Materiały źródłowe

• #1 Mitral Regurgitation – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK553135/

  Mitral regurgitation is a heart condition characterized by the incomplete closure of the mitral valve, leading to the backflow of blood from the left ventricle into the left atrium during systole. This results in a systolic murmur heard at the apex of the heart, often radiating to the left axilla. With a global prevalence of over 2%, mitral regurgitation is a common valvular abnormality with various causes, including congenital conditions, rheumatic fever, and degenerative changes in the valve. […] The underlying pathophysiologic basis for degenerative mitral regurgitation is most commonly related to myxomatous degeneration of the mitral valve, resulting in mitral valve prolapse (MVP). MVP can occur either as a primary, non-syndromic, or a secondary, syndromic process. In primary MVP, advancing age is the driving factor responsible for disease progression. Connective tissue diseases such as Marfan syndrome, Ehlers-Danlos syndrome, MASS phenotype, systemic lupus erythematosus, osteogenesis imperfecta, and pseudoxanthoma elasticum lead to secondary MVP, causing MR.

• #1 12.4 Etiology and mechanism of mitral regurgitation | 123sonography

  https://123sonography.com/ebook/etiology-and-mechanism-mitral-regurgitation

  Mitral regurgitation is classified as a structural or functional phenomenon. […] In the former the valve or subvalvular apparatus demonstrates some type of morphological abnormality while functional mitral regurgitation is a consequence of ventricular remodeling. […] Importantly, a functional component of regurgitation may also be present in structural mitral regurgitation. […] The mitral valve and its function may be affected by various diseases and conditions. […] These include aging, mitral valve prolapse, rheumatic heart disease, endocarditis, or congenital abnormalities. […] The thickness of the valve increases with age. […] The leaflets and the subvalvular apparatus „shrink” and become less pliable. […] Another common finding is annular calcification. […] The ring of the mitral valve becomes stiffer and impairs the normal physiology of the mitral valve.

• #1 :: JCVI :: Journal of Cardiovascular Imaging

  https://e-jcvi.org/DOIx.php?id=10.4250/jcvi.2019.27.e29

  In this report, we provide an overview of a new, updated echocardiographic classification of mitral regurgitation mechanisms to provide a more comprehensive and detailed assessment of mitral valve disorders. This is relevant to modern mitral valve repair techniques, with special attention to the added value of 3D-echocardiography. […] Mitral regurgitation (MR) may develop when any part of the MV apparatus becomes abnormal. Carpentier described the pathophysiologic classification of the three types of MV pathology on the basis of a functional approach that were linked to specific repair techniques. Type I involves normal leaflet motion, type II is associated with increased leaflet motion, and type III is associated with restricted leaflet motion. […] More recently, Shah and Raney proposed a modified echocardiographic classification of MR mechanisms to provide a more comprehensive and detailed assessment of MV disorders that is relevant to modern MV repair techniques.

• #1 Mitral Regurgitation – Cardiovascular Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/cardiovascular-disorders/valvular-disorders/mitral-regurgitation

  Mitral regurgitation (MR) is incompetency of the mitral valve causing flow from the left ventricle (LV) into the left atrium during ventricular systole. […] Common causes of chronic mitral regurgitation are intrinsic valve pathology (primary MR) or distortion of a normal valve by dilatation and impairment of the left ventricle and/or the mitral annulus (secondary MR). […] Secondary (functional) MR occurs when disease of the left ventricle or atrium impairs valve function. Ventricular impairment and dilation displace the papillary muscles outward, which tether the otherwise normal leaflets and prevent them from closing fully. […] An increasingly recognized mechanism of secondary mitral regurgitation is atrial functional mitral regurgitation. This is caused by annular dilatation due to chronic atrial fibrillation with an enlarged left atrium.

• #1 Mitral Regurgitation – Mitral Valve Disease – Valvular Heart Disease – Cardiovascular Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.2.9.2.

  Mitral regurgitation (MR) is a backward blood flow from the left ventricle (LV) to the left atrium (LA) due to an incomplete closure of the mitral valve leaflets. […] Primary (organic) MR is due to primary damage of the valve apparatus (leaflets, chordae tendineae, papillary muscles, or a combination of these). […] Secondary (functional) MR is due to changes in LV/LA size and function (eg, in ischemic or dilated cardiomyopathy) in the presence of structurally normal valve apparatus. […] Etiology of chronic MR: 1) Primary: Degenerative lesions (myxomatous mitral valve disease [variable extent with bileaflet involvement known as the Barlow valve], idiopathic rupture of the chordae tendineae [fibroelastic deficiency]), systemic connective tissue disorders (Marfan syndrome, Ehlers-Danlos syndrome), calcification of the mitral annulus, infective endocarditis (infectious or noninfectious eg, associated with antiphospholipid syndrome), rheumatic disease, drug mediated (ergotamines, appetite suppressants [eg, fenfluramine; currently withdrawn]), radiation mediated, congenital (eg, mitral valve clefts).

• #1 12.4 Etiology and mechanism of mitral regurgitation | 123sonography

  https://123sonography.com/ebook/etiology-and-mechanism-mitral-regurgitation

  In mitral valve prolapse the valve protrudes beyond the mitral annular plane into the left atrium. […] The term „mitral valve prolapse” in the strict sense is a functional definition. […] It may also occur when the annulus is small or squeezed – as in the presence of excessive right heart dilatation. […] Myxomatous mitral valve prolapse is characterized by an abnormal tissue composition with mucopolysaccharide accumulation, and changes in collagen and elastic fibers. […] This leads to functional impairment and affects the competence of the valve. […] The mechanism of regurgitation may vary, but the cause is usually leaflet restriction related to chordal shortening and retraction of the leaflets. […] Thus, regurgitation is more common in elderly patients with rheumatic heart disease. […] Valvular incompetence is a common consequence of endocarditis. […] The spectrum of valvular abnormalities caused by endocarditis is wide; it includes chordal rupture (flail leaflet), leaflet perforation, ruptured pseudoaneurysms, leaflet restriction, and complex mechanisms such as annular abscess cavities or valvular dehiscence.

