adj.

僧帽弁の、僧帽状の

関: mitral valve

WordNet

relating to or resembling the miter worn by some clerics
of or relating to or located in or near the mitral valve; "mitral insufficiency"

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/17 21:48:31」(JST)

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The mitral valve (also known as the bicuspid valve or left atrioventricular valve) is a dual-flap (bi- from the Latin, meaning double, and mitral- from the Latin, meaning shaped like a mitre) valve in the heart that lies between the left atrium (LA) and the left ventricle (LV). The mitral valve (not to be confused with the congenital bicuspid aortic valve) and the tricuspid valve are known collectively as the atrioventricular valves because they lie between the atria and the ventricles of the heart and control the flow of blood.

During diastole, a normally-functioning mitral valve opens as a result of increased pressure from the left atrium as it fills with blood (preloading). As atrial pressure increases above that of the left ventricle, the mitral valve opens. Opening facilitates the passive flow of blood into the left ventricle. Diastole ends with atrial contraction, which ejects the final 20% of blood that is transferred from the left atrium to the left ventricle. This amount of blood is known as end-diastolic volume (EDV), and the mitral valve closes at the end of atrial contraction to prevent a reversal of blood flow.

Structure

Operative view of the mitral valve with a chordal rupture "fail" of the anterior leaflet

The mitral valve is typically 4–6 cm² in area. It has two cusps, or leaflets, (the anteromedial leaflet and the posterolateral leaflet) that guard the opening. The opening is surrounded by a fibrous ring known as the mitral valve annulus. (The orientation of the two leaflets resemble a bishop's mitre, whence the valve receives its name.^[1]) The anterior cusp protects approximately two-thirds of the valve (imagine a crescent moon within the circle, where the crescent represents the posterior cusp). Note that although the anterior leaflet takes up a larger part of the ring and rises higher, the posterior leaflet has a larger surface area. These valve leaflets are prevented from prolapsing into the left atrium by the action of tendons attached to the posterior surface of the valve, chordae tendineae.

The inelastic chordae tendineae are attached at one end to the papillary muscles and the other to the valve cusps. Papillary muscles are fingerlike projections from the wall of the left ventricle. Chordae tendineae from each muscle are attached to both leaflets of the mitral valve. Thus, when the left ventricle contracts, the intraventricular pressure forces the valve to close, while the tendons keep the leaflets coapting together and prevent the valve from opening in the wrong direction (thus preventing blood to flow back to the left atrium). Each chord has a different thickness. The thinnest ones are attached to the free leaflet margin, whereas thickest ones (strut chords) are attached quite away from the free margin. This disposition has important effects on systolic stress distribution physiology ^[2]

Function

During left ventricular diastole, after the pressure drops in the left ventricle due to relaxation of the ventricular myocardium, the mitral valve opens, and blood travels from the left atrium to the left ventricle. About 70 to 80% of the blood that travels across the mitral valve occurs during the early filling phase of the left ventricle. This early filling phase is due to active relaxation of the ventricular myocardium, causing a pressure gradient that allows a rapid flow of blood from the left atrium, across the mitral valve. This early filling across the mitral valve is seen on doppler echocardiography of the mitral valve as the E wave.

After the E wave, there is a period of slow filling of the ventricle.

Left atrial contraction (left atrial systole) (during left ventricular diastole) causes added blood to flow across the mitral valve immediately before left ventricular systole. This late flow across the open mitral valve is seen on doppler echocardiography of the mitral valve as the A wave. The late filling of the LV contributes about 20% to the volume in the left ventricle prior to ventricular systole, and is known as the atrial kick.

The mitral annulus changes in shape and size during the cardiac cycle. It is smaller at the end of atrial systole due to the contraction of the left atrium around it, like a sphincter. This reduction in annulus size at the end of atrial systole may be important for the proper coapting of the leaflets of the mitral valve when the left ventricle contracts and pumps blood.^[3] Leaking valves can be corrected by mitral valve annuloplasty, a common surgical procedure that aims at restoring proper leaflet adjustment.

