Mitral Annular Disjunction in Advanced Myxomatous Mitral Valve Disease: Echocardiographic Detection and Surgical Correction

Mitral annular disjunction and mitral valve prolapse: long-term risk of ventricular arrhythmias after surgery

BACKGROUND AND AIMS

Mitral valve prolapse (MVP) is associated with progressive mitral regurgitation (MR) requiring surgical correction. A subset of patients with MVP experience ventricular arrhythmias (VA), and mitral annular disjunction (MAD) has been reported as a risk factor. This study aimed to assess the long-term risk of VA in patients with MAD and MVP undergoing mitral valve surgery for MR.

METHODS

Patients with MVP with moderate or severe degenerative MR undergoing mitral valve surgery (repair or replacement) in 2010-22 at Karolinska University Hospital were included. Mitral annular disjunction length, referring to true MAD, was measured at end systole on pre- and post-operative transthoracic echocardiography. The primary outcome consisted of VA including hospitalizations, outpatient visits or ablation for confirmed sustained or non-sustained ventricular tachycardia, or high burden of premature ventricular complexes and assessed from medical records.

RESULTS

Of 599 patients undergoing mitral valve surgery, 96 (16%) had pre-operative MAD. The median MAD length was 8.0 [inter-quartile range (IQR) 5.0-10.0] mm. Compared with patients without MAD, patients with MAD were younger (55 ± 15 vs 63 ± 11 years), were more often women (31% vs 17%), and had more Barlow's disease (70% vs 27%). Mitral annular disjunction was surgically corrected in all patients. During a median follow-up time of 5.4 (IQR 2.8-7.5) years, patients with pre-operative MAD had a higher risk of VA (hazard ratio adjusted for age and sex 3.33, 95% confidence interval 1.37-8.08) regardless of repair/replacement (Pinteraction = .18).

CONCLUSIONS

Mitral annular disjunction in patients with MVP and MR was associated with a three-fold increased long-term risk of VA post-mitral valve surgery, despite anatomical correction of MAD.

Does Preliminary Chest Shape Assessment Improve the Prognostic Risk Stratification of Individuals with Mitral Annular Disjunction? A Case Report and Narrative Review

Background: Mitral annular disjunction (MAD), a mitral annular abnormality involving the whole mitral valve annulus circumference, commonly detected in individuals with mitral valve prolapse (MVP), has been recently recognized as a potential risk factor for malignant ventricular arrhythmias (VAs) and sudden cardiac death. Recent evidence indicates that a multimodality imaging assessment comprehensive of echocardiography, cardiac magnetic resonance (CMR), and cardiac computed tomography angiography (CCTA) may improve MAD detection. To date, no previous author has considered the potential influence of chest wall conformation on MAD presence. Considering the strong association between MVP and anterior chest wall deformities and the increased prevalence of MAD among MVP individuals, we have hypothesized that MAD presence might be more frequently detected among MVP individuals with a narrow anteroposterior (A-P) thoracic diameter and/or concave-shaped chest wall conformation, as noninvasively assessed by the modified Haller index (MHI). Methods: Herein, we present a case of MVP female with relevant MAD distance and moderate mitral regurgitation (MR) who underwent a diagnostic study comprehensive of transthoracic echocardiography, transesophageal echocardiography, CMR, CCTA, and exercise stress echocardiography. Results: The patient was found with a concave-shaped chest wall conformation (MHI > 2.5) and narrow A-P thoracic diameter (<13.5 cm), with a moderate and non-hemodynamically significant MR, without areas of LGE on CMR and with low arrhythmic profile. Conclusions: A preliminary chest shape assessment by the MHI might improve the prognostic risk stratification of MVP patients with MAD, potentially identifying a benign phenotype of MVP individuals, i.e., those with a narrow A-P thoracic diameter.

