, nonclassic, symmetric, asymmetric, flail, or non-flail.
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| '''Note: all measurements below refer to adult patients and applying them to children may be misleading.'''
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| <div align="left">
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| <gallery heights="175" widths="400">
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| Image:MVP_subtypes.png|Diagnosis of mitral valve prolapse is based on modern [[echocardiography|echocardiographic]] techniques which can pinpoint abnormal leaflet thickening and other related pathology.
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| </gallery>
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| </div>
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| === Classic versus nonclassic ===
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| Prolapse occurs when the mitral valve leaflets are displaced more than 2 mm above the mitral annulus high points. The condition can be further divided into classic and nonclassic subtypes based on the thickness of the mitral valve leaflets: up to 5 mm is considered nonclassic, while anything beyond 5 mm is considered classic MVP.
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| === Symmetric versus asymmetric ===
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| Classic MVP may be subdivided into symmetric and asymmetric, referring to the point at which leaflet tips join the mitral annulus. In symmetric coaptation, leaflet tips meet at a common point on the annulus. Asymmetric coaptation is characterized by one leaflet being displaced toward the atrium with respect to the other. Patients with asymmetric prolapse are susceptible to severe deterioration of the mitral valve, with the possible rupture of the chordae tendineae and the development of a flail leaflet.
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| === Flail versus non-flail ===
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| Asymmetric prolapse is further subdivided into flail and non-flail prolapse. Flail prolapse occurs when a leaflet tip turns outward, becoming concave toward the left atrium, causing the deterioration of the mitral valve. The severity of flail leaflet varies, ranging from tip eversion to chordal rupture. Dissociation of leaflet and chordae tendineae provides for unrestricted motion of the leaflet (hence "flail leaflet"). Thus patients with flail leaflets have a higher prevalence of [[mitral regurgitation]] than those with the non-flail subtype.
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| == Diagnosis == | | == Diagnosis == |
| Two- and three-dimensional [[echocardiography]] are valuable in the diagnosis of MVP as they allow visualization of the mitral leaflets relative to the mitral annulus. This allows measurement of the leaflet thickness and their displacement relative to the annulus. Thickening of the mitral leaflets >5 mm and leaflet displacement >2 mm indicates classic mitral valve prolapse.
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| ==Differential Diagnosis of Underlying Causes==
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| * Acquired
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| * Congenital
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| * [[Marfan's Syndrome]]
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| * Myxomatous generation of the mitral valve
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| * Papillary muscle infarction
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| * Papillary muscle trauma
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| == Prevalence ==
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| Prior to the development of rigorous criteria for the diagnosis and classification of mitral valve prolapse, as described above, the incidence of mitral valve prolapse in the general population varied significantly. Studies estimated the incidence of mitral valve prolapse at 5 to 15 percent or even higher.<ref name="Levy-1987">{{cite journal | author=Levy D, Savage D. | title=Prevalence and clinical features of mitral valve prolapse. | journal=Am Heart J | year=1987 | volume=113 | issue=5 | pages=1281-90 | pmid=3554946}}</ref>
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| As part of the [[Framingham Heart Study]], more modern estimates of the prevalence of mitral valve prolapse have been lower at 2.4%. There was a near-even split between classic and nonclassic MVP, with no significant age or sex discrimination.<ref name="Freed-1999">{{cite journal | author=Freed LA, Levy D, Levine RA, Larson MG, Evans JC, Fuller DL, Lehman B, Benjamin EJ. | title=Prevalence and clinical outcome of mitral-valve prolapse. | journal=N Engl J Med | year=1999 | volume=341 | issue=1 | pages=1-7 | pmid=10387935}}</ref> Based on data gathered in the United States, MVP is prevalent in 7% of autopsies.<ref name=webmd />
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| ==Diagnosis==
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| === Signs and symptoms ===
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| While mitral valve prolapse has been associated with a variety of symptoms it should be noted that the frequency of these symptoms does not differ significantly from that of the general population. Therefore the causal link between mitral valve prolapse and these associated symptoms is not clear. Some patients with MVP experience [[heart palpitation]]s, [[atrial fibrillation]], or [[fainting|syncope]]. Between 11% and 15% of patients experience moderate [[chest pain]] and [[shortness of breath]]. These symptoms may not be directly attributable to the prolapsing mitral valve, but rather by the mitral regurgitation that often results from prolapse. In addition, the American Heart Association has linked anxiety and panic attack disorders to Mitral Valve Prolapse, although the causal nature of this association is not clear.
