Mitral Valve Prolapse Patients with Less than Moderate Mitral Regurgitation Exhibit Early Cardiac Chamber Remodeling

Cardiac magnetic resonance imaging in the evaluation and management of mitral valve prolapse - a comprehensive review

Mitral valve prolapse is a common valve disorder that usually has a benign prognosis unless there is significant regurgitation or LV impairment. However, a subset of patients are at an increased risk of ventricular arrhythmias and sudden cardiac death, which has led to the recognition of "arrhythmic mitral valve prolapse" as a clinical entity. Emerging risk factors include mitral annular disjunction and myocardial fibrosis. While echocardiography remains the primary method of evaluation, cardiac magnetic resonance has become crucial in managing this condition. Cine magnetic resonance sequences provide accurate characterization of prolapse and annular disjunction, assessment of ventricular volumes and function, identification of early dysfunction and remodeling, and quantitative assessment of mitral regurgitation when integrated with flow imaging. However, the unique strength of magnetic resonance lies in its ability to identify tissue changes. T1 mapping sequences identify diffuse fibrosis, in turn related to early ventricular dysfunction and remodeling. Late gadolinium enhancement sequences detect replacement fibrosis, an independent risk factor for ventricular arrhythmias and sudden cardiac death. There are consensus documents and reviews on the use of cardiac magnetic resonance specifically in arrhythmic mitral valve prolapse. However, in this article, we propose an algorithm for the broader use of cardiac magnetic resonance in managing this condition in various scenarios. Future advancements may involve implementing techniques for tissue characterization and flow analysis, such as 4D flow imaging, to identify patients with ventricular dysfunction and remodeling, increased arrhythmic risk, and more accurate grading of mitral regurgitation, ultimately benefiting patient selection for surgical therapy.

Impact of Sex on Severity Assessment and Cardiac Remodeling in Primary Mitral Regurgitation

Background

Women with severe primary mitral regurgitation (MR) have lower surgery rates than men and could suffer from delayed referral for mitral valve (MV) intervention, exposing them to an increased risk of postoperative adverse outcomes.

Objectives

The purpose of this study was to assess the sex-based differences in patients with primary MR.

Methods

The study sample consisted of 420 patients (median age: 62 years, 26% women) with primary MR due to valve prolapse referred for preoperative assessment who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging. Multiple endpoints (abnormally increased left ventricular size, NYHA functional class III/IV, severe left atrial [LA] dilatation, pulmonary hypertension) were studied using areas under the curves and logistic regression models.

Results

Women were older than men, had higher NYHA functional class and larger indexed LA volumes (all P ≤ 0.031), despite displaying lower MR effective regurgitant orifice area, regurgitant volumes (RegVol), and ventricular volumes than men (all P ≤ 0.002). The optimal cut-off values of RegVol associated with abnormally increased left ventricular size according to reference normal values were lower in women (TTE: 67 ml, CMR: 50 ml) than in men (TTE: 77 ml, CMR: 65 ml). MR regurgitant fraction, but not RegVol, was associated in women and men with NYHA functional class III/IV, severe LA dilatation, and pulmonary hypertension (all areas under the curves, P ≤ 0.024).

Conclusions

Despite having hallmarks of more advanced valvular heart disease, women with significant primary MR demonstrate lower mitral RegVol and ventricular volumes than men. In contrast, the systematic calculation of MR regurgitant fraction could standardize MR quantification irrespective of sex.

Arrhythmic Mitral Valve Prolapse Phenotype: An Unsupervised Machine Learning Analysis Using a Multicenter Cardiac MRI Registry