Shape of the mitral annulus in normal individuals and dilated cardiomyopathies: computational modeling insights into leaflet stress distribution

Introduction: The mitral valve annulus naturally adopts a saddle shape in systole, likely concentrating systolic stress on the commissures where fibrous trigones are located. This study hypothesized that in patients with dilated cardiomyopathies, where the annulus is large and planar, the stress would be redirected. Methods: Computational modeling was employed to compare the stress distribution in saddle-shaped mitral valves (n.10 patients) with planar annuli seen in dilated cardiomyopathy (n.10 patients) using kinematics of the mitral valve annulus from systole to diastole extrapolated from computed tomography angiography. Results: Simulations revealed high stress near the anterolateral and posteromedial commissures in normal valves, in contrast to high leaflet stress in planar annuli. Significant differences in stress distribution were observed near the anterolateral (S = 0.427 ± 0.053 MPa in normal valves vs S = 0.211 ± 0.123 MPa in diseased valves, p < 0.001) and posterolateral commissures (S = 0.340 ± 0.008 MPa in normal valves vs S = 0.208 ± 0.060 MPa in diseased valves, p < 0.001). Additionally, mitral annulus disjunction was present in healthy patients but absent in those with annulus planarity due to dilated cardiomyopathy. Discussion: This study suggests that while the saddle-shaped annulus focuses leaflet stress on commissures, planar annuli distribute systolic stress over leaflet surfaces. This may trigger embryonic pathways and alter mitral leaflet collagen content, ultimately leading to valve remodeling. Identifying patients with early annular planarity prior to substantial leaflet remodeling may provide early treatments to prevent increasing mitral regurgitation.

Mitral valve repair in severe mitral regurgitation due to Barlow's disease with concomitant mitral annular disjunction: a case report

BACKGROUND

Mitral annular disjunction (MAD) is characterized by the detachment of the mitral valve-left atrial junction from the left ventricular myocardium. The association of MAD with Barlow's disease and its relevance to treatment are increasingly recognized.

CASE PRESENTATION

A 75-year-old male with a history of mitral regurgitation (MR) and ablation for paroxysmal atrial fibrillation was diagnosed with severe MR due to Barlow's disease, as confirmed by echocardiography. Imaging revealed disjunction at the mitral valve's posterior annulus. During surgery, the posterior leaflet was resected along the annulus with precise height adjustments. A 6-mm separation between the mitral valve-left atrial junction and the left ventricular myocardium was sutured using a four-stitch mattress technique. The procedure included leaflet repair, insertion of artificial chordae, and mitral annuloplasty. Postoperatively, the MAD was corrected successfully, eliminating the severe MR.

CONCLUSIONS

Confirming the presence of MAD before surgery is essential for patients with MR. Surgical correction of MAD is imperative when present to address the disjunction effectively.

Mitral Annular Disjunction: A Scoping Review

Mitral annular disjunction (MAD) is the atrial displacement of the mitral valve (MV) hinge point, especially along the posterior mitral leaflet, which leads to inhomogeneous blood flow into the left ventricle, causing chronic fibrotic changes, malignant arrhythmias, and even sudden cardiac arrest. Some studies suggest that MAD is a part of normal heart morphology; however, the origin is still controversial. MAD commonly occurs with MV prolapse and myxomatous degenerative MV disease. In almost 20% of cases, MAD can occur independently as well. The prevalence of MAD in normal hearts varies from 8.6% to 96%, depending on the imaging modality and the cutoff used to define MAD. Transthoracic echocardiography is often the initial screening test, but the low sensitivity of transthoracic echocardiography to identify MAD makes it easy to miss the diagnosis altogether. More advanced imaging, especially cardiac MRI, is the gold standard for diagnosing MAD and risk stratification. MAD is an independent predictor of malignant arrhythmia. Among patients with MAD, risk stratification is based on the age at diagnosis, previous syncopal attacks, premature ventricular contractions, papillary muscle fibrosis, and longitudinal disjunction distance. Most asymptomatic patients are managed conservatively; however, radiofrequency ablation should be considered in patients with high-risk or symptomatic MAD due to the risk of ventricular arrhythmias and sudden cardiac death.