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| For unknown reasons, MVP patients tend to have a low [[body mass index]] (BMI) and are typically leaner than individuals without MVP.<ref name="Freed-1999" /> MVP occurs more frequently among individuals with the [[Marfan syndrome]].<ref>{{cite web
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| | last = The National Marfan Foundation
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| | first =
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| | title = Related Disorders: Mitral Valve Prolapse
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| | url=http://www.marfan.org/nmf/GetContentRequestHandler.do?menu_item_id=80
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| | accessdate = 2007-07-11}}</ref>
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| === Auscultation ===
| | [[Mitral valve prolapse history and symptoms|History and Symptoms]] | [[Mitral valve prolapse physical examination|Physical Examination]] | [[Mitral valve prolapse chest x-ray|Chest X ray]] | [[Mitral valve prolapse CT|CT]] | [[Mitral valve prolapse MRI|MRI]] | [[Mitral valve prolapse echocardiography|Echocardiography]] | [[Mitral valve prolapse left ventriculography|Left ventriculography]] |
| Upon [[auscultation]] a mid-systolic click is present, followed by a late systolic [[heart sounds|murmur]] which is best heard at the apex.
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| ===Echocardiography===
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| ==== 2D Echo features ====
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| The leaflets and chordae are thick and reduntant. Reduced tensile strength leads to progressive elongation or rupture of chordae. Ruptured chordae appear as flail segments.
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| To diagnose mitral valve prolapse, the following criteria should be fulfilled - Movement of any part of either leaflet more than 2mm behind the annular plane in parasternal long axis view and movement of point of co-aptation behind the annular plane in apical 4 chamber view. Mitral regurgitation can result in enlarged LA size.
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| ==== Doppler ====
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| Colour flow mapping and CW doppler shows predominantly late systolic mitral regurgitation.
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| ====M Mode Echocardiography====
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| {|
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| |[[Image:MItral Valve Prolapse.jpg|thumb|450px|left|MItral Valve Prolapse.jpg M Mode]] | |
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| ===Left Ventriculography===
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| {{#ev:googlevideo|1357398178641849422}}
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| ==Mitral valve prolapse syndrome==
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| '''Mitral valve prolapse syndrome''' ('''MVP Syndrome'''), also referred to as '''mitral valve prolapse dysautonomia''', is thought to represent an imbalance of the [[autonomic nervous system]] in association with mitral valve prolapse. The underlying etiology that causes both autonomic dysregulation and the structural abnormalities present in mitral valve prolapse is unknown. Most patients who suffer from mitral valve prolapse syndrome may have an underlying [[dysautonomia]] as the cause of their symptoms. In particular, supraventricular arrhythmias such as those observed with MVP syndrome are associated with increased parasympathetic tone.<ref name="Terechtchenko-2003">{{cite journal | author=Terechtchenko L, Doronina SA, Pochinok EM, Riftine A. | title=Autonomic tone in patients with supraventricular arrhythmia associated with mitral valve prolapse in young men. | journal=Pacing Clin Electrophysiol | year=2003 | volume=26 | issue=1 Pt 2 | pages=444-6 | pmid=12687863}}</ref>
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| Symptoms generally attributed to MVP syndrome include [[palpitations]], [[shortness of breath]], and [[fainting|syncope]]. Because of the low specificity of these symptoms, and the fact that there is significant overlap in the causes of these symptoms with sequelae of significant [[mitral regurgitation]] often seen with mitral valve prolapse, MVP syndrome is most likely over-diagnosed.<ref name=Fogoros>{{cite web
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| | last = Fogoros
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| | first = Richard N.
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| | title = Mitral Valve Prolapse (MVP)
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| | url=http://heartdisease.about.com/library/weekly/aa073100b.htm
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| | work=Heart Disease
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| | publisher=About.com
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| | accessdate = 2007-07-11}}</ref> The uncertainty regarding the frequency of this syndrome may in part be due to the fact that there is no consensus criteria to diagnose MVP syndrome.
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| == Complications ==
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| === Mitral regurgitation ===
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| Mitral valve prolapse is frequently associated with mild [[mitral regurgitation]],<ref>{{cite journal |author=Kolibash AJ |title=Progression of mitral regurgitation in patients with mitral valve prolapse |journal=Herz |volume=13 |issue=5 |pages=309-17 |year=1988 |pmid=3053383 |doi=}}</ref> where blood aberrantly flows from the left ventricle into the left atrium during [[systole]]. Occasionally MVP patients experience severe regurgitation, often due to [[chordae tendineae]] rupture.<ref>{{cite web
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| | last = Tanser
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| | first = Paul H.