• #1 Mitral valve incompetence: epidemiology and causes

  https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-16/Mitral-valve-incompetence-epidemiology-and-causes

  Sometimes, spontaneous rupture of MV chordae tendineae or their marked elongation will occur, and patients will develop a flail mitral leaflet. […] Rheumatic heart disease is the most serious sequela of rheumatic fever, developing to a varying degree in up to 50% of patients with rheumatic fever, leading to mitral valve regurgitation early or later in life. […] Rheumatic heart disease affects the mitral valve in up to 50% of cases and results in mitral insufficiency, mitral stenosis, or both. […] Papillary muscle rupture is another cause of acute mitral regurgitation. […] Mitral incompetence may occur as congenital malformations of the mitral valve. […] Mitral valve regurgitation may occur as a result of mitral chordal rupture, leaflet rupture (flail leaflet), leaflet perforation or interference of the vegetation mass with leaflet closure.

• #1 12.4 Etiology and mechanism of mitral regurgitation | 123sonography

  https://123sonography.com/ebook/124-etiology-and-mechanism-mitral-regurgitation

  Chordal rupture results in a flail leaflet or – more commonly – in a „partial” flail leaflet. […] However, chordal rupture may also occur in endocarditis, rheumatic heart disease, elderly patients with degenerative abnormalities of the valve, hypertrophic cardiomyopathy, and after interventional procedures. […] The degree of mitral regurgitation caused by chordal rupture depends on where and what type of chords are involved. […] Mitral regurgitation is classified as functional (or secondary) when the valve is structurally normal. […] Valvular incompetence is caused either by annular dilatation, leaflet tethering, or distortion of mitral valve geometry. […] A combination of these mechanisms is also possible. […] Annular dilatation is a consequence of left ventricular enlargement. […] The degree to which the mitral valve compensates for annular dilatation depends on the magnitude of the initial coaptation surface (length). […] The mechanism of mitral regurgitation in the presence of an inferior infarct is very likely to be one of posterior leaflet restriction.

• #1 Mitral Regurgitation – Mitral Valve Disease – Valvular Heart Disease – Cardiovascular Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.2.9.2.

  2) Secondary: Diseases of the myocardium (ischemic heart disease, nonischemic dilated cardiomyopathy, storage and infiltrative diseases [amyloidosis, eosinophilic cardiomyopathy, carcinoid syndrome, endomyocardial fibrosis]), left atrial/annular enlargement/dysfunction (atriogenic MR). […] Etiology of acute MR: 1) Primary (organic): Lesions of the valve leaflets (infective endocarditis, leaflet trauma, eg, after balloon valvotomy), rupture of the chordae tendineae (idiopathic, myxomatous degeneration, infective endocarditis, acute rheumatic fever, leaflet trauma), papillary muscle rupture (most commonly following inferior ST-segment elevation myocardial infarction [STEMI], can be partial or complete). […] 2) Secondary (functional): Acute leaflet restriction with or without reduction in closing forces (acute myocardial infarction [MI], acute LV dilation [eg, acute myocarditis]).

• #1 12.4 Etiology and mechanism of mitral regurgitation | 123sonography

  https://123sonography.com/ebook/etiology-and-mechanism-mitral-regurgitation

  Mitral regurgitation is classified as functional (or secondary) when the valve is structurally normal. […] Valvular incompetence is caused either by annular dilatation, leaflet tethering, or distortion of mitral valve geometry. […] A combination of these mechanisms is also possible. […] Annular dilatation is a consequence of left ventricular enlargement. […] The degree to which the mitral valve compensates for annular dilatation depends on the magnitude of the initial coaptation surface (length). […] The mechanism of mitral regurgitation in the presence of an inferior infarct is very likely to be one of posterior leaflet restriction. […] The most common phenomenon leading to distortion of the mitral valve is „systolic anterior motion” (SAM) of the mitral valve, which causes outflow tract obstruction in hypertrophic cardiomyopathy. […] Surgical procedures and pathologies that affect the anatomic continuity of the anterior mitral leaflet and the aortic root may also cause functional changes in the mitral valve.

• #1 Mitral Regurgitation – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK553135/

  Left ventricular dilation due to ischemic or nonischemic cardiomyopathy secondarily impairs leaflet coaptation of a structurally normal MV, resulting in secondary MR. Dysfunction and remodeling can lead to apical and lateral papillary muscle displacement, resulting in leaflet tethering, dilation, a flattening of the mitral annulus, and lower valve closing forces. […] Mitral regurgitation leads to left ventricular volume overload due to increased stroke volume, caused by increased blood volume within the left atrium and an increased preload delivered to the left ventricle during diastole. […] In chronic progressive MR, ventricular remodeling occurs, allowing maintenance of cardiac output, and an initial increase in EF is usually observed. However, the effective EF can be considerably lower depending on the regurgitant fraction. Over time, there is a positive feedback loop by which volume overload from MR causes dilation of the ventricle, widening of the mitral annulus, and diminishing coaptation of leaflets, leading to progressive worsening of the MR. […] Eventually, volume overload becomes so severe that excitation-contraction coupling of the muscle membrane becomes impaired, and wall stress-related afterload on the left ventricle leads to dilation with decreased contractility, resulting in a reduction of EF.

• #1 Functional mitral regurgitation: an overview for surgical management framework – Nappi – Journal of Thoracic Disease

  https://jtd.amegroups.org/article/view/22588/html

  Functional mitral regurgitation (FMR) results from a dysfunction of the valvular and subvalvular apparatus of the mitral valve (MV) due to displacement of one or both papillary muscles (PM) after a myocardial infarction, which leads to MV leaflet tethering and incomplete systolic MV closure. […] Given the complexity of its pathogenesis, a solution to correct the valvular and subvalvular dysfunction, along with the left ventricular (LV) geometric distortion associated with ischaemic mitral regurgitation (IMR), has not yet been elucidated. […] The development and perpetuation of FMR has been also attributed to reduced MV closing forces. […] The interplay between reduced MV closing forces, and LV and PM dyssynchrony, has been characterized by: (I) geometrical MV abnormalities in leaflet attachments and tethering that is due to a delayed regional LV mechanical activation; (II) LV dyssynchrony itself may negatively impact systolic function, which further reduces the valvular closing forces; and (III) abnormal atrioventricular relaxation during contraction cycles causes higher left atrial pressure resulting in a positive pressure gradient within the LV chamber, affecting the mechanism of MV closure.