Mitral Annulus Disjunction: A Comprehensive Cardiovascular Magnetic Resonance Phenotype and Clinical Outcomes Study

BACKGROUND

Clinical importance of mitral annulus disjunction (MAD) is not well established.

PURPOSE

Characterize a population of MAD all-comers diagnosed by cardiac magnetic resonance imaging (MRI).

STUDY TYPE

Retrospective.

POPULATION

MAD confirmed in 222 patients, age of 49.2 ± 19.3 years, 126 (56.8%) males.

FIELD STRENGTH/SEQUENCE

1.5 T and 3 T/steady-state free precession and inversion recovery.

ASSESSMENT

Clinical history, outcomes, imaging, and arrhythmia data. MAD defined as a separation ≥2 mm between left ventricular myocardium and mitral annulus. Presence and pattern of late gadolinium enhancement (LGE) were analyzed. LGE in the papillary muscles and adjacent to MAD were identified as MAD related. Ventricular arrhythmias (VA) were grouped into non-sustained ventricular arrhythmias (NSVA) or sustained. Cardiovascular death assessed.

STATISTICAL TESTS

Differences between baseline characteristics were compared. Univariate regression was used to investigate possible associations between ventricular arrhythmia and cardiovascular death with characteristics associated with the severity of MAD. A multivariable logistic regression included significant variables from the univariate analysis and was performed for MAD-related and global LGE.

RESULTS

MAD extent 5.0 ± 2.6 mm. MV annulus expanded during systole for MAD ≥6 mm. Systolic expansion associated with prolapse, billowing, and curling. LGE present in 82 patients (36.9%). Twenty-three patients (10.4%) showed MAD-related LGE by three different observers. No association of LGE with MAD extent (P = 0.545) noted. Follow-up 4.1 ± 2.4 years. No sustained VA observed. In univariable analysis, NSVA was more prevalent in patients with MAD ≥6 mm (33.3% vs. 9.9%), but this was attenuated on multivariate analysis (P = 0.054). The presence of NSVA was associated with global LGE but not MAD-related LGE in isolation (P = 0.750). Three patients died of cardiovascular causes (1.4%) and none had MAD-related LGE. None died of sudden cardiac arrest.

CONCLUSION

In patients referred for cardiac MRI, mitral valve dysfunction was associated with MAD severity. Scar was not related to the extent of MAD, but associated with NSVA. The risk of sustained arrhythmias and cardiovascular death was low in this population.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

The Prevalence, Pathophysiological Role and Determinants of Mitral Annular Disjunction Among Patients with Mitral Valve Prolapse: A Systematic Review

Background: Over the last two decades, a number of imaging studies have evaluated the characteristics and clinical implications of mitral annular disjunction (MAD) among patients with mitral valve prolapse (MVP). The present systematic review has been primarily designed to summarize the main findings of these studies and to examine the overall impact of MAD in MVP patients. Methods: All imaging studies assessing the prevalence, pathophysiological role and determinants of MAD in MVP individuals, selected from the PubMed and EMBASE databases, were included. There was no limitation in terms of time period. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results: The full texts of 23 studies on 7718 MVP individuals were analyzed. The overall pooled prevalence of MAD in MVP individuals was 40% (range 5.4-90%). When considering the different imaging modalities for assessing MAD, the average MAD prevalence was 20% for cardiac computed tomography studies, 31.3% for transthoracic echocardiography (TTE) studies, 44.7% for transesophageal echocardiography studies and 47% for cardiac magnetic resonance studies. MAD presence was more commonly associated with female sex, young age, narrow antero-posterior thoracic diameter, symptoms of palpitations and syncope, T-wave inversion in inferolateral leads and frequent and/or complex ventricular arrhythmias (VAs) on electrocardiogram, myxomatous leaflets, bileaflet prolapse, larger mitral valve annulus and non-severe mitral regurgitation on TTE. A total of 12 studies (52.2%) provided follow-up data. Over a median follow-up time of 3.9 yrs (range 1-10.3 yrs), MVP individuals with MAD showed increased risk of clinical arrhythmic events, no difference in survival rate and good surgical outcomes. Conclusions: MAD was present in more than one-third of MVP patients, with a wide range of variability depending on the specific imaging method used for assessing MAD presence and on a nonunivocal MAD definition, with a possible overestimation due to Pseudo-MAD rather than True-MAD measurement. A multimodality imaging approach comprehensive of noninvasive chest shape assessment might improve MAD detection among MVP individuals. It appears that careful serial monitoring for VAs should be mandatory for MAD patients.