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| | title = Mitral Valve Prolapse (MVP)
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| | url=http://www.merck.com/mmpe/sec07/ch076/ch076d.html
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| | date= March 2007
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| | publisher=Merck
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| | accessdate = 2007-07-11}}</ref>
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| === Sudden death ===
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| Severe mitral valve prolapse is associated with [[arrhythmia]]s and [[atrial fibrillation]] that may progress and lead to [[cardiac arrest|sudden death]]. As there is no evidence that a prolapsed valve itself contributes to such arrythmias,<ref name=Fogoros /> these complications are more likely due to mitral regurgitation and [[congestive heart failure]].
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| == Prognosis ==
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| The major predictors of [[death|mortality]] are the severity of mitral regurgitation and the [[ejection fraction]].<ref>{{cite web
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| | last = Rodgers
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| | first = Ellie
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| | title = Mitral Valve Regurgitation
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| | url=http://health.yahoo.com/topic/heart/treatment/article/healthwise/aa143455
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| | publisher=Healthwise, on Yahoo
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| | date= May 11, 2004
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| | accessdate = 2007-07-11}}</ref> Generally, MVP is a benign disorder. However, MVP patients with a murmur, not just an isolated click, may have a poorer prognosis.<ref name=webmd>{{eMedicine|emerg|316|Mitral Valve Prolapse}}</ref>
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| == Treatment == | | == Treatment == |
| Most patients only need reassurance. Those with mitral valve prolapse and symptoms of dysautonomia ([[palpitations]], [[chest pain]]) may often benefit from [[beta-blockers]] (e.g., [[propranolol]]). Patients with prior [[stroke]] and/or [[atrial fibrillation]] may require anticoagulation is, such as [[aspirin]] or [[warfarin]].
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| Mitral valve prolapse associated with severe mitral regurgitation can be treated with repair or [[mitral valve replacement|surgical replacement]] of the mitral valve. Repair of the mitral valve is always preferable to replacement and should be performed by surgeons that are skilled in the procedure. Current ACC/AHA guidelines suggest that early repair of mitral valve, performed in centers of surgical excellence, should be considered even in patients without symptoms of [[heart failure]]. Symptomatic patients, those with evidence of diminished left ventricular function or left ventricular dilatation need urgent attention.
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| === Prevention of infective endocarditis===
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| People with mitral valve prolapse are at higher risk of [[infective endocarditis]] (bacterial infection of the heart tissue), as a result of certain non-sterile procedures such as teeth cleaning and biopsy during colonoscopy. However, an April 2007 study by the [[American Heart Association]] has determined that the risks of prescribing [[antibiotics]] outweigh the benefits of antibiotic prophylaxis before an invasive procedure (such as dental surgery). Therefore, MVP patients who have taken prophylactic antibiotics routinely in the past may no longer need them.<ref>{{cite journal |author=Wilson W, Taubert KA, Gewitz M, ''et al'' |title=Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group |journal=Journal of the American Dental Association |volume=138 |issue=6 |pages=739-45, 747-60 |year=2007 |pmid=17545263 |doi= |url=http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.106.183095v1.pdf |format=PDF
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| }}</ref>
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| == References ==
| | [[Mitral valve prolapse medical therapy|Medical Therapy]] | [[Mitral valve prolapse surgery|Surgery]] | [[Mitral valve prolapse tertiary prevention|Tertiary Prevention]] |
| {{Reflist|2}}
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| == External links == | | == External links == |
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| * [http://circ.ahajournals.org/cgi/content/full/106/11/1305 Mitral Valve Prolapse Prevalence and Complications] | | * [http://circ.ahajournals.org/cgi/content/full/106/11/1305 Mitral Valve Prolapse Prevalence and Complications] |
| * [http://www.tmc.edu/thi/mvp.html Mitral Valve Prolapse - Texas Heart Institute Information Center]
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| * [http://www.mitral.com/mitral-valve-prolapse.shtml Mitral Valve Prolapse - Florida Institute of Cardiovascular Care]
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| * [http://www.echocardiology.org/mitralvalveprolapse.htm Mitral Valve Prolapse - Echocardiographic features]
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| * [http://www.mitralvalverepair.org/ Mitral Valve Repair at The Mount Sinai Hospital]
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| {{Circulatory system pathology}} | | {{Circulatory system pathology}} |
