Papillary Muscle Displacement Research Articles

Race, gender and clinical presentation in apical hypertrophic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background The apical variant of hypertrophic cardiomyopathy (ApHCM) has male predominance and is a relatively rare phenotype in Western population. Characteristics of female and black patients diagnosed with ApHCM are very limited in the existing literature. Purpose We aimed to investigate whether gender and race are associated with a different clinical presentation and CMR findings in apical HCM. Methods We retrospectively analysed 150 patients (113 males and 37 females) with a diagnosis of apical HCM who have been followed in our inherited cardiac conditions (ICC) clinic between 2010 and 2020. Only patients with a CMR study and apical hypertrophy defined as ≥ 13mm at the time of diagnosis were included. Demographics and clinical characteristics were obtained from electronic records. Volumetric CMR data were taken from confirmed reports while other parameters were measured by standard protocol. "Pure" ApHCM was defined as isolated apical hypertrophy and "mixed" with both apical and septal hypertrophy but with the apex thickest (1). Apical displacement of papillary muscles (PM) was defined when the base of PM originated from the apical one-third of the left ventricle (LV) in the apical 4- or 2-chamber views. Giant T-wave inversion was defined as T-wave inversion that is equal or greater than 10 mm (1 mV) in any electrocardiogram lead. Results Our study population included patients of White (55, 37%), Black (37, 25%), Asian (36, 24%) and Mixed/Others (22, 15%) ethnicity. Black patients were more likely to have a diagnosis of hypertension at presentation when compared to White (70% vs 40%, p = 0.01) and to Asian and Mixed/Other patients (70% vs 48%, p = 0.03). Similarly, they were more likely to have "mixed" ApHCM than White (49% vs 20%, p = 0.003) and Asian and Mixed/Other (49% vs 26%, p = 0.02) patients. Females were diagnosed at an older age (63 ± 12 vs 52 ± 14, p < 0.001) and were less likely to have deep T-wave inversion on their ECG at presentation (14% vs 32%, p = 0.03) compared to their male counterparts. Females in this cohort also had higher representation of black ethnicity and were more likely to have hypertension (68% vs 47%, p = 0.03). Apart from the expected gender related differences in volumes and LV mass, there were no differences in cardiomyopathy-specific parameters we investigated. Conclusions In our cohort, females with ApHCM presented at an older age and were less likely to have giant T-wave inversion on ECG. Black patients with ApHCM were more likely to have hypertension and the "mixed" type of the disease.

STUDY OF CORRELATION BETWEEN SEVERITY OF ISCHEMIC MITRAL VALVE REGURGITATION BY ECHO DOPPLER AND ECG CHANGES IN ACUTE MYOCARDIAL INFARCTION

Background: Myocardial infarction (MI) accompanies with different mechanical complications including ischemic mitral regurgitation (IMR) which is correlated with increased risk of mortality and heart failure. IMR existence and its severity had significant prognostic effect on patients’ mortality following acute myocardial infarction (AMI). Echocardiography is the choice imaging modality for the diagnosis and assessment of IMR and establishing its etiology. IMR usually results from papillary muscle displacement, ventricular dilation and remodeling with reduced closing forces. Objective: Assessment of the correlation between echocardiographic severity of ischemic mitral valve regurgitation following acute myocardial infarction and its electrocardiographic location. Patients and methods: This was a prospective study that included 100 patients admitted to CCU OF Beni-Suief General Hospital in the period from October 2019 to May 2020 . Those patients were divided on two equal groups: Group I: patients with STEMI and no, trivial or mild MR and Group II: patients with STEMI and moderate or severe MR. Results: Mean age of group I involved in the study was 55.44 ± 7.23 years and 70% of them were males. Mean age of group II was 58.38 ± 7.8 and 56% were males. 70 % of the group II had inferolateral STEMI compared to group I who had more anterior STEMI. Group II were more smokers with hyperlipidemia. Group II was with higher previous stable and unstable angina, with less streptokinase treatment, with higher abnormal chest radiogrgh and higher killip class. Group II had significantly lower EF and higher LVEDD, LVESD, LA diameter, RV diameter, MV A velocity, tricuspid valve excursion TAPSI and pulmonary artery pressure and more diastolic dysfunction. Mechanism of IMR in case group was mono leaflet tethering in 43 cases, both leaflet tethering in 7 cases and ring dilation in 30 cases. MR jet direction was medial commissure posterior in 31 (62%), lateral commissure anterior in 12 (24%), and both commissures central in 7 (14%) cases. Conclusion: Mitral regurgitation is common after acute myocardial infarction, especially in cases with inferior mitral regurgitation. The echocardiographic findings are indicative of left ventricular remodeling and abnormality of mitral valve apparatus.