Purpose To use unsupervised machine learning to identify phenotypic clusters with increased risk of arrhythmic mitral valve prolapse (MVP). Materials and Methods This retrospective study included patients with MVP without hemodynamically significant mitral regurgitation or left ventricular (LV) dysfunction undergoing late gadolinium enhancement (LGE) cardiac MRI between October 2007 and June 2020 in 15 European tertiary centers. The study end point was a composite of sustained ventricular tachycardia, (aborted) sudden cardiac death, or unexplained syncope. Unsupervised data-driven hierarchical k-mean algorithm was utilized to identify phenotypic clusters. The association between clusters and the study end point was assessed by Cox proportional hazards model. Results A total of 474 patients (mean age, 47 years ± 16 [SD]; 244 female, 230 male) with two phenotypic clusters were identified. Patients in cluster 2 (199 of 474, 42%) had more severe mitral valve degeneration (ie, bileaflet MVP and leaflet displacement), left and right heart chamber remodeling, and myocardial fibrosis as assessed with LGE cardiac MRI than those in cluster 1. Demographic and clinical features (ie, symptoms, arrhythmias at Holter monitoring) had negligible contribution in differentiating the two clusters. Compared with cluster 1, the risk of developing the study end point over a median follow-up of 39 months was significantly higher in cluster 2 patients (hazard ratio: 3.79 [95% CI: 1.19, 12.12], P = .02) after adjustment for LGE extent. Conclusion Among patients with MVP without significant mitral regurgitation or LV dysfunction, unsupervised machine learning enabled the identification of two phenotypic clusters with distinct arrhythmic outcomes based primarily on cardiac MRI features. These results encourage the use of in-depth imaging-based phenotyping for implementing arrhythmic risk prediction in MVP. Keywords: MR Imaging, Cardiac, Cardiac MRI, Mitral Valve Prolapse, Cluster Analysis, Ventricular Arrhythmia, Sudden Cardiac Death, Unsupervised Machine Learning Supplemental material is available for this article. © RSNA, 2024.

Noncomplex ventricular arrhythmia associated with greater freedom from recurrent ectopy at 1 year after mitral repair surgery

Objective

The effect of mitral valve (MV) surgery on the natural history of ventricular arrhythmia (VA) in patients with arrhythmic MV prolapse remains unknown. We sought to evaluate the cumulative incidence of VA at 1 year after surgical mitral repair.

Methods

A retrospective review of progressively captured data identified 204 consecutive patients who underwent elective MV repair for significant degenerative mitral regurgitation as a first-time cardiovascular intervention in a quaternary reference center between January 2018 and December 2020. A subset of 62 consecutive patients with diagnosed arrhythmic MV prolapse was further evaluated for recurrent VA after MV repair.

Results

The median age was 62 years (range, 27-77 years) and 26 of 62 (41.9%) were female. The median time from initial mitral regurgitation/MV prolaspe diagnosis-to-referral was 13.8 years (interquartile range [IQR], 5.4-25) and from VA diagnosis-to-referral was 8 years (IQR, 3-10.6). Using the Lown-Wolf classification, complex VA (Lown grade ≥3) was identified in 36 of 62 patients (58%) at baseline, whereas 8 of 62 (13%) had a cardioverter/defibrillator implanted for primary (4/8) or secondary (4/8) prevention. Left ventricular myocardial scar was confirmed in 23 of 34 (68%) of patients scanned at baseline. The prevailing valve phenotype was bileaflet Barlow (59/62; 95.2%). All patients underwent surgical MV repair by the same team. Surgical repair was stabilized with an annuloplasty prosthesis (median size 36 mm [IQR, 34-38]). Concomitant procedures included tricuspid valve repair (51/62; 82.3%), cryo-maze ± left atrial appendage exclusion (14/62, 23%), and endocardial cryoablation of VA ectopy (4/62; 6.5%). The 30-day and 1-year freedom from recurrent VA were 98.4% and 75.9%, respectively. Absent VA after mitral repair was uniformly observed in patients with minor VA at baseline. Absent VA after mitral repair was uniformly observed in patients with minor VA preoperatively. Complex baseline VA was the strongest predictor of recurrent VA (hazard ratio, 10.8; 95% confidence interval, 1.4-84.2; P = .024), irrespective of myocardial fibrosis.

Conclusions

In a series of 62 consecutive patients operated electively for arrhythmic mitral prolapse, VA remained undetected in 75.9% of patients at 1 year. Freedom from recurrent VA was greater among patients without complex VA preoperatively, whereas baseline Lown grade ≥3 was the strongest independent risk factor for recurrent VA at 1 year. These findings attest to the importance of early recognition and prompt referral of patients with mitral prolapse and progressive VA to specialty interdisciplinary care.