Outcomes of patients with mitral annular disjunction undergoing mitral valve repair†

OBJECTIVES

Mitral annular disjunction (MAD) is an abnormal displacement of the posterior mitral leaflet into the left atrial wall, potentially leading to left ventricular dysfunction, malignant ventricular arrhythmias (VA) and sudden cardiac death. This study investigates the outcomes of patients with and without MAD undergoing mitral valve repair for valve prolapse (MVP).

METHODS

The study retrospectively collected a single-center experience from 2021 to 2023 on 326 consecutive patients undergoing mitral valve repair for MVP. Patients were divided into two groups according to the presence of MAD. After propensity score matching 1:1, two comparable groups of 50 patients were obtained. Primary endpoints included hospital survival and early failure of the repair. Composite secondary endpoint included major adverse cardiac events (MACEs) such as reoperation, residual regurgitation ≥2, severe postoperative left ventricle (LV) dysfunction requiring prolonged (>3 days) inotropic support, cardiac arrhythmias and overall survival.

RESULTS

After matching, there were no significant differences between the groups in terms of preoperative characteristics. Hospital mortality was 0% in both groups, and there were no significant differences in terms of early reoperation (0%) or residual mitral regurgitation ≥2 or major atrial/VA. Nevertheless, patients with MAD presented a greater need for prolonged inotropic and mechanical circulatory support (IABP/ECMO): No-MAD 0% vs MAD 10% (P = 0.050). However, the composite outcome at midterm follow-up was similar between the groups.

CONCLUSIONS

Mitral valve repair in patients with MAD was associated with a significantly higher incidence of early LV dysfunction requiring mechanical support. However, no difference was found in terms of survival at follow-up.

Arrhythmic mitral valve complex: diagnostic and therapeutic approach

El prolapso valvular mitral arrítmico es una condición implicada en casos de muerte súbita cardiaca inexplicable que recientemente ha tomado importancia debido a los métodos diagnósticos actuales. Sin embargo, ya que la presencia de prolapso valvular mitral se ha considerado un hallazgo benigno, sus implicaciones arrítmicas han sido subestimadas. La importancia de la presente revisión es destacar parámetros clínicos y de gabinete que permitan identificar individuos con riesgo arrítmico mediante una estratificación apropiada, para así poder aplicar medidas terapéuticas oportunas y evitar desenlaces fatales.

Prevalence of Diastolic and Systolic Mitral Annular Disjunction in Patients With Mitral Valve Prolapse

BACKGROUNDS

Mitral annular disjunction (MAD) is commonly evaluated at end systole. However, a systolic-only disjunction is merely apparent, and 2 distinct phenotypes have been identified: True-MAD (atrial displacement of the posterior leaflet in diastole and systole) and Pseudo-MAD (apparent displacement in systole only). The prevalence of True-MAD and Pseudo-MAD in mitral valve prolapse (MVP) is not known. The aim of this study was to assess the prevalence of True-MAD and Pseudo-MAD in myxomatous MVP patients by transthoracic echocardiography (TTE) and to validate TTE compared to cardiac magnetic resonance (CMR; reference standards).

METHODS

Consecutive patients who underwent TTE for MVP were included. Mitral annular phenotype was evaluated in the TTE parasternal long-axis view. Accuracy (against CMR) and intra-/interrater reliability of TTE were also assessed.