Clinical significance

The closing of the mitral valve and the tricuspid valve constitutes the first heart sound (S1). It is not the valve closure itself which produces the sound but the sudden cessation of blood flow, when the mitral and tricuspid valves close.

There are some valvular heart diseases that affect the mitral valve. Mitral stenosis is a narrowing of the valve. This can be heard as an opening snap in a heart sound which is not normally present.

Classic mitral valve prolapse is caused by an excess of connective tissue that thickens the spongiosa layer of the cusp and separates collagen bundles in the fibrosa. This weakens the cusps and adjacent tissue, resulting in an increased cuspal area and lengthening of the chordae tendineae. Elongation of the chordae tendineae often causes rupture, commonly to the chordae attached to the posterior cusp. Advanced lesions—also commonly involving the posterior leaflet—lead to leaflet folding, inversion, and displacement toward the left atrium.^[4]

A valve prolapse can result in mitral insufficiency which is a regurgitation or backflow of blood due to the incomplete closure of the valve. Surgery can be performed to replace or repair a damaged valve. A less invasive method is that of mitral valvuloplasty which uses a balloon catheter to open up a stenotic valve.

Additional images

Section of the heart showing the ventricular septum. (Bicuspid valve visible at center.)
Front of thorax, showing surface relations of bones, lungs (purple), pleura (blue), and heart (red outline). Heart valves are labeled with "B", "T", "A", and "P".
Apical view of valves
Cross-sectional view of mitral valve between left atrium (upper chamber) and left ventricle (lower chamber), which shows parts of walls of left atrium and left ventricle that are next to the mitral valve.
Mitral valve
Mitral valve

References

^ mitral valve, Stedman's Online Medical Dictionary at Lippincott Williams and Wilkins
^ Nazari S, Carli F, Salvi S, et al. (Apr 2000). "Patterns of systolic stress distribution on mitral valve anterior leaflet chordal apparatus. A structural mechanical theoretical analysis". J Cardiovasc Surg (Torino) 41 (2): 193–202. PMID 10901521.
^ Pai RG, Varadarajan P, Tanimoto M (2003). "Effect of atrial fibrillation on the dynamics of mitral annular area". The Journal of Heart Valve Disease 12 (1): 31–7. PMID 12578332. Retrieved 2010-03-04.
^ Playford, David; Weyman, Arthur (2001). "Mitral valve prolapse: time for a fresh look". Reviews in Cardiovascular Medicine 2 (2): 73–81. PMID 12439384.

External links

Anatomy figure: 20:07-03 at Human Anatomy Online, SUNY Downstate Medical Center — "Valves of the heart"
Cardiac Valve Animations - Perioperative Interactive Education Group — Cardiac valve animations

UpToDate Contents

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1. 慢性僧帽弁閉鎖不全症のマネージメントの概要 overview of the management of chronic mitral regurgitation
2. Clinical manifestations and diagnosis of chronic mitral regurgitation
3. 重度の慢性一次性僧帽弁閉鎖不全症における矯正手術の適応 indications for corrective surgery in severe chronic primary mitral regurgitation
4. 経カテーテル僧帽弁修復 transcatheter mitral valve repair
5. 慢性僧帽弁閉鎖不全症の血管拡張療法 vasodilator therapy in chronic mitral regurgitation

English Journal

Physical therapy for a child with sudden-onset choreoathetosis: a case report.