Primary Atriopathy in Mitral Valve Prolapse: Echocardiographic Evidence and Clinical Implications

BACKGROUND

Prominent multi-scallop systolic leaflet displacement toward the left atrium (atrialization) is typically observed in bileaflet mitral valve prolapse (MVP) with mitral annular disjunction. We hypothesized that mitral leaflet atrialization is associated with an underlying left atrial (LA) myopathy characterized by progressive structural and functional abnormalities, irrespective of mitral regurgitation (MR) severity.

METHODS

We identified 334 consecutive patients with MVP, no prior atrial fibrillation, and comprehensive clinical and echocardiographic data. LA function was assessed by LA reservoir strain, LA function index, and LA emptying fraction. We also classified the stage of LA remodeling based on LA enlargement and LA reservoir strain (stage 1: no remodeling; stage 2: mild remodeling; stage 3: moderate remodeling; and stage 4: severe remodeling). The primary end point was the composite risk of sudden arrhythmic death, heart failure hospitalization, or the new onset of atrial fibrillation.

RESULTS

Bileaflet MVP with no or mild MR had a lower LA reservoir strain (P=0.04) and LA function index (P<0.001) compared with other MVP subtypes. In multivariable linear regression adjusted for cardiovascular risk factors and MR ≥moderate, bileaflet MVP remained significantly associated with lower LA function parameters (all P<0.05). There was a significant increase in the risk of events as the LA reservoir strain and LA remodeling stage increased (P<0.001). In multivariable analysis, stage 4 of LA remodeling remained significantly associated with a higher risk of events compared with stage 1 (hazard ratio, 6.09 [95% CI, 1.69-21.9]; P=0.006).

CONCLUSIONS

In a large MVP registry, bileaflet involvement is associated with reduced LA function regardless of MR severity, suggesting a primary atriopathy in this MVP subtype. Abnormal LA function, particularly when assessed through a multiparametric approach, is linked to a higher risk of cardiovascular events and may improve risk stratification in MVP, even in those without significant MR.

What Do We Know So Far About Ventricular Arrhythmias and Sudden Cardiac Death Prediction in the Mitral Valve Prolapse Population? Could Biomarkers Help Us Predict Their Occurrence?

PURPOSE OF THE REVIEW

To summarize currently available data on the topic of mitral valve prolapse (MVP) and its correlation to the occurrence of atrial and ventricular arrhythmias. To assess the prognostic value of several diagnostic methods such as transthoracic echocardiography, transesophageal echocardiography, cardiac magnetic resonance, cardiac computed tomography, electrocardiography, and electrophysiology concerning arrhythmic episodes. To explore intra and extracellular biochemistry of the cardiovascular system and its biomarkers as diagnostic tools to predict rhythm disturbances in the MVP population.

RECENT FINDINGS

MVP is a common and mainly benign valvular disorder. It affects 2-3% of the general population. MVP is a heterogeneous and highly variable phenomenon with three structural phenotypes: myxomatous degeneration, fibroelastic deficiency, and forme fruste. Exercise intolerance, supraventricular tachycardia, and chest discomfort are the symptoms that are often paired with psychosomatic components. Though MVP is thought to be benign, the association between isolated MVP without mitral regurgitation (MR) or left ventricle dysfunction, with ventricular arrhythmia (VA) and sudden cardiac death (SCD) has been observed. The incidence of SCD in the MVP population is around 0.6% per year, which is 6 times higher than the occurrence of SCD in the general population. Often asymptomatic MVP population poses a challenge to screen for VA and prevent SCD. Therefore, it is crucial to carefully assess the risk of VA and SCD in patients with MVP with the use of various tools such as diagnostic imaging and biochemical and genetic screening.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

Degenerative mitral regurgitation

Degenerative mitral regurgitation is a major threat to public health and affects at least 24 million people worldwide, with an estimated 0.88 million disability-adjusted life years and 34,000 deaths in 2019. Improving access to diagnostic testing and to timely curative therapies such as surgical mitral valve repair will improve the outcomes of many individuals. Imaging such as echocardiography and cardiac magnetic resonance allow accurate diagnosis and have provided new insights for a better definition of the most appropriate timing for intervention. Advances in surgical techniques allow minimally invasive treatment with durable results that last for ≥20 years. Transcatheter therapies can provide good results in select patients who are considered high risk for surgery and have a suitable anatomy; the durability of such repairs is up to 5 years. Translational science has provided new knowledge on the pathophysiology of degenerative mitral regurgitation and may pave the road to the development of medical therapies that could be used to halt the progression of the disease.