RESULTS

Six hundred three consecutive patients were included. The prevalence of True-MAD and Pseudo-MAD was 7% (42) and 37% (221) (P < .05), respectively. Accordingly, 221 of 263 (84%) patients classically classified as "MAD" would have been reclassified as Pseudo-MAD. Pseudo-MAD prevalence and systolic length increased with higher mitral regurgitation (MR) severity (23% for mild MR, 36% for moderate MR, 44% for severe MR [P < .05]; 6 ± 2 mm for mild MR; 8 ± 2 mm for moderate MR; 10 ± 2 mm for severe MR [P < .05]), while True-MAD prevalence was consistent across MR grades. Pseudo-MAD was linked to systolic curling and Pickelhaube. Transthoracic echocardiography showed an overall accuracy of 0.89 (Cohen k 0.80), a substantial interrater agreement of 0.87 (k = 0.76), and an almost perfect intrarater agreement of 0.93 (k = 0.85).

CONCLUSIONS

True-MAD, unlike Pseudo-MAD, is rare in patients with MVP. Pseudo-MAD is associated with the grade of MR and other echocardiographic features of advanced myxomatous degeneration. Transthoracic echocardiography is an accurate and reliable first-line method to assess mitral annulus morphology in MVP.

Cardiovascular magnetic resonance in patients with mitral valve prolapse

With a prevalence of 2-3% in the general population, mitral valve prolapse (MVP) is the most common valvular heart disease. The clinical course is benign in the majority of patients, although severe mitral regurgitation, heart failure, and sudden cardiac death affect a non-negligible subset of patients. Imaging of MVP was confined to echocardiography until a few years ago when it became apparent that cardiovascular magnetic resonance (CMR) could offer comparative advantages for detecting and quantifying mitral valve abnormalities alongside tissue myocardial characterization. The present review highlights the growing body of evidence supporting the role of CMR in patients with MVP. Based on the recent literature, CMR appears not as a simple alternative to echocardiography in patients with poor acoustic windows, but as a complementary imaging modality instrumental for better quantifying mitral valve abnormalities, mitral regurgitation severity, ventricular remodeling, and myocardial tissue changes. In this respect, pivotal CMR studies highlight that mitral annular disjunction and myocardial fibrosis by late gadolinium enhancement are associated with a heightened risk of life-threatening ventricular arrhythmias (arrhythmic MVP). We also delineate how these and other markers (e.g., the severity of mitral regurgitation) could enable a personalized risk assessment in patients with MVP and implement clinical decision-making. Here, we provide a comprehensive review of the current literature, with an emphasis on the arrhythmic MVP phenotype. The review also provides some practical suggestions on how to carry out a dedicated CMR protocol in MVP and composes a thorough report to inform clinicians on key aspects of this valvular heart disease.

Prevalence of Mitral Annular Disjunction at Cardiac MRI: Results from a Multicenter Registry

Purpose To determine the prevalence of mitral annular disjunction (MAD) in patients undergoing cardiac MRI for various clinical indications and to assess the association of MAD with arrhythmia, mitral valve prolapse (MVP), and myocardial alteration. Materials and Methods This study analyzed data from a retrospective observational registry of consecutive patients undergoing cardiac MRI for different clinical indications. Cardiac MRI examinations were performed from January 2019 to June 2019 at 13 Italian hospitals. Images underwent double reading by expert cardiac radiologists from the enrolling center and the core laboratory to assess the presence of MAD. Presence and maximum length of MAD and its association to MVP pattern, functional and structural myocardial alteration, and arrhythmia were evaluated using nonparametric and parametric tests. Logistic regression models were used to identify predictors of arrhythmia. Results Cardiac MRI studies from 2611 consecutive patients (1730, 66% male; median age, 53 years; IQR, 39-65 years) were evaluated. Prevalence of MAD was 5.44% (142 of 2611). MAD was an incidental finding in 74.6% (106 of 142) of patients. Patients with MAD had a higher prevalence of arrhythmias compared with patients without MAD (40% [57 of 142] vs 18% [444 of 2469]; P < .001). Patients with MAD and bileaflet MVP showed a longer MAD compared with patients with single-leaflet or absent MVP (median, 7 mm [IQR, 3-9.5 mm] vs 4 mm [IQR, 3-5 mm]; P < .001), a higher prevalence of systolic curling (75% [21 of 28] vs 30.7% [35 of 114]; P < .001), higher extracellular volume values (30% [IQR, 28%-32%] vs 27% [IQR, 25%-30%]; P = .04), and a higher prevalence of arrhythmia (64.2% [18 of 28] vs 34.2% [39 of 114]; P = .006). MAD length of at least 5 mm was an independent predictor of arrhythmia (odds ratio 3.96; 95% CI: 1.93, 8.15; P < .001). Conclusion MAD was a frequent incidental finding on cardiac MRI scans from a multicenter registry. MAD length of at least 5 mm and coexisting bileaflet MVP showed a higher risk of arrhythmia. Keywords: MR Imaging, Cardiac, Mitral Annular Disjunction Supplemental material is available for this article. ©RSNA, 2024.