• #1 Mitral regurgitation – Wikipedia

  https://en.wikipedia.org/wiki/Mitral_regurgitation

  Mitral regurgitation (MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease. […] The pathophysiology of MR can be broken into three phases of the disease process: the acute phase, the chronic compensated phase, and the chronic decompensated phase. […] Acute MR (as may occur due to the sudden rupture of the chordae tendinae or papillary muscle) causes a sudden volume overload of both the left atrium and the left ventricle. The left ventricle develops volume overload because with every contraction it now has to pump out not only the volume of blood that goes into the aorta (the forward cardiac output or forward stroke volume) but also the blood that regurgitates into the left atrium (the regurgitant volume). The combination of the forward stroke volume and the regurgitant volume is known as the total stroke volume of the left ventricle.

• #1 Acute Mitral Regurgitation: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/758816-overview

  Mitral regurgitation can be divided into the following three stages: acute, chronic compensated, and chronic decompensated. […] Acute mitral regurgitation classically occurs with a spontaneous chordae tendineae or papillary muscle rupture secondary to myocardial infarction. Other causes include rupture of these structures due to mitral valve prolapse, endocarditis, and trauma. In this state, a sudden volume and pressure overload occurs on an unprepared left ventricle and left atrium, with an abrupt increase in left ventricular stroke work. Increased left ventricular filling pressures, combined with the reflux of blood from the left ventricle into the left atrium during systole, results in elevated left atrial pressures. This increased pressure is transmitted to the lungs, resulting in acute pulmonary edema and dyspnea.

• #1 Mitral valve regurgitation | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/mitral-valve-regurgitation?lang=us

  Eventually, this mechanism fails, and the left ventricle can not compensate for the volume overload. This causes the stroke volume to decrease and the cardiac output to decrease. This volume overload eventually causes a drop in forward flow. This results in an increased end-systolic volume and pressure, causing pulmonary venous hypertension and heart failure. It is at this point where the ejection fraction may fall, signifying severe mitral regurgitation. […] In contrast, in acute mitral regurgitation, sudden regurgitant volume enters into a relatively normal left atrium that does not have years to develop the compliance seen in chronic mitral regurgitation. This results in a sudden increase in left atrial pressure and pulmonary venous pressures. Thus, acute pulmonary edema is a common manifestation in acute mitral regurgitation.

• #1 Mitral Regurgitation: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/155618-overview

  In chronic compensated MR, the left atrium (LA) and ventricle have sufficient time to dilate and accommodate the regurgitant volume. Thus LA pressure is often normal or only minimally elevated. Because of the left ventricular dilatation via the process of eccentric hypertrophy, TSV and FSV are maintained. Wall stress may be normal to slightly increased as the radius of the LV cavity increases but the end-diastolic LV pressure remains normal. As the LV progressively enlarges, the mitral annulus may stretch and prevent the mitral valve leaflets from coapting properly during systole, thus worsening the MR and LV dilatation. […] In the chronic decompensated phase, cardiac dysfunction has developed, impairing both TSV and FSV (although ejection fraction still may be normal). This results in a higher ESV and EDV, which in turn causes a elevation of LV and LA pressure, ultimately leading to pulmonary edema and, if left untreated, cardiogenic shock.

• #1 Acute Mitral Regurgitation: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/758816-overview

  If the patient tolerates the acute phase, the chronic compensated phase begins. The chronic compensated phase results in eccentric left ventricular hypertrophy. The combination of increased preload and hypertrophy produces increased end-diastolic volumes, which, over time, result in left ventricular muscle dysfunction. This muscle dysfunction impairs the emptying of the ventricle during systole. Therefore, regurgitant volume and left atrial pressures increase, leading to pulmonary congestion.

• #1 Mitral regurgitation – Wikipedia

  https://en.wikipedia.org/wiki/Mitral_regurgitation

  If the MR develops slowly over months to years or if the acute phase cannot be managed with medical therapy, the individual will enter the chronic compensated phase of the disease. In this phase, the left ventricle develops eccentric hypertrophy in order to better manage the larger than normal stroke volume. […] An individual may be in the compensated phase of MR for years, but will eventually develop left ventricular dysfunction, the hallmark for the chronic decompensated phase of MR. It is currently unclear what causes an individual to enter the decompensated phase of this disease. However, the decompensated phase is characterized by calcium overload within the cardiac myocytes.

• #1 Usefulness of Vasodilator Therapy in Regurgitant Valvular Diseases – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-usefulness-vasodilator-therapy-in-regurgitant-articulo-13100636

  The regurgitant volume directly depends on the regurgitant orifice, the duration of regurgitation and the pressure gradient between the cavities where regurgitation occurs. […] There are few studies on variations in the regurgitant orifice, but they seem to be associated with the presence or absence of structural valve disease and loading conditions. […] Although mitral regurgitation is more dynamic than aortic regurgitation, experimental studies have shown that the aortic regurgitant orifice area decreases during diastole and also depends on the loading conditions. […] Clearly, changes in the regurgitant orifice area are associated with the etiology of valvular regurgitation and the degree of structural changes. […] In aortic regurgitation secondary to valvular thickening or calcification, the regurgitant orifice area is relatively constant. Nevertheless, when regurgitation is due to valvular prolapse or aortic root dilatation, the regurgitant orifice area can vary considerably, depending on the loading conditions.

• #1

  https://journals.lww.com/mamc/fulltext/2015/01030/mechanisms_and_pathophysiology_of_mitral_valve.6.aspx

  In the presence of MR, during systole, LV empties into the low-pressure high compliance LA as well as into the high-pressure and high-resistance systemic circulation. The volume of regurgitation in to LA depends on the size of the regurgitant orifice, transmitral gradient (LV-LA gradient), LA size and its compliance, pulmonary vascular compliance, systemic vascular resistance, LV volume, and duration of systole. Increases in peripheral vascular resistance, LV volume, and duration of systole (bradycardia) increase the regurgitant fraction whereas decreases in all these variables decrease regurgitant fraction. Patients with mild to moderate MR may remain asymptomatic with little or no hemodynamic compromise for many years; however, MR from a primary MV abnormality tends to progress over time with an increase in volume overload due to an increase in the effective orifice area. Progression of the MR is variable and determined by the progression of lesions or mitral annulus size.