Perspectives on Secondary Mitral Regurgitation in Heart Failure

PURPOSE OF THE REVIEW

This review focuses on broader perspectives of mitral regurgitation (MR) in patients with heart failure.

RECENT FINDINGS

The ratio of regurgitant volume to end-diastolic volume appears to help identify patients who may benefit from valve interventions. Secondary MR is not only attributed to geometric changes of the LV but also related to the structural changes in the mitral valve that include fibrosis of the mitral leaflets and changes in the extracellular matrix. The transition from mild to severe secondary MR can occur at different rates, from a slow LV remodeling process to a more abrupt process precipitated by an inciting event such as atrial fibrillation. Septal flash and apical rocking, two new visual markers of LV mechanical dyssynchrony, appear to be predictive of MR reduction following cardiac resynchronization therapy. Optimal guideline-directed medical therapy has been shown to decrease the severity of secondary MR effectively. A theoretical framework to characterize secondary MR as it relates to the onset of MR is proposed. Type A: Early onset of MR contemporaneous with myocardial injury. The maladaptive LV remodeling occurs in parallel with MR. Type B: LV remodeling proceeds without significant MR until the LV is moderately dilated, which coincides with or without inciting factors such as atrial fibrillation. Type C: LV remodeling proceeds after myocardial injury without significant MR until the LV is severely dilated. MR is a late manifestation of LV remodeling.

Machine Learning-Based Phenogrouping in MVP Identifies Profiles Associated With Myocardial Fibrosis and Cardiovascular Events

BACKGROUND

Structural changes and myocardial fibrosis quantification by cardiac imaging have become increasingly important to predict cardiovascular events in patients with mitral valve prolapse (MVP). In this setting, it is likely that an unsupervised approach using machine learning may improve their risk assessment.

OBJECTIVES

This study used machine learning to improve the risk assessment of patients with MVP by identifying echocardiographic phenotypes and their respective association with myocardial fibrosis and prognosis.

METHODS

Clusters were constructed using echocardiographic variables in a bicentric cohort of patients with MVP (n = 429, age 54 ± 15 years) and subsequently investigated for their association with myocardial fibrosis (assessed by cardiac magnetic resonance) and cardiovascular outcomes.

RESULTS

Mitral regurgitation (MR) was severe in 195 (45%) patients. Four clusters were identified: cluster 1 comprised no remodeling with mainly mild MR, cluster 2 was a transitional cluster, cluster 3 included significant left ventricular (LV) and left atrial (LA) remodeling with severe MR, and cluster 4 included remodeling with a drop in LV systolic strain. Clusters 3 and 4 featured more myocardial fibrosis than clusters 1 and 2 (P < 0.0001) and were associated with higher rates of cardiovascular events. Cluster analysis significantly improved diagnostic accuracy over conventional analysis. The decision tree identified the severity of MR along with LV systolic strain <21% and indexed LA volume >42 mL/m2 as the 3 most relevant variables to correctly classify participants into 1 of the echocardiographic profiles.

CONCLUSIONS

Clustering enabled the identification of 4 clusters with distinct echocardiographic LV and LA remodeling profiles associated with myocardial fibrosis and clinical outcomes. Our findings suggest that a simple algorithm based on only 3 key variables (severity of MR, LV systolic strain, and indexed LA volume) may help risk stratification and decision making in patients with MVP. (Genetic and Phenotypic Characteristics of Mitral Valve Prolapse, NCT03884426; Myocardial Characterization of Arrhythmogenic Mitral Valve Prolapse [MVP STAMP], NCT02879825).