Assessment of mitral valve function in children and young adults with hypertrophic cardiomyopathy using three-dimensional echocardiography

ObjectiveThe objective of this study was to assess papillary muscle (PM) and mitral valve (MV) structure and function in children and young adults with mild and moderate hypertrophic cardiomyopathy (HCM) using real-time three-dimensional echocardiography (3DE) and to correlate them with HCM related adverse outcomes. MethodsTransthoracic research 3DE was performed in HCM patients and controls matched for age and gender. Anterolateral and posteromedial PM mass, apical displacement of anterolateral PM, and left ventricular (LV) mass were measured and indexed to body surface area. The MV annulus and leaflet structure and function were analyzed. Individual PMs were manually planimetered by tracing the endocardial borders on each mid systole frame, taking care to distinguish PMs as distinct from the LV wall. Apical PM displacement was expressed as ratio of the distance between the apex and the base of the anterolateral PM to the entire length of the LV lateral wall (APL index). All 3DE measurements were correlated to adverse outcomes. ResultsForty subjects were studied, including 20 HCM patients (age 18.1 ± 9.6 years, 16 male and 4 female), and 20 controls (18.2 ± 9.6 years, 16 male and 4 female). The indexed LV mass in HCM was 74.8 ± 25.8 g/m2 compared to 50.8 ± 12.4 g/m2 in controls (p = 0.001). The anterolateral, posteromedial and combined PM mass were 3.1 ± 2.2 g/m2, 1.7 ± 1.2 g/m2 and 4.9 ± 2.7 g/m2 in HCM, in contrast to respective measurements of 1.1 ± 0.6 g/m2, 1.2 ± 0.6 g/m2 and 2.3 ± 0.8 g/m2 in controls (p < 0.001, p = 0.062, and p < 0.001, respectively). The mitral valve annular parameters (annulus circumference, height and area) in HCM were not significantly different from controls. The APL index in HCM was less than in controls (0.44 ± 0.07 vs. 0.55 ± 0.04, p < 0.001). The LV lateral wall length and LV mass correlated with adverse HCM outcomes, while the APL index and PM total mass were not associated with adverse events. ConclusionIt is feasible to evaluate PM muscles and MV annulus geometry in children and young adults with HCM using 3DE. The morphologic and functional changes of anterolateral PM may occur in the absence of MV annulus changes. Prospective validation will be required to determine if LV lateral wall length and LV mass may be used as predictors of adverse events.

Mitral valve cleft gapping mechanism in functional mitral regurgitation: An in-vitro study

Background and aimGapping formation of the mitral valve cleft is unknown. The objective of this study was to quantify the geometry of mitral valve cleft coaptation in the asymmetric and symmetric papillary muscles (PMs) positions in a dilated annulus in order to reveal mitral valve gapping mechanism. MethodsNine fresh porcine mitral valves with the posterior leaflet clefts were sutured onto a saddle-shaped dilated annulus in an in-vitro experiment to simulate mitral valve closure at hydrostatic pressure. PMs were adjusted to the normal position, and subsequently to positions of asymmetric and symmetric PM displacement. Sonomicrometry was used to measure positions of the lateral and medial clefts. ResultsPM displacement tethered the leaflets. Both the opening angle and contact angle of the lateral cleft, but not of the medial cleft, increased in the asymmetric PM displacement. Neither the opening angle nor contact angle of both clefts increased in the symmetric PM displacement. ConclusionsDisplacement of the postero-medial PM moves the posterior leaflet medially and impairs coaptation of the lateral cleft, but not medial cleft, which suggest that the medial cleft displacement in the asymmetric PM position is another mechanism of gap formation in addition to leaflet tenting due to apical leaflet displacement. Symmetric PM displacement cause leaflet tenting, but doesn’t impair the leaflet cleft coaptation, which suggest that the asymmetric PM position is even worse than the symmetric PM position.

Hybrid transcatheter left ventricular reconstruction for the treatment of ischemic cardiomyopathy.