• #1

  https://journals.lww.com/mamc/fulltext/2015/01030/mechanisms_and_pathophysiology_of_mitral_valve.6.aspx

  The role of the transmitral gradient is contradictory in ischemic/dilated cardiomyopathy and in clinical situations where the regurgitant orifice is fixed due to structural disease. In situations where the regurgitant orifice is fixed, an increase in transmitral gradient increases MR. In ischemic cardiomyopathy, decrease in myocardial contractility results in LV dilation, mitral annular dilation, tethering of MV leaflets, decreased transmitral gradient, and MR. Therefore, an increase in myocardial contractility, though, increases the transmitral gradient but decreases the LV size, annulus size, and tethering effect on MV leaflets, and therefore, decreases MR. The MR results in volume overload of the LA and LV. The chronic LV volume overload in MR results in increasing annular dilatation that leads to cascading effect and further increases in MR that is why the terminology „MR begets MR.” In the early stages of chronic MR, the LV systolic and diastolic functions are usually preserved. However, during later stages, LV systolic dysfunction is almost universally present and is typically masked by its unloading into the highly compliant LA; therefore, the load-dependent measures of systolic ventricular function such as ejection fraction (EF), significantly underestimate the severity of myocardial dysfunction. Diastolic function is frequently impaired in advanced stages of MR as the LV becomes less compliant and filling pressures increase. Over a period, chronic LA-LV volume overload results in pulmonary hypertension, right ventricular hypertrophy, septal flattening, tricuspid regurgitation, systemic and pulmonary congestion, and symptoms of backward failure.

• #1 Mitral regurgitation – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/322

  Mitral regurgitation (MR) may present with dyspnea, usually on exertion, palpitations, and/or decreased exercise tolerance. […] Transthoracic echo is the diagnostic test of choice in identifying presence, severity, and mechanism of MR. […] Any aberrations of the mitral valve apparatus, due to mechanical, traumatic, infectious, degenerative, congenital, or metabolic causes, may lead to mitral regurgitation (MR). […] Mild to moderate disease can be asymptomatic for many years; however, with progression of the disease, eccentric cardiac hypertrophy occurs, which leads to elongation of the myocardial fibers and increased left ventricular end-diastolic volume. Eventually, prolonged volume overload leads to left ventricular dysfunction and increased left ventricular end-systolic diameter.

• #1 Echocardiographic evaluation of mitral valve regurgitation

  https://www.oaepublish.com/articles/2574-1225.2020.36

  In case of ventricular disease, due to either ischemic or non-ischemic cardiomyopathy, MR occurs due to regional or global remodeling of the LV, which causes lateral displacement of papillary muscles, resulting in annular dilation and leaflet tethering. However, there are some differences in the mechanism of MR in these two types of cardiomyopathy. The main mechanism for secondary MR in ischemic cardiomyopathy occurs due to inferior wall motion abnormalities, leading to systolic restriction and tethering of the posterior MV leaflet. This asymmetrical tenting pattern of the MV leaflets usually leads to posteriorly directed MR. In contrast, non-ischemic secondary MR is usually associated with global wall motion abnormalities, leading to equal displacement of papillary muscles and annular dilation, which results in symmetrical tethering of both leaflets leading to central MR.

• #1 Echocardiographic evaluation of mitral valve regurgitation

  https://www.oaepublish.com/articles/2574-1225.2020.36

  Atrial fibrillation is another common cause of secondary MR, termed atrial MR. In patients with chronic atrial fibrillation, severe LA enlargement and annular dilation can lead to incomplete coaptation of the MV leaflets. Atrial remodeling of the mitral annulus can also lead to posterior displacement of the mitral annulus and tethering of the posterior MV leaflet. In addition, myocardial dyssynchrony due to left bundle branch block or right ventricular pacing can potentially predispose to MR by a decrease in MV closing forces and dyssynchronous papillary muscle function.

• #1 Frontiers | Epidemiology, Pathophysiology, and Management of Native Atrioventricular Valve Regurgitation in Heart Failure Patients

  https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.713658/full

  Management of MR in the setting of HF depends on its underlying mechanism. In cases of primary MR leading to HF, surgical or percutaneous treatment of the mitral valve can lead to an improvement or stabilisation of HF at early stages. […] By reversing LV remodelling, medical treatment may secondarily reduce MR severity. […] The cornerstone of conventional medical treatment for HFrEF involves, on top of diuretics for acute decompensations, neurohormonal therapies targeting the inhibition of the sympathetic nervous system (beta-blockers) and the renin-angiotensin-aldosterone system (RAAi). […] Cardiac resynchronization therapy (CRT) is recommended for patients in sinus rhythm with LVEF ≤ 35%, a QRS duration ≥130 ms or ≥150 ms and LBBB morphology who remain symptomatic despite OMT in order to improve symptoms and reduce morbidity and mortality. […] Atrial fibrillation-induced left atrial and annular enlargement lead to atrial MR development or worsening, and further atrial remodelling and fibrosis that perpetuate atrial fibrillation and MR.

• #1 Mitral Regurgitation in Hypertrophic Cardiomyopathy: A Narrative Review of Mechanism and Current Management

  https://clinmedjournals.org/articles/ijcc/international-journal-of-clinical-cardiology-ijcc-9-248.php?jid=ijcc

  Significant mitral regurgitation (MR) is frequent in patients with hypertrophic cardiomyopathy (HCM) either obstructive or non-obstructive. […] Complete understanding the mechanism of MR and accurate quantification can guide towards the selection of therapeutic modality. […] SAM is initiated by rapid LV ejection through an LVOT narrowed by ventricular septal hypertrophy and anterior displacement of the MV apparatus. This result in production of drag forces, which draw both the MV leaflets and chordae towards the interventricular septum. […] Anterior displacement of the papillary muscles shifts the MV leaflets anteriorly toward the LVOT and leads to chordal and leaflet laxity. […] Significant MR due to MV abnormalities may occur in up to 10% to 20% of patients with HCM who carry a genetic mutation for HCM but have not manifested septal hypertrophy or LVOTO.