Arrhythmic mitral valve prolapse in 2023: Evidence-based update

Patients with mitral valve prolapse (MVP) may develop ventricular arrhythmias, ranging from premature ventricular contractions through more complex non-sustained ventricular tachycardia to sustained life-threatening ventricular arrhythmias. The prevalence of MVP in autopsy series of young adults who died suddenly has been estimated to be between 4% and 7%. Thus, "arrhythmic MVP" has been reported as an underappreciated cause of sudden cardiac death, leading to a renewed interest in the study of this association. The term "arrhythmic MVP" refers to a small subset of patients who have, in the absence of any other arrhythmic substrate, MVP, with or without mitral annular disjunction, and frequent or complex ventricular arrhythmias. Our understanding of their coexistence in terms of contemporary management and prognosis is still incomplete. While literature regarding the arrhythmic MVP may be contrasting despite recent consensus document, the present review summarizes the relevant evidence concerning the diagnostic approach, prognostic implications, and targeted therapies for MVP-related ventricular arrhythmias. We also summarize recent data supporting left ventricular remodeling, which complicates the coexistence of MVP with ventricular arrhythmias. As the evidence for a putative link between MVP-associated ventricular arrhythmias and sudden cardiac death is scarce and based on scant and retrospective data, risk prediction remains a challenge. Thus, we aimed at listing potential risk factors from available seminal reports for further use in a more reliable prediction model that requires additional prospective data. Finally, we summarize evidence and guidelines on targeted therapies of ventricular arrhythmias in the setting of MVP, including implantable cardioverter defibrillators and catheter ablation. Our review highlights current knowledge gaps and provides an action plan for structured research on the pathophysiological genesis, diagnosis, prognostic impact, and optimal management of patients with arrhythmic MVP.

Valvular heart disease: shifting the focus to the myocardium

Adverse cardiac remodelling is the main determinant of patient prognosis in degenerative valvular heart disease (VHD). However, to give an indication for valvular intervention, current guidelines include parameters of cardiac chamber dilatation or function which are subject to variability, do not directly reflect myocardial structural changes, and, more importantly, seem to be not sensitive enough in depicting early signs of myocardial dysfunction before irreversible myocardial damage has occurred. To avoid irreversible myocardial dysfunction, novel biomarkers are advocated to help refining indications for intervention and risk stratification. Advanced echocardiographic modalities, including strain analysis, and magnetic resonance imaging have shown to be promising in providing new tools to depict the important switch from adaptive to maladaptive myocardial changes in response to severe VHD. This review, therefore, summarizes the current available evidence on the role of these new imaging biomarkers in degenerative VHD, aiming at shifting the clinical perspective from a valve-centred to a myocardium-focused approach for patient management and therapeutic decision-making.

Myocardial Fibrosis at Cardiac MRI Helps Predict Adverse Clinical Outcome in Patients with Mitral Valve Prolapse

Background Patients with mitral valve prolapse (MVP) may develop adverse outcomes even in the absence of mitral regurgitation or left ventricular (LV) dysfunction. Purpose To investigate the prognostic value of mitral annulus disjunction (MAD) and myocardial fibrosis at late gadolinium enhancement (LGE) cardiac MRI in patients with MVP without moderate-to-severe mitral regurgitation or LV dysfunction. Materials and Methods In this longitudinal retrospective study, 118 144 cardiac MRI studies were evaluated between October 2007 and June 2020 at 15 European tertiary medical centers. Follow-up was from the date of cardiac MRI examination to June 2020; the minimum and maximum follow-up intervals were 6 months and 156 months, respectively. Patients were excluded if at least one of the following conditions was present: cardiomyopathy, LV ejection fraction less than 40%, ischemic heart disease, congenital heart disease, inflammatory heart disease, moderate or worse mitral regurgitation, participation in competitive sport, or electrocardiogram suggestive of channelopathies. In the remainder, cardiac MRI studies were reanalyzed, and patients were included if they were aged 18 years or older, MVP was diagnosed at cardiac MRI, and clinical information and electrocardiogram monitoring were available within 3 months from cardiac MRI examination. The end point was a composite of adverse outcomes: sustained ventricular tachycardia (VT), sudden cardiac death (SCD), or unexplained syncope. Multivariable Cox regression analysis was performed. Results A total of 474 patients (mean age, 47 years ± 16 [SD]; 244 women) were included. Over a median follow-up of 3.3 years, 18 patients (4%) reached the study end point. LGE presence (hazard ratio, 4.2 [95% CI: 1.5, 11.9]; P = .006) and extent (hazard ratio, 1.2 per 1% increase [95% CI: 1.1, 1.4]; P = .006), but not MAD presence (P = .89), were associated with clinical outcome. LGE presence had incremental prognostic value over MVP severity and sustained VT and aborted SCD at baseline (area under the receiver operating characteristic curve, 0.70 vs 0.62; P = .03). Conclusion In contrast to mitral annulus disjunction, myocardial fibrosis determined according to late gadolinium enhancement at cardiac MRI was associated with adverse outcome in patients with mitral valve prolapse without moderate-to-severe mitral regurgitation or left ventricular dysfunction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Gerber in this issue.