Smith HJ.Author information Physical Therapy Department, Franciscan Hospital for Children, Brighton, Massachusetts.AbstractPURPOSE: This case report describes the physical therapy examination, intervention, and outcomes for a 5-year-old girl who developed choreoathetosis following mitral valve repair.
Pediatric physical therapy : the official publication of the Section on Pediatrics of the American Physical Therapy Association.Pediatr Phys Ther.2014 Spring;26(1):85-93. doi: 10.1097/PEP.0000000000000010.
PURPOSE: This case report describes the physical therapy examination, intervention, and outcomes for a 5-year-old girl who developed choreoathetosis following mitral valve repair.CASE DESCRIPTION: This child was admitted to an inpatient short-term rehabilitation program with marked choreoathetosis a
PMID 24356324

Associations of pulse pressure index with left ventricular filling pressure and diastolic dysfunction in patients with chronic kidney disease.

Lee WH, Hsu PC, Chu CY, Chen SC, Su HM, Lin TH, Lee CS, Yen HW, Voon WC, Lai WT, Sheu SH.Author information Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.AbstractBACKGROUND: Patients with chronic kidney disease (CKD) often have poor vascular compliance and poor left ventricular diastolic dysfunction (LVDD). The pulse pressure index (PPI) defined as ((systolic blood pressure - diastolic blood pressure)/systolic blood pressure) reflects vascular compliance. Vascular compliance is reportedly associated with left ventricular diastolic function. This study of CKD patients investigated whether PPI correlates with the ratio of transmitral E wave velocity (E) to early diastole mitral annulus velocity (Ea) or with LVDD.
American journal of hypertension.Am J Hypertens.2014 Mar;27(3):454-9. doi: 10.1093/ajh/hpt228. Epub 2013 Dec 10.
BACKGROUND: Patients with chronic kidney disease (CKD) often have poor vascular compliance and poor left ventricular diastolic dysfunction (LVDD). The pulse pressure index (PPI) defined as ((systolic blood pressure - diastolic blood pressure)/systolic blood pressure) reflects vascular compliance. Va
PMID 24326205

Diastolic dysfunction and cardiovascular risk in old subjects: possible association with NAFLD?

Gianotti G1, Cenni A2, Bianchi G2, Masetti M2, Zappoli P2, Muscari A2, Zoli M2; Pianoro Study Group.Collaborators (48)Zoli M, Bianchi G, Magalotti D, Muscari A, Berzigotti A, Castaldini N, Dapporto S, Drago G, Giannoni C, Ludovico C, Montesi F, Nicolino F, Ramilli S, Sbano D, Zappoli P, Chianese R, Ferri F, Passerini G, Maietta P, Tentoni C, Nerozzi E, Ravaioli C, Masi P, Negrini I, Cavrini G, Mattivi A, Colombo M, Pandolfi P, Ligabue A, Dini L, Zacchini A, Melli A, Sonnino J, Ajuti A, Bacci S, Bruni L, Chiarini G, Corradini G, Nucci F, Ongaro E, Scandellari E, Selva S, Saliera S, Cavazza G, Grazia A, Mezzini MP, Mignogna D, Torchi E.
Archives of gerontology and geriatrics.Arch Gerontol Geriatr.2014 Mar-Apr;58(2):188-95. doi: 10.1016/j.archger.2013.10.012. Epub 2013 Nov 5.
Non-alcoholic fatty liver disease (NAFLD) is frequently associated with metabolic syndrome (MS) and may represent a cardiovascular (CV) risk factor. Functional cardiac abnormalities have been reported in patients with NAFLD. The aim of this paper is to investigate whether these findings are present
PMID 24268461

Mean platelet volume, in predicting severity of mitral regurgitation and left atrial appendage thrombosis.