• #1 Mitral Regurgitation in Hypertrophic Cardiomyopathy: A Narrative Review of Mechanism and Current Management

  https://clinmedjournals.org/articles/ijcc/international-journal-of-clinical-cardiology-ijcc-9-248.php?jid=ijcc

  The true prevalence of mitral abnormalities in HCM is difficult to assess, as many abnormalities are poorly appreciated and often not documented. […] It is known that up to 59% of patients with HCM have at least one abnormality of the MV apparatus as a direct effect of genetic mutations. […] MV abnormalities may be present in any component of the mitral apparatus (Leaflets, subvalvular apparatus and annulus) and thus numerous abnormalities have been described with wide variability among patients with both obstructive and non-obstructive types of HCM. […] The mechanism of valve thickening and calcification is unknown, but the traumatic fibrosis from repetitive septal contact may result in retraction, and MR. […] Intrinsic MV disease is often obscured by the uniform presence of dynamic MR, but presence of MR without SAM or presence of an anteriorly directed jet is strong evidence for intrinsic MV disease.

• #1 Mitral regurgitation in the critically ill: the devil is in the detail | Annals of Intensive Care | Full Text

  https://annalsofintensivecare.springeropen.com/articles/10.1186/s13613-023-01163-4

  The dynamic nature of MR necessitates repeat assessment after therapeutic interventions or altered loading conditions. […] The presence of a flow convergence zone at the recommended Nyquist limit range of 50-70 cm/s is likely to indicate moderate or severe MR even in the absence of a significant colour jet. […] The upstream and downstream consequences of MR, including reduced cardiac output, pulmonary venous hypertension and RV dysfunction, are important to recognise and quantify in the critically ill patient.

• #1 Frontiers | Epidemiology, Pathophysiology, and Management of Native Atrioventricular Valve Regurgitation in Heart Failure Patients

  https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.713658/full

  In patients with chronic HF, progressive LV remodelling induces changes in the geometry, volume and function of the LV and papillary muscle displacement, often associated with progressive annular dilation and flattening, all contributing to the development of secondary MR. […] Overall, the mechanism of MR in chronic HF combines Carpentier types I and IIIb. […] The specificity of secondary MR in patients with HFrEF is that it is a dynamic condition, affected by changes in loading conditions, pressure or volume. […] In the absence of underlying cardiomyopathy, patients with long-standing primary MR can develop progressive HF over time. The mechanism of HF in this case is a maladaptive remodelling, which changes the geometry, volume and function of the LV and induces papillary muscle displacement.

• #1 Mitral regurgitation in the critically ill: the devil is in the detail | Annals of Intensive Care | Full Text

  https://annalsofintensivecare.springeropen.com/articles/10.1186/s13613-023-01163-4

  Mitral regurgitation (MR) is common in the critically unwell and encompasses a heterogenous group of conditions with diverging therapeutic strategies. […] Critical illness is associated with marked physiological stress and haemodynamic changes that dynamically influence the severity and implication of MR. […] Any significant mitral regurgitation requires mechanistic explanation (e.g. ruptured chordae, poor coaptation from annular dilation, etc.). […] MR may be categorised as acute versus chronic, primary versus secondary or using the Carpentier classification. […] Chronic MR should be considered in those with a history of mitral regurgitation or with risk factors such as hypertension, ischaemic heart disease, cardiomyopathy or renal failure. […] Importantly, despite progressive deterioration in LV contractile function, ejection fraction (EF) commonly remains within the normal range.

• #1 Echocardiographic evaluation of mitral valve regurgitation

  https://www.oaepublish.com/articles/2574-1225.2020.36

  Echocardiography is the primary imaging modality for the evaluation of mitral valve regurgitation. A comprehensive assessment of mitral regurgitation using different echocardiographic techniques provides important information regarding the etiology and severity of mitral regurgitation and its consequences on cardiac function. In addition, echocardiography plays an important role in the management of patients with mitral regurgitation. […] Understanding the complex anatomy of the mitral valve (MV) is essential for accurate assessment of MR. The MV apparatus consists of mitral annulus, MV leaflets, chordae tendineae, papillary muscles and the underlying ventricular wall. Pathological abnormality of any one of these components can lead to MR. For instance, MR can occur due to primary (degenerative) MV disease affecting the MV leaflets and/or chordae tendineae, while secondary MR occurs due to a pathological process of the LV or left atrium (LA).

• #1 Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging | Nature Reviews Cardiology

  https://www.nature.com/articles/s41569-019-0305-z

  Mitral regurgitation (MR) is a common valvular heart disease and is the second most frequent indication for heart valve surgery in Western countries. […] Cardiac imaging is crucial for diagnosis, identifying the cause of the disease, monitoring disease progression and planning definitive treatment for MR. […] Cardiovascular magnetic resonance imaging (CMR) has also emerged in the past 20 years as a robust, noninvasive imaging modality for the assessment of patients with MR. […] CMR offers a comprehensive evaluation of MR and its effects on the heart by providing precise volumetric assessment (using cine images) and myocardial scar or fibrosis assessment (using the late gadolinium enhancement (LGE) technique). […] CMR can provide information about the mechanism of MR by identifying morphological abnormalities of the mitral valve apparatus.

• #1 Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging | Nature Reviews Cardiology

  https://www.nature.com/articles/s41569-019-0305-z

  The presence of billowing or flail segments can be identified by dedicated cine imaging focusing on the different scallops of the mitral valve leaflets. […] In secondary MR, CMR can provide an accurate assessment of LV dilatation and (dys)function, in addition to the identification of myocardial and papillary muscle scar formation. […] CMR is an emerging, noninvasive tool that can provide comprehensive assessment of the mitral valve and MR. […] A thorough evaluation with the use of cine CMR allows a systematic inspection of the anatomy of the mitral valve and characterizes the MR, both of which contribute to determining the aetiology of the MR. […] The severity of the MR can be evaluated using several CMR-based quantitative techniques that are detailed below. […] Persistent volume overload from MR results in impaired LV function and subsequent myocardial fibrosis.