Mitral Annular Disjunction: Associated Pathologies and Clinical Consequences

PURPOSE OF REVIEW

To provide an overview of mitral annular disjunction (MAD) and to discuss important challenges in diagnosis and management of MAD.

RECENT FINDINGS

MAD has regained interest in the context of sudden cardiac death (SCD) in patients with mitral valve prolapse (MVP), coined as the "arrhythmic" MVP syndrome. In addition, MAD in isolation was recently suggested to be associated with severe arrhythmia and SCD. There is a lack of consensus on the definition of MAD and the imaging modality to be used for diagnosing MAD, and the therapeutic implications of MAD remain uncertain. Furthermore, the exact mechanism underlying the association of MAD with SCD remains largely unexplored.

Mitral Valve Prolapse-The Role of Cardiac Imaging Modalities

Mitral valve prolapse (MVP) is the most common nonischemic mitral regurgitation etiology and mitral abnormality requiring surgery in the Western world. There is an increasing awareness that pathological findings in MVP are not confined to the valve tissue; rather, it is a complex disease, involving the mitral valve apparatus, cardiac hemodynamics, and cardiac structure. Imaging has played a fundamental role in the understanding of the diagnosis, prevalence, and consequences of MVP. The diagnosis of MVP by imaging is based upon demonstrating valve leaflets ascending into the left atrium through the saddle-shaped annulus. Transthoracic and transesophageal echocardiography are the primary modalities in the diagnosis and assessment of MVP patients and must include careful assessment of the leaflets, annulus, chords, and papillary muscles. High-spatial-resolution imaging modalities such as cardiac magnetic resonance images and cardiac computed tomography play a secondary role in this regard and can demonstrate the anatomical relation between the mitral valve annulus and leaflet excursion for appropriate diagnosis. Ongoing development of new methods of cardiac imaging can help us to accurately understand the mechanism, diagnose the disease, develop an appropriate treatment plan, and estimate the risk for sudden death. Recently, several new observations with respect to prolapse have been derived from cardiac imaging including three-dimensional echocardiography and tissue-Doppler imaging. The aim of this article is to present these new imaging-derived insights for the diagnosis, risk assessment, treatment, and follow-up of patients with MVP.

Left Ventricular Remodeling in Non-syndromic Mitral Valve Prolapse: Volume Overload or Concomitant Cardiomyopathy?

Mitral valve prolapse (MVP) is a common valvular disorder that can be associated with mitral regurgitation (MR), heart failure, ventricular arrhythmias and sudden cardiac death. Given the prognostic impact of these conditions, it is important to evaluate not only mitral valve morphology and regurgitation, but also the presence of left ventricular (LV) function and remodeling. To date, several possible hypotheses have been proposed regarding the underlying mechanisms of LV remodeling in the context of non-syndromic MVP, but the exact pathophysiological explanation remains elusive. Overall, volume overload related to severe MR is considered the main cause of LV dilatation in MVP. However, significant LV remodeling has been observed in patients with MVP and no/mild MR, particularly in patients with bileaflet MVP or Barlow’s disease, generating several new hypotheses. Recently, the concept of “prolapse volume” was introduced, adding a significant volume load to the LV on top of the transvalvular MR volume. Another possible hypothesis is the existence of a concomitant cardiomyopathy, supported by the link between MVP and myocardial fibrosis. The origin of this cardiomyopathy could be either genetic, a second hit (e.g., on top of genetic predisposition) and/or frequent ventricular ectopic beats. This review provides an overview of the different mechanisms and remaining questions regarding LV remodeling in non-syndromic MVP. Since technical specifications of imaging modalities impact the evaluation of MR severity and LV remodeling, and therefore might influence clinical decision making in these patients, this review will also discuss assessment of MVP using different imaging modalities.

