Mitral valve prolapse 545911 223695431 2008-07-05T08:53:08Z 24.80.184.25 /* Sudden death */ clarified grammatical mistake - valve prolapse is associated --> valve prolapse associated {{Infobox_Disease | Name = Mitral valve prolapse | Image = MI Schema schwer Kopie.svg | Caption = | DiseasesDB = 8303 | ICD10 = {{ICD10|I|34|1|i|30}} | ICD9 = {{ICD9|394.0}}, {{ICD9|424.0}} | ICDO = | OMIM = 157700 | MedlinePlus = 000180 | eMedicineSubj = emerg | eMedicineTopic = 316 | MeshID = D008945 }} '''Mitral valve prolapse''' (MVP) is a [[valvular heart disease]] characterized by the displacement of an abnormally thickened [[mitral valve]] leaflet into the [[atria of the heart|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]], [[Endocarditis|infective endocarditis]], and — in rare circumstances — [[cardiac arrest]], usually resulting in sudden [[death]]. == Overview == [[Image:Zenon von Verona3.jpg|thumb|<center>St. [[Zenon of Verona]] wearing a [[mitre]].</center>]] 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 [[atria of the heart|atrium]]. It is composed of two leaflets (one anterior, one posterior) that close when the left ventricle contracts.<ref>{{cite web | last = Women's Heart Foundation, Inc. | first = | title = Mitral Valve Prolapse | url=http://www.womensheartfoundation.org/content/HeartDisease/mitral_valve_prolapse.asp | accessdate = 2007-07-11}}</ref> 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 often causes rupture, and is commonly found in the chordae tendineae attached to the posterior leaflet. Advanced lesions&nbsp;—&nbsp;also commonly involving the posterior leaflet&nbsp;—&nbsp;lead to leaflet folding, inversion, and displacement toward the left atrium. ==History== 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 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 | doi=10.1016/0002-8703(66)90179-7}}</ref> 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]] made proper diagnosis difficult, and hence many subjects without MVP were included in 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 reliable methods of MVP diagnosis—notably [[M-mode echocardiography]]—were used today. In recent years, new criteria have been proposed as an objective measure for diagnosis of MVP using more reliable two- and three-dimensional echocardiography. The disorder has also been classified into a number of subtypes with respect to these criteria. == Subtypes == [[Image:MVP_subtypes.png|framed|378px|Diagnosis of mitral valve prolapse is based on modern [[echocardiography|echocardiographic]] techniques which can pinpoint abnormal leaflet thickening and other related pathology.]] 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. All measurements below refer to adult patients; applying them to children may be misleading. === Classic versus nonclassic === Prolapse occurs when the mitral valve leaflets are displaced more than 2 [[millimetre|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. === Symmetric versus asymmetric === Classical prolapse 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 marked by one leaflet 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. === Flail versus non-flail === Asymmetric prolapse is further subdivided into flail and non-flail. 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. == Diagnosis == [[Echocardiography]] is the most useful method of diagnosing a prolapsed mitral valve. Two- and three-dimensional echocardiography are particularly valuable 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. == Prevalence == Prior to the strict criteria for the diagnosis of mitral valve prolapse, as described above, the incidence of mitral valve prolapse in the general population varied greatly. Some 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 | doi=10.1016/0002-8703(87)90956-2}}</ref> As part of the [[Framingham Heart Study]], the prevalence of mitral valve prolapse in [[Framingham, Massachusetts|Framingham, MA]] was estimated 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 | doi=10.1056/NEJM199907013410101}}</ref> Based on data gathered in the United States, MVP is prevalent in 7% of autopsies.<ref name=webmd /> == Signs and symptoms == Some patients with MVP experience [[heart palpitation]]s, [[atrial fibrillation]], or [[fainting|syncope]], though the prevalence of these symptoms does not differ significantly from the general population. Between 11 and 15% of patients experience moderate [[chest pain]] and [[shortness of breath]]. These symptoms are most likely not caused directly by 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.A statistical relationship has been reported between mitral valve prolapse and bipolar disorder. <ref> AJ Giannini, AE Slaby, JP Gianeeti, MS Darosky. Correlates on physical examination of bipolar patients. Turkish Journal of Biological and Medical Research. 