Left ventricular (LV) enlargement is a mechanical adaptation to accommodate LV systolic inefficiency following an acute damage or a progressive functional deterioration, which fails to correct the decline of stroke volume in the long term, leading to progressive heart failure (HF). Surgical ventricular reconstruction (SVR) is a treatment for patients with severe ischemic HF aiming to restore LV efficiency by volume reduction and LV re-shaping. Recently, a new minimally-invasive hybrid technique for ventricular reconstruction has been developed by means of the Revivent™ system (BioVentrix Inc., San Ramon, CA, USA). The device for ventricular reconstruction consists of anchor pairs that enable plication of the anterior and free wall LV scar against the right ventricular (RV) septal scar of anteroseptal infarctions to decrease cardiac volume without ventriculotomy in a beating-heart minimally-invasive procedure, consisting of a transjugular and left thoracotomy approach. Patients with severe (Grade 4) functional mitral regurgitation (FMR) or with previous cardiac surgery procedures were excluded. Outcome of the reconstruction procedure: from 2012 until 2019, it has been applied to 203 patients, with 5 (2.5%) in-hospital deaths. LV volume reduction varied according to experience gained along years: LV end-systolic volume index decreased from baseline 43% (post-market registry) vs. 27% (CE-mark study); left ventricular ejection fraction (LVEF) increased from baseline 25% (post-market registry) vs. 16% (CE-mark study). Clinical status (NYHA class, HF questionnaire, 6-minute walking test) improved significantly compared to baseline, and re-hospitalization rate was only 13% at 6-month follow-up (60% of patients in NYHA =3). FMR grade decreased at follow-up in 63%, while it was unchanged in 37% of patients. The hybrid ventricular reconstruction (HVR) seems a promising treatment for HF patients who may benefit from LV volume reduction, with reasonable mortality and good results at follow-up. A baseline less severe clinical profile was not associated to better outcome at follow-up, which makes the procedure feasible in patients with very large ventricles and depressed ejection fraction (EF). LV reshaping has no detrimental effect on FMR, that may, on the contrary, benefit owing to less papillary muscle displacement, partial recovery of torsion dynamics and of myofibers re-orientation. A controlled study on top of optimal medical treatment is warranted to confirm its role in the management of HF patients.

Differential diagnosis of apical hypertrophic cardiomyopathy and apical displacement of the papillary muscles: a multimodality imaging point of view.

Apical hypertrophic cardiomyopathy (ApHCM) and apical displacement of papillary muscles (ADPM) are two different pathologies with a number of similar imaging findings that may hamper adequate diagnosis. While ApHCM is associated with increased rate of mortality, ADPM commonly presents with a benign course and differential diagnosis is of great importance. Clinical assessment and 2D echocardiography cannot sufficiently differentiate these conditions, however, and advanced echocardiographic methods may facilitate diagnosis. Although echocardiography is the first-line imaging method in the diagnostic algorithm, cardiac magnetic resonance imaging (CMRI) is the gold standard for evaluating patients due to good spatial resolution and myocardial tissue characterization abilities. When CMRI is contraindicated, cardiac computed tomography may be an alternative reliable method that can also give information about the coronary anatomy. Nuclear imaging may also provide supplementary data regarding hypertrophy and coronary arteries when there is a suspicion of ischemia.

Reconstructive operations on subvalvular structures of the mitral valve during remodelling of the left ventricle. Papillary muscle interventions

The optimal treatment strategy for secondary mitral regurgitation of type IIIb (A. Carpentier classification) remains debatable. The use of a standard surgical technique for treating secondary mitral regurgitation and undersized ring annuloplasty demonstrates suboptimal results in several patients (about 30% of the patients exhibit postoperative hemodynamically significant mitral regurgitation with the absence of effective reverse remodelling of the left ventricle). Such suboptimal results are associated with the unification of only the mitral valve reconstruction technique, irrespective of the state of the left ventricle (degree of dysfunction, dilatation, tethering/tenting, and papillary muscle displacement); this is not entirely justified because of the disease complexity (valve and ventricular), and it is crucial to influence both the components of the disease. Particularly, modern researchers are inclined toward the need of using additional reconstructive interventions on the subvalvular structures that contribute to a more effective reverse remodelling of the left ventricle.Here, we present a review of recent studies on the surgical treatment of functional mitral insufficiency of type IIIb (A. Carpentier classification) with effects on the subvalvular structures (pupillary muscle relocation and approximation).Revised 19 April 2020. Revised 5 May 2020. Accepted 28 May 2020.Funding: The study did not have sponsorship.Conflict of interest: Authors declare no conflict of interest.

Effect of Edge-to-Edge Mitral Valve Repair on Chordal Strain: Fluid-Structure Interaction Simulations.

Edge-to-edge repair for mitral valve regurgitation is being increasingly performed in high-surgical risk patients using minimally invasive mitral clipping devices. Known procedural complications include chordal rupture and mitral leaflet perforation. Hence, it is important to quantitatively evaluate the effect of edge-to-edge repair on chordal integrity. in this study, we employ a computational mitral valve model to simulate functional mitral regurgitation (FMR) by creating papillary muscle displacement. Edge-to-edge repair is then modeled by simulated coaptation of the mid portion of the mitral leaflets. in the setting of simulated FMR, edge-to-edge repair was shown to sustain low regurgitant orifice area, until a two fold increase in the inter-papillary muscle distance as compared to the normal mitral valve. Strain in the chordae was evaluated near the papillary muscles and the leaflets. Following edge-to-edge repair, strain near the papillary muscles did not significantly change relative to the unrepaired valve, while strain near the leaflets increased significantly relative to the unrepaired valve. These data demonstrate the potential for computational simulations to aid in the pre-procedural evaluation of possible complications such as chordal rupture and leaflet perforation following percutaneous edge-to-edge repair.