Clinical Features and Outcomes in Adults With Childhood Repair of Partial Atrioventricular Septal Defect

Background

Partial atrioventricular septal defects (pAVSDs) are mostly repaired in childhood; however, there are limited data describing these patients in adulthood.

Objectives

The objective of this study was to describe clinical course and associations with outcomes in adults with repaired pAVSDs.

Methods

A retrospective review of adults (≥18 years) with pAVSDs repaired in childhood who presented to the Adult Congenital Heart Disease Clinic at our institution was conducted.

Results

Of 121 patients, the median age was 31 years (IQR: 22-43 years) and 71.9% were female. The median number of operations at the time of presentation was 1 (IQR: 1-2). Left atrioventricular valve (LAVV) replacement had been performed in 19.8% of patients. Among those with native LAVV, 41.2% had ≥ moderate regurgitation. Atrial arrhythmias were present in 34.7% and were associated with later age at repair (P = 0.02) and a high number of prior surgeries (P = 0.005). Estimated systolic pulmonary artery pressure >40 mmHg was seen in 19.8%. Over 4 (IQR: 1-12) years of follow-up, death occurred in 13 (10.7%) patients and reoperation was required in 39.7%. One-third had a LAVV prosthesis by the end of the study. Atrial fibrillation was independently associated with death or hospitalization on multivariable analysis.

Conclusions

In this cohort of adults with pAVSDs repaired in childhood, atrial fibrillation was common at a young age and associated with worse outcomes. Thus, more studies are needed evaluating the cause of this arrhythmia burden and possible associated atrial myopathy. While many require surgery in adulthood, more information is needed regarding indications for and impacts of LAVV intervention as one-third had an LAVV prosthesis by the end of follow-up.

Arrhythmias in Patients With Valvular Heart Disease: Gaps in Knowledge and the Way Forward

The prevalence of both organic valvular heart disease (VHD) and cardiac arrhythmias is high in the general population, and their coexistence is common. Both VHD and arrhythmias in the elderly lead to an elevated risk of hospitalization and use of health services. However, the relationships of the two conditions is not fully understood and our understanding of their coexistence in terms of contemporary management and prognosis is still limited. VHD-induced left ventricular dysfunction/hypertrophy and left atrial dilation lead to both atrial and ventricular arrhythmias. On the other hand, arrhythmias can be considered as an independent condition resulting from a coexisting ischemic or non-ischemic substrate or idiopathic ectopy. Both atrial and ventricular VHD-induced arrhythmias may contribute to clinical worsening and be a turning point in the natural history of VHD. Symptoms developed in patients with VHD are not specific and may be attributable to hemodynamical consequences of valve disease but also to other cardiac conditions including arrhythmias which are notably prevalent in this population. The issue how to distinguish symptoms related to VHD from those related to atrial fibrillation (AF) during decision making process remains challenging. Moreover, AF is a traditional limit of echocardiography and an important source of errors in assessment of the severity of VHD. Despite recent progress in understanding the pathophysiology and prognosis of postoperative AF, many questions remain regarding its prevention and management. Furthermore, life-threatening ventricular arrhythmias can predispose patients with VHD to sudden cardiac death. Evidence for a putative link between arrhythmias and outcome in VHD is growing but available data on targeted therapies for VHD-related arrhythmias, including monitoring and catheter ablation, is scarce. Despite growing evidences, more research focused on the prognosis and optimal management of VHD-related arrhythmias is still required. We aimed to review the current evidence and identify gaps in knowledge about the prevalence, prognostic considerations, and treatment of atrial and ventricular arrhythmias in common subtypes of organic VHD.