2(1):23-30.1991.</ref>. 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 is a frequent occurrence in individuals with the [[Marfan syndrome]].<ref>{{cite web | last = The National Marfan Foundation | first = | title = Related Disorders: Mitral Valve Prolapse | url=http://www.marfan.org/nmf/GetContentRequestHandler.do?menu_item_id=80 | accessdate = 2007-07-11}}</ref> === Auscultation === Upon [[auscultation]] of an individual with mitral valve prolapse, a mid-systolic click, followed by a late systolic [[heart sounds|murmur]] heard best at the apex is common. ==Mitral valve prolapse syndrome == '''Mitral valve prolapse syndrome''' ('''MVP Syndrome''', '''Barlow's syndrome'''), also referred to as '''mitral valve prolapse dysautonomia''', is an imbalance of the [[autonomic nervous system]] that may be associated with mitral valve prolapse. It is unclear what the underlying etiology is that causes both autonomic dysregulation and the structural abnormalities present in mitral valve prolapse. Symptoms generally attributed to MVP syndrome include palpitations, shortness of breath, and [[fainting]]. 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 often misdiagnosed.<ref name=Fogoros>{{cite web | last = Fogoros | first = Richard N. | title = Mitral Valve Prolapse (MVP) | url=http://heartdisease.about.com/library/weekly/aa073100b.htm | work=Heart Disease | publisher=About.com | accessdate = 2007-07-11}}</ref> This is made more difficult because there is no consensus criteria to diagnose MVP syndrome. Some patients who suffer from mitral valve prolapse syndrome will have [[dysautonomia]] as the cause of their symptoms. Occasionally, supraventricular arrhythmias 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 | doi=10.1046/j.1460-9592.2003.00067.x}}</ref> Mitral valve prolapse syndrome is often misdiagnosed as bipolar disorder . <ref> AJ Giannini, WA Price, RH Loiselle. Prevalence of mitral valve prolapse in bipolar disorder. American Journal of Psychiatry. 141:991-993, 1984.</ref> Therefore, careful evaluation from an experienced center familiar with MVP is advised. == Complications == === Mitral regurgitation === 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 | last = Tanser | first = Paul H. | title = Mitral Valve Prolapse (MVP) | url=http://www.merck.com/mmpe/sec07/ch076/ch076d.html | date= March 2007 | publisher=Merck | accessdate = 2007-07-11}}</ref> === Sudden death === Severe mitral valve prolapse associated with [[arrhythmia]]s and [[atrial fibrillation]] that may progress and lead to [[cardiac arrest|sudden death]] is extremely rare.{{Fact|date=July 2007}} 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]]. == Prognosis == The major predictors of [[death|mortality]] are the severity of mitral regurgitation and the [[ejection fraction]].<ref>{{cite web | last = Rodgers | first = Ellie | title = Mitral Valve Regurgitation | url=http://health.yahoo.com/topic/heart/treatment/article/healthwise/aa143455 | publisher=Healthwise, on Yahoo | date= May 11, 2004 | accessdate = 2007-07-11}}</ref> Generally, MVP is a benign disorder. However, MVP patients with a murmur, not just an isolated click, have a general mortality rate that is increased by 15-20%.<ref name=webmd>{{eMedicine|emerg|316|Mitral Valve Prolapse}}</ref> == 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 blood thinners, such as [[aspirin]] or [[warfarin]]. 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. === Prevention of infective endocarditis=== 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 (1939) |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 }}</ref> == References == <div class="references-small"> <references/> </div> == External links == <!-- BEFORE inserting new links here you should first post it to the talk page, otherwise your edit is likely to be reverted --> * [http://circ.ahajournals.org/cgi/content/full/106/11/1305 Mitral Valve Prolapse Prevalence and Complications] * [http://www.texasheart.org/HIC/Topics/Cond/mvp.cfm Mitral Valve Prolapse - Texas Heart Institute Information Center] * [http://www.mitral.com/mitral-valve-prolapse.shtml Mitral Valve Prolapse - Florida Institute of Cardiovascular Care] * [http://www.echocardiology.org/mitralvalveprolapse.htm Mitral Valve Prolapse - Echocardiographic features] * [http://www.mitralvalverepair.org/ Mitral Valve Repair at The Mount Sinai Hospital] {{Circulatory system pathology}} [[Category:Valvular heart disease]] {{Link FA|es}} [[ca:Prolapse mitral]] [[de:Mitralklappenprolaps]] [[es:Prolapso mitral]] [[fa:افتادگی دریچه میترال]] [[fr:Prolapsus mitral]] [[it:Sindrome da prolasso valvolare mitralico]] [[he:צניחה של השסתום המיטרלי]] [[pl:Zespół Barlowa]] [[pt:Prolapso de valva mitral]] [[ru:Пролапс митрального клапана]]