A pilot in silico modeling-based study of the pathological effects on the biomechanical function of tricuspid valves.

Current clinical assessment of functional tricuspid valve regurgitation relies on metrics quantified from medical imaging modalities. Although these clinical methodologies are generally successful, the lack of detailed information about the mechanical environment of the valve presents inherent challenges for assessing tricuspid valve regurgitation. In the present study, we have developed a finite element-based in silico model of one porcine tricuspid valve (TV) geometry to investigate how various pathological conditions affect the overall biomechanical function of the TV. There were three primary observations from our results. Firstly, the results of the papillary muscle (PM) displacement study scenario indicated more pronounced changes in the TV biomechanical function. Secondly, compared to uniform annulus dilation, nonuniform dilation scenario induced more evident changes in the von Mises stresses (83.8-125.3 kPa vs 65.1-84.0 kPa) and the Green-Lagrange strains (0.52-0.58 vs 0.47-0.53) for the three TV leaflets. Finally, results from the pulmonary hypertension study scenario showed opposite trends compared to the PM displacement and annulus dilation scenarios. Furthermore, various chordae rupture scenarios were simulated, and the results showed that the chordae tendineae attached to the TV anterior and septal leaflets may be more critical to proper TV function. This in silico modeling-based study has provided a deeper insight into the tricuspid valve pathologies that may be useful, with moderate extensions, for guiding clinical decisions. NOVELTY STATEMENT: The novelties of the research are summarized below: A comprehensive in silico pilot study of how isolated functional tricuspid regurgitation pathologies and ruptured chordae tendineae would alter the tricuspid valve function; An extensive analysis of the tricuspid valve function, including mechanical quantities (eg, the von Mises stress and the Green-Lagrange strain) and clinically-relevant geometry metrics (eg, the tenting area and the coaptation height); and A developed computational modeling pipeline that can be extended to evaluate patient-specific tricuspid valve geometries and enhance the current clinical diagnosis and treatment of tricuspid regurgitation.

Mechanisms and predictors of ischemic mitral regurgitation at rest and on exertion in patients at early stage of myocardial infarction

Aim. Determination of the mechanisms and predictors of ischemic mitral regurgitation (IMR) at rest and on exertion in patients at early stage of myocardial infarction (MI).Material and methods. Seventy-seven patients with inferoposterior MI and 79 patients with anteroseptal apical MI were examined on the 7th day at rest and after exertion. We determined the degree of IMR (according to the PISA method), posteromedial and anterolateral papillary muscle (PM) displacement, closure height of the mitral valve (MV), systolic and diastolic mitral valve orifice area, volume of the left ventricle (LV), LV contractility index, deformation of the infarction regions, general LV deformation, deformation and systolic dyssinchrony of the PM.Results. IMR was more common in inferior MI (42% vs 28%). LV volumes in cases with anteroseptal apical MI and IMR were greater and LV deformation was less than in patients without IMR. In inferoposterior MI and IMR, differences were observed in the index of local contractility and function of the posteromedial PM. The differences in MI of both localizations and IMR compared with MI without IMR were the areas of the mitral orifice and dyssinchrony of the PM. The degree of IMR after exertion did not depend on the degree of IMR at rest. Predictors of IMR at rest in MI of both localizations were the apical displacement of MV closure and the area of the mitral orifice. In inferoposterior, posteromedial PM displacement, deformation of the infarcted areas, PM dyssinchrony were also predictors. In anteroseptal apical MI, the area of the mitral orifice was the predictor of IMR. Predictors of anteroseptal apical MI after physical exertion after inferior MI were mitral orifice areas, contractility index, displacement and deformation of the posteromedial PM. In anteroseptal apical MI, the IMR predictors were MV closure height and systolic area of mitral orifice.Conclusion. The study confirms the significance of changing the spatial orientation of the MV structures in MI of both localizations, impaired regional contractility in inferoposterior MI and LV volume in anteroseptal apical MI at early stage of the disease.

Long-term ischemic mitral regurgitation: which parameters predict decrease or increase in the degree after five years?