Ulu SM, Ozkeçeci G, Akci O, Ahsen A, Altug A, Demir K, Acartürk G.Author information aDepartment of Internal Medicine bDepartment of Cardiology, Afyon Kocatepe University, Faculty of Medicine, Afyonkarahisar, Turkey.AbstractThe incidence of thromboembolism is higher in mitral regurgitation. Mean platelet volume (MPV), which is calculated automatically in the complete blood count tests, indicates platelet production, function and activation. Elevated MPV levels in cardiovascular diseases and some heart valve diseases have been shown before. We aimed to investigate the relationship between MPV and mitral regurgitation, and to evaluate the MPV levels according to the presence of atrial fibrillation or left atrial appendage thrombus in patients with mitral regurgitation for the first time. The study included 57 patients who had undergone transthoracic and transesophageal echocardiography for the classic symptoms and diagnosed with primary (organic) mitral regurgitation. The control group was composed of 46 age, sex and BMI-matched healthy individuals who had undergone transthoracic echocardiography and obtained normal findings. Echocardiographic evaluation was performed according to the recommendations of the American Echocardiography Society. Mean MPV values in patients with mitral regurgitation were significantly higher than the control group (P < 0.001). MPV levels and the thrombus risk were correlated with the severity of the disease. When the patients with mitral regurgitation were classified according to the presence of atrial fibrillation and left atrial appendage thrombus, patients with atrial fibrillation had higher MPV levels compared to patients with normal sinus rhythm (P < 0.001). In addition, highest MPV levels were found in patients with both atrial fibrillation and thrombosis (P < 0.001). In conclusion, measurement of MPV may be considered as a quick and reliable guide in the assessment of mitral regurgitation and thrombus, without any cost or any advanced expensive technology.
Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis.Blood Coagul Fibrinolysis.2014 Mar;25(2):119-24. doi: 10.1097/MBC.0b013e328364c453.
The incidence of thromboembolism is higher in mitral regurgitation. Mean platelet volume (MPV), which is calculated automatically in the complete blood count tests, indicates platelet production, function and activation. Elevated MPV levels in cardiovascular diseases and some heart valve diseases ha
PMID 23945061

Japanese Journal

症例心室中隔心筋切除術とlow-profile生体弁による僧帽弁置換術を行った閉塞性肥大型心筋症の1例

古川貢之,阪口修平,中村栄作 [他]
胸部外科 = The Japanese journal of thoracic surgery 68(6), 449-452, 2015-06
NAID 40020490998

手術の工夫僧帽弁・大動脈弁置換術に合併した術中左室破裂

楜澤壮樹,相澤啓,高澤一平 [他]
胸部外科 = The Japanese journal of thoracic surgery 68(5), 349-352, 2015-05
NAID 40020459140

第80回東京女子医科大学学会総会シンポジウム「東京女子医大小児医療の最前線!-"なおらない"から"なおる"へ-」Part 1 (2)こどもの心臓病のカテーテル治療

杉山央
東京女子医科大学雑誌 85(2), 44-49, 2015-04-25
心臓カテーテル治療の歴史は1966年Rashikindによる完全大血管転位の乳児に心房中隔裂開術を開発したことから始まるそれ以降、動脈管開存に対するカテーテル治療を始め多くのカテーテル治療法が開発されて臨床に用いられるようになってきている。こどものカテーテル治療の特徴として、(1)カテーテル治療のみで根治性がある手技、(2)手術との組み合わせで治療をする補助的な役割を担う手技、(3)心臓術後の遺残 …
NAID 110009900091

CASE REPORT : Percutaneous mitral commissurotomy in rheumatic mitral stenosis associated with cor triatriatum

Devidutta Soumen,Narang Rajiv,Saxena Anita [他]
Cardiovascular intervention and therapeutics 30(2), 185-187, 2015-04
NAID 40020473817

Related Pictures

★リンクテーブル★

リンク元	「僧帽状」
拡張検索	「sistlic anterior motion of the mitral valve」「systolic anterior motion of the mitral valve」「mitral ring calcification」「mitral annular calcification」

「僧帽状」

Mitral valve
	Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow. (Mitral valve labeled at center right.)
	Base of ventricles exposed by removal of the atria. (Bicuspid (mitral) valve visible at bottom left.)
Details
Latin	Valva atrioventricularis sinistra,; valva mitralis
Identifiers
Gray's	p.534
MeSH	A07.541.510.507
Dorlands; /Elsevier	12843904
TA	A12.1.04.003
FMA	7235
	Anatomical terminology