• #1 Mitral Regurgitation – Cardiovascular Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/cardiovascular-disorders/valvular-disorders/mitral-regurgitation

  Complications of chronic MR include gradual enlargement of the left atrium (LA); LV enlargement and eccentric hypertrophy, which initially compensates for regurgitant flow (preserving forward stroke volume) but eventually decompensates (reducing forward stroke volume); atrial fibrillation, which may be further complicated by thromboembolism; and infective endocarditis. […] Acute mitral regurgitation may cause acute pulmonary edema and cardiogenic shock or sudden cardiac death.

• #1 Mitral Valve Regurgitation | Cedars-Sinai

  https://www.cedars-sinai.org/health-library/diseases-and-conditions/m/mitral-valve-regurgitation.html

  Surgery may be needed with severe mitral valve regurgitation. Surgery is often needed right away for acute severe mitral valve regurgitation. The surgeon may be able to repair the mitral valve. In some cases, a replacement valve is needed. […] With mitral valve regurgitation, the hearts mitral valve is leaky. Some blood flows back into the left atrium from the left ventricle.

• #1

  https://link.springer.com/article/10.1007/s11748-021-01629-x

  Mitral annular plication (MAP) with an artificial ring is an essential surgical procedure because dilatation of the mitral valve annulus is a main factor underlying this pathology. […] We consider that the left atrial plication procedure around the mitral valve annulus should be performed simultaneously and the left atrial appendage must be closed. […] The pathology of atrial functional MR is completely different from that of conventional ventricular functional MR.

• #2

  https://journals.lww.com/mamc/fulltext/2015/01030/mechanisms_and_pathophysiology_of_mitral_valve.6.aspx

  The mitral valve (MV) is a sophisticated natural engineering marvel. The MV requires coordinated action of all its interrelated anatomical components: The MV leaflets, the annulus, the left atrium, the tendinous chords and the papillary muscles with its surrounding left ventricular wall for an effective closure of its orifice. Mitral valve regurgitation (MR) is frequently found in patients undergoing cardiac surgery with cardiopulmonary bypass. MR can be secondary to a structural or a functional defect of one or several components of the MV. The mechanism(s) of functional MR is the most complex. A precise understanding of the pathophysiology of MR helps resolving the cardiac status of a patient and choice of therapy for a particular patient. Transesophageal echocardiography can define the underlying mechanism(s) of MR; a thorough understanding of the mechanism(s) helps deciding the surgical procedure needed to repair the MR.

• #2 Basic Mechanisms of Mitral Regurgitation

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4281524/

  Any structural or functional impairment of the mitral valve (MV) apparatus that exhausts MV tissue redundancy available for leaflet coaptation will result in mitral regurgitation (MR). The mechanism responsible for MV malcoaptation and MR can be dysfunction or structural change of the left ventricle, the papillary muscles, the chordae tendineae, the mitral annulus and the MV leaflets. […] Significant MR regardless of etiology can prompt independent and ongoing LV and MV apparatus remodeling and start a vicious circle whereby reactive remodeling contributes to MR. An example is MA dilatation and dysfunction, which is rarely a primary cause for MR, but much more commonly a consequence of other MV or LV diseases. […] MR develops if the MV leaflets do not sufficiently cover the MA orifice throughout LV systole, and is commonly classified as primary MR – indicating leaflet pathology – or secondary MR in the setting of LV myocardial pathology.

• #2 :: JCVI :: Journal of Cardiovascular Imaging

  https://e-jcvi.org/DOIx.php?id=10.4250/jcvi.2019.27.e29

  The presence, location, and extent of prolapse are of crucial importance in defining the likelihood of successful MV repair. […] Accurate description of the MR mechanism is crucial for determination of the need for and type of MV surgery. Addition of 3D echocardiography may be particularly helpful in identification of MV leaflet perforation, cleft, or prolapse and a more reproducible definition of MV annulus dilatation. The described modified classification by Shah and Raney provides a more comprehensive and detailed assessment of MV disorders. Further studies should investigate whether this modified classification has an impact on surgical techniques and outcome.

• #2 Pathophysiology and natural history of chronic mitral regurgitation – UpToDate

  https://www.uptodate.com/contents/pathophysiology-and-natural-history-of-chronic-mitral-regurgitation

  Chronic mitral regurgitation (MR) is a relatively common valvular disorder that can progress to ventricular decompensation and the need for mitral valve surgery. […] Mitral regurgitation (MR) may be due to a primary abnormality (sometimes referred to as organic MR) of one or more of the four components of the valve apparatus (leaflets, chordae tendineae, papillary muscles, and annulus) or the MR may be secondary (often referred to as functional MR) to left ventricular (LV) dilation and dysfunction (such as coronary heart disease or a cardiomyopathy). […] Several disease processes cause abnormalities of the mitral valve complex leading to primary MR. […] In mitral valve prolapse, what appears to be excessive mitral leaflet tissue and excessive surface area leads to redundancy, folding, and hooding affecting one or more segments of one or both leaflets. Chordae are elongated and may eventually rupture (with flail or partial flail), and the annulus is typically dilated and frequently disjuncted from its normal myocardial support. The alterations yield inadequate apposition of the rough zones of the mitral leaflets so they no longer support each other during systole and fall into the left atrium.

• #2 12.4 Etiology and mechanism of mitral regurgitation | 123sonography

  https://123sonography.com/ebook/124-etiology-and-mechanism-mitral-regurgitation

  In mitral valve prolapse the valve protrudes beyond the mitral annular plane into the left atrium. […] The term „mitral valve prolapse” in the strict sense is a functional definition. […] It may also occur when the annulus is small or squeezed – as in the presence of excessive right heart dilatation. […] Myxomatous mitral valve prolapse is characterized by an abnormal tissue composition with mucopolysaccharide accumulation, and changes in collagen and elastic fibers. […] This leads to functional impairment and affects the competence of the valve. […] The mechanism of regurgitation may vary, but the cause is usually leaflet restriction related to chordal shortening and retraction of the leaflets. […] Thus, regurgitation is more common in elderly patients with rheumatic heart disease. […] Valvular incompetence is a common consequence of endocarditis. […] The spectrum of valvular abnormalities caused by endocarditis is wide; it includes chordal rupture (flail leaflet), leaflet perforation, ruptured pseudoaneurysms, leaflet restriction, and complex mechanisms such as annular abscess cavities or valvular dehiscence.