Ischemic mitral regurgitation (IMR) is a frequent valvular heart disease and is related to worse prognosis. The aim of this study was to investigate the dynamics in the degree of IMR from the acute phase of inferoposterior myocardial infarction (MI) to 5-years follow-up and to identify the predictors of change in the degree of mitral regurgitation (MR). We included patients with first ever acute inferoposterior MI and examined them in two phases: at the time of acute MI then 5 years later. Based on two-dimensional transthoracic echocardiography, the patients were divided into the non-significant MR (NMR) group and IMR group. The parameters of left ventricle (LV), mitral apparatus and clinical data were assessed in both phases. The predictors of a decrease or an increase in the degree of mitral regurgitation after 5 years were identified. The values of the parameters of mitral apparatus and LV chambers increased with higher degrees of IMR. The tenting height, systolic blood pressure and posteromedial papillary muscle (PMPM) displacement during the acute phase were the most important in predicting the change in the degree of MR after 5 years. The assessment of mitral apparatus in acute phase of MI can be most useful to determine the change of the degree of MR long-term post MI. Although LV remodelling itself contributes to IMR, this influence is directly dependent on alterations in mitral geometry.

P1592 Papillary- annular continuum is a dynamic component of obstruction in outflow tract of left ventricle in patients with hypertrophic cardiomyopathy

Abstract The aim to study was to assess Strain of papillary muscles (PM) and their apical displacement with 3D mitral valve (MV) parameters with maximal size of gradient of obstruction in the left ventricle outflow tract (LVOFT) and the volume of mitral regurgitation (MR) in hypertrophic cardiomyopathy (HCMP) patients. Material and methods. 72 HCMP patients (aged of 56.9 ± 11.1 years and gradient in LVOFT 70.83 ± 14.83 mm Hg at rest) were investigated. 3D TEE of MV was performed in all patients with follow up reconstruction. Strain of anterolateral (AL) and posteromedial (PM) papillary muscles (PM) was assess by TTE. Results Strain of both PM was decreased in 45 (62.5)% patients. Positive Strain PM PM were found in 20 (27.8%) patients and AL PM -in 7 (9.7%) patients. Apical displacement of PM PM were registered in 19 (38.0%) pts and ALPM in 6 (12.0%) pts. Apical displacement of both papillary muscles was found in 10 (20.0%) patients. Pts with positive Strain of PM PM had remodeling fibrous ring of MV as compared to patients who had negative Strain of this PM (anteroposterior diameter - 1.97 ± 0.23 sm/m² vs 1.63 ± 0.20sm/m²; p = 0, 01; the perimeter of the ring - 6.92 ± 0.69 sm/m2 vs 6.09 ± 0.93sm/m2; p = 0.02; the area of the ring (3D) - 6.91 ± 1.23sm²/m² vs 5,14 ± 1.31 sm²/m²; p = 0.005). These patients had large areas of the MV leaflets (anterior 4.83 ± 1.03 sm²/m² vs 3.19 ± 0.81 sm² /m² ; p = 0.007; posterior - 4.39 ± 0.42 sm²/m² vs 3.39 ± 1.18 sm²2/m²; p = 0.004), the area of the tenting of leaflets (2.98 ± 1.64 sm²/m² vs 1.24 ± 0.61 sm²/m²; p = 0.04) and the fraction of the tenting (69, 04 ± 24.9% vs 41.27 ± 17.59; p = 0.03). Patients with positive Strain had a greater volume of mitral regurgitation (24.20 ± 11.91 ml vs 14.04 ± 7.58 ml p = 0.004) and the peak gradient in LVOFT was 88.90 ± 37.90 mm Hg vs 66.35 ± 27.00 mm Hg; p = 0.02). Thus, the parameters of 3D MV and strain of PM represent a fixed papillary – annular continuum causing a dynamic component of the obstruction in the LV OT and the volume of mitral regurgitation in patients with HCMP.