Influence of Prolapse Volume in Mitral Valve Prolapse

Mitral valve prolapse (MVP) is characterized by excessive leaflet tissue leading to a wide spectrum of mitral regurgitation (MR) ranging from trivial to severe. The prolapse volume (PV) below the prolapsing leaflets in end-systole was suspected to impact both chamber remodeling and MR grading in MVP. Based on 157 consecutive patients (45 women; mean age 62±15) referred for CMR assessment of MR, either from MVP (n = 91; 58%) or fibroelastic disease (FED) (n = 66; 42%), we sought to study (i) the interaction between PV and cardiac chamber geometry (ii) to study the impact of PV on MR quantification in MVP. Despite similar left ventricular (LV) size, PV was larger in MVP (11±9ml) than in FED (2±2ml). PV progressively increased with the severity of MR in MVP but not in FED. Despite a low regurgitant volume (32±18ml), some MVP patients with less than moderate MR exhibit significant cardiac chambers remodeling compared to 52 age and sex-matched controls. PV correlated significantly (r = 0.52) with the LV dilatation in severe MR but also in less than moderate MR. In MVP, PV>14ml was associated with a significant underestimation (Bias=-26±32ml) of regurgitant volume by PISA compared to CMR. In conclusion, in MVP, PV may play a role in left cardiac chambers remodeling, even in patients without severe MR, and in discordant grading of MR between echocardiography and CMR.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

Replacement Myocardial Fibrosis in Patients With Mitral Valve Prolapse: Relation to Mitral Regurgitation, Ventricular Remodeling, and Arrhythmia

BACKGROUND

Mitral valve prolapse (MVP) is a frequent disease that can be complicated by mitral regurgitation (MR), heart failure, arterial embolism, rhythm disorders, and death. Left ventricular (LV) replacement myocardial fibrosis, a marker of maladaptive remodeling, has been described in patients with MVP, but the implications of this finding remain scarcely explored. We aimed at assessing the prevalence, pathophysiological and prognostic significance of LV replacement myocardial fibrosis through late gadolinium enhancement (LGE) by cardiac magnetic resonance in patients with MVP.

METHODS

Four hundred patients (53±15 years of age, 55% male) with MVP (trace to severe MR by echocardiography) from 2 centers, who underwent a comprehensive echocardiography and LGE cardiac magnetic resonance, were included. Correlates of replacement myocardial fibrosis (LGE+), influence of MR degree, and ventricular arrhythmia were assessed. The primary outcome was a composite of cardiovascular events (cardiac death, heart failure, new-onset atrial fibrillation, arterial embolism, and life-threatening ventricular arrhythmia).

RESULTS

Replacement myocardial fibrosis (LGE+) was observed in 110 patients (28%; 91 with myocardial wall including 71 with basal inferolateral wall, 29 with papillary muscle). LGE+ prevalence was 13% in trace-mild MR, 28% in moderate MR, and 37% in severe MR, and was associated with specific features of mitral valve apparatus, more dilated LV and more frequent ventricular arrhythmias (45% versus 26%, P<0.0001). In trace-mild MR, despite the absence of significant volume overload, abnormal LV dilatation was observed in 16% of patients and ventricular arrhythmia in 25%. Correlates of LGE+ in multivariable analysis were LV mass (odds ratio, 1.01 [95% CI, 1.002-1.017], P=0.009) and moderate-severe MR (odds ratio, 2.28 [95% CI, 1.21-4.31], P=0.011). LGE+ was associated with worse 4-year cardiovascular event-free survival (49.6±11.7 in LGE+ versus 73.3±6.5% in LGE-, P<0.0001). In a stepwise multivariable Cox model, MR volume and LGE+ (hazard ratio, 2.6 [1.4-4.9], P=0.002) were associated with poor outcome.

CONCLUSIONS

LV replacement myocardial fibrosis is frequent in patients with MVP; is associated with mitral valve apparatus alteration, more dilated LV, MR grade, and ventricular arrhythmia; and is independently associated with cardiovascular events. These findings suggest an MVP-related myocardial disease. Last, cardiac magnetic resonance provides additional information to echocardiography in MVP.