• #2 Mitral valve incompetence: epidemiology and causes

  https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-16/Mitral-valve-incompetence-epidemiology-and-causes

  Sometimes, spontaneous rupture of MV chordae tendineae or their marked elongation will occur, and patients will develop a flail mitral leaflet. […] Rheumatic heart disease is the most serious sequela of rheumatic fever, developing to a varying degree in up to 50% of patients with rheumatic fever, leading to mitral valve regurgitation early or later in life. […] Rheumatic heart disease affects the mitral valve in up to 50% of cases and results in mitral insufficiency, mitral stenosis, or both. […] Papillary muscle rupture is another cause of acute mitral regurgitation. […] Mitral incompetence may occur as congenital malformations of the mitral valve. […] Mitral valve regurgitation may occur as a result of mitral chordal rupture, leaflet rupture (flail leaflet), leaflet perforation or interference of the vegetation mass with leaflet closure.

• #2 Functional mitral regurgitation: an overview for surgical management framework – Nappi – Journal of Thoracic Disease

  https://jtd.amegroups.org/article/view/22588/html

  In the symmetrical type there is a combination of apical and medio-lateral vectorial tethering, as well as a more displaced coaptation point. […] The extent of LV remodeling is also affected by the direction and severity of vector displacement of the PMs, regional LV dysfunction, and the degree of PM dyssynchrony. […] The evidence supporting the role of closing forces in FMR includes the following observations: a reduction of LV contractility and global LV dyssynchrony is prevalent in patients with less than severe FMR, altered mitral annular systolic contraction is observed in patients with moderate leaflet tethering, and PM dyssynchrony persists in patients who received restrictive annuloplasty MV repair.

• #2

  https://link.springer.com/article/10.1007/s11748-021-01629-x

  Atrial functional mitral regurgitation is a hot research topic in the field of mitral valve disease. Atrial functional mitral regurgitation is distinctly different from ventricular functional mitral regurgitation. The surgical indications for atrial functional mitral regurgitation have not been well established because of the small amount of evidence gathered to date. Mitral annular plication with an artificial ring is an essential surgical procedure because dilatation of the mitral valve annulus is a main factor underlying this pathology. […] Chronic atrial fibrillation causes enlargement of the right and left atria. This pathology is a bilateral atrioventricular valve disease (dual-valve disease). Therefore, the conventional guidelines of single-valve disease should not be applied. […] The mechanism of MR is distinctly different from so-called functional regurgitation (ventricular functional MR).

• #2 Mitral valve regurgitation | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/mitral-valve-regurgitation?lang=us

  Eventually, this mechanism fails, and the left ventricle can not compensate for the volume overload. This causes the stroke volume to decrease and the cardiac output to decrease. This volume overload eventually causes a drop in forward flow. This results in an increased end-systolic volume and pressure, causing pulmonary venous hypertension and heart failure. It is at this point where the ejection fraction may fall, signifying severe mitral regurgitation. […] In contrast, in acute mitral regurgitation, sudden regurgitant volume enters into a relatively normal left atrium that does not have years to develop the compliance seen in chronic mitral regurgitation. This results in a sudden increase in left atrial pressure and pulmonary venous pressures. Thus, acute pulmonary edema is a common manifestation in acute mitral regurgitation.

• #2 Usefulness of Vasodilator Therapy in Regurgitant Valvular Diseases – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-usefulness-vasodilator-therapy-in-regurgitant-articulo-13100636

  Mitral and aortic valve regurgitation both lead to left ventricle volume overload, but have different pathophysiology. Preload is increased in mitral regurgitation whereas afterload is normal since part of the ejection flow goes to the left atrium; however, both pre- and afterload are increased in aortic regurgitation. […] When the regurgitations are chronic, the ventricle adapts by increasing the volumes and causing eccentric left ventricular hypertrophy. Nevertheless, when the adaptation mechanisms fail, in the long term left ventricular filling pressures increase and, finally, the ejection fraction decreases, leading to signs and symptoms of heart failure. […] In acute regurgitations these adaptation mechanisms may not be sufficiently rapid, and although the left ventricle responds with greater hypercontractility, the acute increase in preload can increase filling pressures and trigger pulmonary edema.

• #2 Mitral regurgitation – Wikipedia

  https://en.wikipedia.org/wiki/Mitral_regurgitation

  If the MR develops slowly over months to years or if the acute phase cannot be managed with medical therapy, the individual will enter the chronic compensated phase of the disease. In this phase, the left ventricle develops eccentric hypertrophy in order to better manage the larger than normal stroke volume. […] An individual may be in the compensated phase of MR for years, but will eventually develop left ventricular dysfunction, the hallmark for the chronic decompensated phase of MR. It is currently unclear what causes an individual to enter the decompensated phase of this disease. However, the decompensated phase is characterized by calcium overload within the cardiac myocytes.

• #2 Usefulness of Vasodilator Therapy in Regurgitant Valvular Diseases – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-usefulness-vasodilator-therapy-in-regurgitant-articulo-13100636

  The regurgitant volume directly depends on the regurgitant orifice, the duration of regurgitation and the pressure gradient between the cavities where regurgitation occurs. […] There are few studies on variations in the regurgitant orifice, but they seem to be associated with the presence or absence of structural valve disease and loading conditions. […] Although mitral regurgitation is more dynamic than aortic regurgitation, experimental studies have shown that the aortic regurgitant orifice area decreases during diastole and also depends on the loading conditions. […] Clearly, changes in the regurgitant orifice area are associated with the etiology of valvular regurgitation and the degree of structural changes. […] In aortic regurgitation secondary to valvular thickening or calcification, the regurgitant orifice area is relatively constant. Nevertheless, when regurgitation is due to valvular prolapse or aortic root dilatation, the regurgitant orifice area can vary considerably, depending on the loading conditions.