P1720 Hammock mitral valve, a challenging echocardiographic diagnosis

Abstract We report a 43 year-old female with a past TTE echocardiography of rheumatic valve disease performed in her district hospital , ( No clear symptomatology of rheumatic fever in the past). She was transferred to our tertiary hospital for elective cardiac surgery. Preoperative echocardiogram showed a non-dilated left ventricle with preserved contractility, mild-moderate left atrium enlargement with severe mitral regurgitation and basal displacement of papillary muscles and severe tricuspid regurgitation.All of it resembling a hammock mitral valve instead of former echocardiogram described as rheumatic valve disease. Preoperative cardiac study showed severe pulmonary hypertension with increased pulmonary vascular resistances. Preserved biventricular cardiac output and increased proto and telesystolic pressures. During surgery , ifindings were described as a mitral valve with a large papillary muscle inserted in the distal third of the left ventricle with none tendinous cords at the anterior leaflet and without cords in the posterior leaflet with an isolated papillary muscle with cords at A3 and P3 scallops, compatible with hammock mitral valve. A tendinous muscle/fibrous or fibromuscular band connecting the septum to the posterior wall of the left ventricle was described. Moreover over, there was an enlarged tricuspid ring with very short tendinous cords on the septal leaflet, although the leaflet was bigger than usual. Surgery consisted of resection of the mitral valve preserving A3 and P3 scallops with a 29mm Bicarbon Sorin mechanical mitral prosthesis and a 32mm Carpentier tricuspid ring implantation and pulmonary veins ablation combined with occlusion of left atrial appendage. After 112 minutes of cross-clamping time, the patient was weaned from cardiopulmonary bypass. She had important left ventricle dysfunction which improved with dobutamine and AAI pacemaker at 90lpm. Postoperative TEE showed moderate dysfunction of right ventricle, mild left ventricular dysfunction, moderate tricuspid regurgitation and a good functioning of the prosthesis. TTE before discharge showed good function of mitral valve prosthesis, good left ventricle function, mild tricuspid regurgitation, mild-moderate right ventricular enlargement, although less than preoperatively. Conclusion Congenital mitral valulophaty is a rare condition in the adulthood. The estimated prevalence is 0,5%. The hammock mitral valve is a more uncommon pathology which affects the mitral valve and subvalvular apparatus. This anomaly, was first described in 1967 and it is characterised by anomalous papillary muscles directly connected to the anterior mitral valve by a fibrous bridge without chordae tendineae in between them. This fibrous bridge hampers the opening and closure of the mitral valve. Diagnosis requires a high index of suspicion, both ultrasound studies and medical history, to avoid misdiagnosis. Abstract P1720 Figure.

P3804Left ventricular wall thickness measured with computed tomography predicts mitral regurgitation improvement in patients implanted with cardiac resynchronization therapy

Abstract Background Secondary mitral regurgitation (MR) is common in heart failure (HF) patients and results in progressive left ventricular (LV) dilatation, papillary muscle (PM) displacement and mitral valve leaflet tethering. In selected HF patients, cardiac resynchronization therapy (CRT) has been proved to reduce MR by LV reverse remodeling, resynchronization of PM insertion site contraction and reduction in MV tenting area and inter PM distance. However, data regarding the impact of LV wall thickness (WT) on MR improvement are scarce. Methods In this prospective study, a total 54 patients scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT&lt;6mm and was quantified as a percentage of total LV area. LV was segmented in 17 segments to assess the number of LV segments with reduced WT. End point was 6-month echocardiographic MR improvement by ≥1 class. For this analysis, we focused on patient with mild (class 2) to severe (class 4) MR. Results Among the 54 patients, 38 (70.4%) had mild to severe MR at baseline and a total of 16 (42.1%) experienced MR improvement by ≥1 class at 6 months. there was no difference regarding the co-morbidities, electrocardiogram and echocardiographic parameters between patients with or without MR improvement. However, patients without MR improvement had significant higher NT-pro BNP level at baseline. Interestingly, patients without MR improvement had larger LVWT &lt;6mm area (41.541.5±19.4 vs. 22.4±16.1%, p=0.003) associated with higher number of papillary muscle (PM) inserted in reduced LV WT area. In multivariate analysis, an area ≥25% of LVWT&lt;6mm including at least 1 PM insertion was the only predictor of no MR improvement at 6 months (HR 18.4 (1.25–271.75), p=0.034). Lastly, patients with MR improvement had significant lower rate of basal segments with reduced WT, especially in the lateral location. Of note, patients with MR improvement exhibited fewer rate of postero-lateral WT &lt;6mm segments. Left ventriculat segmentation Conclusion LV WT evaluated using CT is a strong predictor of no MR improvement in HF patients with mild to severe MR and who scheduled for CRT implantation.

5943Mechanistic insights of papillary muscle dyssynchrony mediated function mitral regurgitation and modulation by cardiac resynchronization

Abstract Abstract Background Mechanistic features of functional mitral regurgitation (FMR) include papillary muscle displacement due to left ventricular remodeling. Intraventricular conduction delay might further augment this condition by introducing interpapillary muscle dyssynchrony. Objectives To define this mechanism as a major contributing factor in FMR and prove the reversibility of FMR by interpapillary muscle resynchronization. Methods We enrolled 269 chronic HFrEF patients with conduction delay and comprehensively assessed dyssynchrony by complementary echocardiographic techniques. Opposing wall delay, calculated by speckle tracking, was determined as the time difference between peak longitudinal strain of the mid-anterior and inferior wall from a 2-chamber view. Furthermore, opposing wall delay was assessed as the time difference between peak strain values from tissue Doppler velocity-coded data of the mid-inferior septal and mid-lateral wall segments. Results Patients with severe FMR had markedly increased interpapillary longitudinal dyssynchrony (160ms [IQR 120–200]) compared to those with moderate (70ms [IQR 40–110]), no, or mild FMR (60ms [IQR 30–100]; P&lt;0.001). Increased interpapillary muscle dyssynchrony was correlated with effective regurgitant orifice area (P&lt;0.001; Figure A), regurgitant volume (P&lt;0.001, Figure B) and vena contracta width (P&lt;0.001, Figure C). Restoration of longitudinal papillary muscle synchronicity by cardiac resynchronization therapy (CRT) was correlated with FMR regression, as reflected by the reduction in regurgitant volume (P&lt;0.001) and vena contracta width (P&lt;0.001). Conversely, the improvement of FMR was associated with improved interpapillary radial (P=0.006) and longitudinal (P&lt;0.001) dyssynchrony. The improvement of dyssynchrony-mediated FMR signified a better prognosis compared to no improvement in FMR during the 8-year follow-up period even after comprehensive adjustment by a bootstrap-selected confounder model (adj. HR of 0.41; 95% CI 0.18–0.91; P=0.028; Figure D). The results remained virtually unchanged after adjustment for left bundle branch block. Figure 1. Dyssynchrony-FMR-CRT Conclusion Intraventricular dyssynchrony introduces unequal contraction by papillary muscle bearing walls, which has an adverse effect on FMR. CRT can effectively restore interpapillary balance and thus create a less tented leaflet configuration, resulting in a clinically meaningful reduction of FMR. The restoration of papillary muscle synchronicity in dyssynchrony-mediated FMR translates into a significantly better prognosis.

Echocardiographic assessment of mitral regurgitation

Mitral regurgitation (MR) is one of the most frequent indications for valve surgery in developed countries, and echocardiographic assessment is an essential tool to evaluate its etiologies, severity, and therapeutic indications. The mitral valve apparatus is a complex structure composed of several parts: apart from the mitral valve leaflets and annulus, it also includes the chordae tendineae, papillary muscles, and left ventricular (LV) wall. MR can be caused not only by organic changes of the mitral valve leaflets or chordae (primary MR) but also by extreme mitral annular enlargement or mitral leaflet tethering due to displacement and malfunction of papillary muscles and LV wall (secondary MR). In secondary MR with LV dysfunction, a milder degree of MR can be associated with adverse outcomes compared with primary MR. Grading the severity is the first step in evaluation of indication for surgical/transcatheter interventions. As such, there are several techniques to assess the severity of MR using echocardiography. However, none of the techniques is reliable enough by itself, and it is always recommended to integrate multiple methods. In cases where echocardiographic assessment of MR severity is inconclusive, magnetic resonance may be helpful. In addition to the severity, anatomical information, such as localization in primary MR due to mitral valve prolapse and LV size in secondary MR due to LV dilatation/dysfunction, is an important concern in presurgical echocardiography. Transesophageal echocardiography and three-dimensional echocardiography are key techniques for anatomical evaluation including mitral valve and LV volumes. In transcatheter intervention for MR, echocardiography plays a pivotal role as a guide for procedures and endpoints. In this review article, the authors provide a comprehensive summary of current standards of echocardiographic assessment of MR.

Structural abnormalities in hypertrophic cardiomyopathy beyond left ventricular hypertrophy by multimodality imaging evaluation.

Echocardiography- and cardiovascular magnetic resonance (CMR)-based studies have revealed a wide range of phenotypic manifestations in hypertrophic cardiomyopathy (HCM) apart from hypertrophy. This study sought to comprehensively describe a number of structural abnormalities in HCM beyond hypertrophy, by multimodality imaging. A total of 100 HCM patients were prospectively enrolled, undergoing standard and contrast echocardiography, and CMR. Morphological characteristics involving mitral valve leaflets (MVL), subvalvular apparatus, and left ventricular cavity and wall were investigated. Seventy healthy volunteers served as control population. As assessed by echo, MVLs were longer in HCM patients than in controls (anterior method 1: 24[22,28] vs 19[18,20] mm, P<0.01; anterior method 2: 27[24, 29] vs 21[19, 23] mm, P<0.01; posterior: 15[12,19] vs 14[13,15] mm, P<0.01). Abnormal chordal attachment to anterior MVL, anterior papillary muscle displacement, and accessory apical-basal muscle bundle were present in 42 (42%), 61 (61%), and 35 (35%) patients, respectively (P values vs controls <0.01); direct papillary muscle insertion into MVL and hypertrabeculation were found in two and five patients, respectively. Contrast echocardiography (n=94) detected myocardial crypts in 15 patients (16%). Overall, 83% of HCM subjects had at least one of these phenotypic manifestations. Echocardiography and CMR agreement for MVL length was poor, while for structural characteristics was moderate to substantial (Cohen's Kappa: 0.53-1.00). Except for posterior MVL length and hypertrabeculation, the phenotypic characteristics studied had acceptable reproducibility by echocardiography and CMR. Structural abnormalities in HCM beyond hypertrophy are significantly common. Multimodality imaging approach to these HCM facets by echocardiography and CMR is feasible and desirable.