• #2 Mitral Regurgitation – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK553135/

  Left ventricular dilation due to ischemic or nonischemic cardiomyopathy secondarily impairs leaflet coaptation of a structurally normal MV, resulting in secondary MR. Dysfunction and remodeling can lead to apical and lateral papillary muscle displacement, resulting in leaflet tethering, dilation, a flattening of the mitral annulus, and lower valve closing forces. […] Mitral regurgitation leads to left ventricular volume overload due to increased stroke volume, caused by increased blood volume within the left atrium and an increased preload delivered to the left ventricle during diastole. […] In chronic progressive MR, ventricular remodeling occurs, allowing maintenance of cardiac output, and an initial increase in EF is usually observed. However, the effective EF can be considerably lower depending on the regurgitant fraction. Over time, there is a positive feedback loop by which volume overload from MR causes dilation of the ventricle, widening of the mitral annulus, and diminishing coaptation of leaflets, leading to progressive worsening of the MR. […] Eventually, volume overload becomes so severe that excitation-contraction coupling of the muscle membrane becomes impaired, and wall stress-related afterload on the left ventricle leads to dilation with decreased contractility, resulting in a reduction of EF.

• #2 Echocardiographic evaluation of mitral valve regurgitation

  https://www.oaepublish.com/articles/2574-1225.2020.36

  In case of ventricular disease, due to either ischemic or non-ischemic cardiomyopathy, MR occurs due to regional or global remodeling of the LV, which causes lateral displacement of papillary muscles, resulting in annular dilation and leaflet tethering. However, there are some differences in the mechanism of MR in these two types of cardiomyopathy. The main mechanism for secondary MR in ischemic cardiomyopathy occurs due to inferior wall motion abnormalities, leading to systolic restriction and tethering of the posterior MV leaflet. This asymmetrical tenting pattern of the MV leaflets usually leads to posteriorly directed MR. In contrast, non-ischemic secondary MR is usually associated with global wall motion abnormalities, leading to equal displacement of papillary muscles and annular dilation, which results in symmetrical tethering of both leaflets leading to central MR.

• #2 Mitral Regurgitation in Hypertrophic Cardiomyopathy: A Narrative Review of Mechanism and Current Management

  https://clinmedjournals.org/articles/ijcc/international-journal-of-clinical-cardiology-ijcc-9-248.php?jid=ijcc

  Significant mitral regurgitation (MR) is frequent in patients with hypertrophic cardiomyopathy (HCM) either obstructive or non-obstructive. […] Complete understanding the mechanism of MR and accurate quantification can guide towards the selection of therapeutic modality. […] SAM is initiated by rapid LV ejection through an LVOT narrowed by ventricular septal hypertrophy and anterior displacement of the MV apparatus. This result in production of drag forces, which draw both the MV leaflets and chordae towards the interventricular septum. […] Anterior displacement of the papillary muscles shifts the MV leaflets anteriorly toward the LVOT and leads to chordal and leaflet laxity. […] Significant MR due to MV abnormalities may occur in up to 10% to 20% of patients with HCM who carry a genetic mutation for HCM but have not manifested septal hypertrophy or LVOTO.

• #2 Mitral Regurgitation in Hypertrophic Cardiomyopathy: A Narrative Review of Mechanism and Current Management

  https://clinmedjournals.org/articles/ijcc/international-journal-of-clinical-cardiology-ijcc-9-248.php?jid=ijcc

  The true prevalence of mitral abnormalities in HCM is difficult to assess, as many abnormalities are poorly appreciated and often not documented. […] It is known that up to 59% of patients with HCM have at least one abnormality of the MV apparatus as a direct effect of genetic mutations. […] MV abnormalities may be present in any component of the mitral apparatus (Leaflets, subvalvular apparatus and annulus) and thus numerous abnormalities have been described with wide variability among patients with both obstructive and non-obstructive types of HCM. […] The mechanism of valve thickening and calcification is unknown, but the traumatic fibrosis from repetitive septal contact may result in retraction, and MR. […] Intrinsic MV disease is often obscured by the uniform presence of dynamic MR, but presence of MR without SAM or presence of an anteriorly directed jet is strong evidence for intrinsic MV disease.

• #2 Mitral Regurgitation – Cardiovascular Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/cardiovascular-disorders/valvular-disorders/mitral-regurgitation

  Complications of chronic MR include gradual enlargement of the left atrium (LA); LV enlargement and eccentric hypertrophy, which initially compensates for regurgitant flow (preserving forward stroke volume) but eventually decompensates (reducing forward stroke volume); atrial fibrillation, which may be further complicated by thromboembolism; and infective endocarditis. […] Acute mitral regurgitation may cause acute pulmonary edema and cardiogenic shock or sudden cardiac death.

• #2 Frontiers | Epidemiology, Pathophysiology, and Management of Native Atrioventricular Valve Regurgitation in Heart Failure Patients

  https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.713658/full

  Management of MR in the setting of HF depends on its underlying mechanism. In cases of primary MR leading to HF, surgical or percutaneous treatment of the mitral valve can lead to an improvement or stabilisation of HF at early stages. […] By reversing LV remodelling, medical treatment may secondarily reduce MR severity. […] The cornerstone of conventional medical treatment for HFrEF involves, on top of diuretics for acute decompensations, neurohormonal therapies targeting the inhibition of the sympathetic nervous system (beta-blockers) and the renin-angiotensin-aldosterone system (RAAi). […] Cardiac resynchronization therapy (CRT) is recommended for patients in sinus rhythm with LVEF ≤ 35%, a QRS duration ≥130 ms or ≥150 ms and LBBB morphology who remain symptomatic despite OMT in order to improve symptoms and reduce morbidity and mortality. […] Atrial fibrillation-induced left atrial and annular enlargement lead to atrial MR development or worsening, and further atrial remodelling and fibrosis that perpetuate atrial fibrillation and MR.

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