How and where the mitral valve leaks in functional mitral regurgitation

Background and AimIt remains unknown how and where the mitral valve leaks in functional mitral regurgitation. The objective of the current study was to quantify the geometry and position of the leaflet free edges in order to reveal gapping mechanism of the mitral valve, and develop a plug technique to prevent mitral regurgitation. MethodsEight porcine mitral valves were sutured onto a dilated annulus in an in-vitro experiment to simulate valve closure at hydrostatic transmitral pressure. Eight sonocrystals were attached to the mitral valve leaflet free edges. Papillary muscles (PM) were adjusted to the normal position, and subsequently to positions of asymmetric and symmetric papillary muscle displacement. Sonocrystal positions were measured and analyzed. ResultsThe leaflet free edges in the central and medial regions moved medially, apically, and posteriorly from normal to asymmetric PM position. Gapping potential in the posteromedial region increased. Medial displacement of the free edges sometimes generated a gap in the anterolateral region in the asymmetric PM position. The leaflet free edges moved posteriorly and apically from the normal to symmetric PM position, and generated a dumb-bell shaped gap. ConclusionsAsymmetric PM position impairs the posteromedial coaptation region due to leaflet tenting, and compromises the anterolateral coaptation region due to medial leaflet displacement. The gaps include multiple sites along the coaptation line. Symmetric PM position impairs valve coaptation due to valve tenting only. The gap is a symmetrical dumb-bell shape. The findings are crucial for development of the plug technique to prevent mitral regurgitation.

Mid-term results of papillary muscles approximation: a retrospective single-center study

Background. Enlargement of the left ventricular chamber and displacement of papillary muscles in the apical and lateral directions increase the tethering forces. Left ventricular and papillary muscle desynchrony and reduced myocardial contractility reduce the closing forces, thus leading to impaired leaflet coaptation and appearance of mitral regurgitation. Therefore, treatment of mitral insufficiency requires an integrated approach, affecting all aspects of the pathogenesis of mitral regurgitation recurrence. Recent publications show that adjunctive subvalvular repair during mitral annuloplasty for secondary mitral regurgitation is effective in preventing recurrent regurgitation. One of these procedures is papillary muscle approximation. However, the safety and the positive impact of this method are still open to question. Aim. This study focused on the assessment of mid-term results of papillary muscles approximation and comparison of the obtained results with those of isolated mitral annuloplasty.Methods. Two hundred and twelve patients with ischemic cardiomyopathy and ischemic mitral regurgitation were enrolled in this retrospective single-center study. The patients were randomised to 2 groups by using propensity score matching (a “neighbor” method) according to the following parameters: end diastolic volume, end systolic volume, stroke volume and ejection fraction. The first group included 112 patients with ischemic cardiomyopathy and mitral regurgitation, who underwent coronary artery bypass grafting, mitral annuloplasty and papillary muscle approximation. The second group included 112 patients with ischemic cardiomyopathy who underwent coronary artery bypass grafting and mitral valve annuloplasty. We evaluated early and mid-term results.Results. Two patients in group 1 and three patients in group 2 died of heart failure progression during 31.3±10.4 month follow-up. According to the Kaplan-Meier analysis, no statistically significant differences were noted between the groups (log-rank test = 0.8). Approximation of papillary muscles in patients with ischemic mitral regurgitation improved mitral valve leaflet coaptation as evidenced by the values of coaptation depth, coaptation line and tenting area (p&gt;0.05). During follow-up, 3 cases (2.7%) of mitral insufficiency recurrence were recorded in group 1 and 16 (14.3%) in group 2. The Kaplan-Meier analysis of cumulative probability showed a significant difference in freedom from recurrence of mitral regurgitation ≥2 between groups in the mid-term postoperative period (log-rank test = 0.041).Conclusion. Adjunctive papillary muscle approximation performed at the time of mitral annuloplasty improves the durability of mitral valve repair. Received 18 April 2018. Revised 12 October 2018. Accepted 18 October 2018. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study.

Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography. We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01). 3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.