Case report: arrhythmic mitral valve prolapse syndrome-are risk factors underdiagnosed?

Background

Arrhythmic mitral valve prolapse syndrome (ARMV) is a recognized but underdiagnosed disease pattern. Risk factors for ARMV are established but not very well known, and the association of the structural abnormality with ventricular arrhythmias is incompletely understood.

Case summary

Here, we present the case of a young man who presented at our hospital for radiofrequency catheter ablation and mitral valve surgery after two episodes of survived sudden cardiac arrest. We discuss the diagnostic and therapeutic strategies that were used. We shine light on the risk factors for ARMV and why early identification is crucial. We address the topic of primary prevention and its limitations. Finally, we discuss different treatment modalities for patients with ARMV.

Discussion

More awareness for ARMV is crucial. A consensus statement on clinical management exists, but scientific gaps in prospective data for primary prevention need to be filled and there is a need for a better understanding of the pathogenesis of ARMV.

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.

Arrhythmogenic Mitral Valve Prolapse: Can We Risk Stratify and Prevent Sudden Cardiac Death?

Ventricular arrhythmias associated with mitral valve prolapse (MVP) and the capacity to cause sudden cardiac death (SCD), referred to as 'malignant MVP', are an increasingly recognised, albeit rare, phenomenon. SCD can occur without significant mitral regurgitation, implying an interaction between mechanical derangements affecting the mitral valve apparatus and left ventricle. Risk stratification of these arrhythmias is an important clinical and public health issue to provide precise and targeted management. Evaluation requires patient and family history, physical examination and electrophysiological and imaging-based modalities. We provide a review of arrhythmogenic MVP, exploring its epidemiology, demographics, clinical presentation, mechanisms linking MVP to SCD, markers of disease severity, testing modalities and management, and discuss the importance of risk stratification. Even with recently improved understanding, it remains challenging how best to weight the prognostic importance of clinical, imaging and electrophysiological data to determine a clear high-risk arrhythmogenic profile in which an ICD should be used for the primary prevention of SCD.

Imaging for the assessment of the arrhythmogenic potential of mitral valve prolapse

Mitral valve prolapse (MVP) is the most common valve disease in the western world and recently emerged as a possible substrate for sudden cardiac death (SCD). It is estimated an annual risk of sudden cardiac death of 0.2 to 1.9% mostly caused by complex ventricular arrhythmias (VA). Several mechanisms have been recognized as potentially responsible for arrhythmia onset in MVP, resulting from the combination of morpho-functional abnormality of the mitral valve, structural substrates (regional myocardial hypertrophy, fibrosis, Purkinje fibers activity, inflammation), and mechanical stretch. Echocardiography plays a central role in MVP diagnosis and assessment of severity of regurgitation. Several abnormalities detectable by echocardiography can be prognostic for the occurrence of VA, from morphological alteration including leaflet redundancy and thickness, mitral annular dilatation, and mitral annulus disjunction (MAD), to motion abnormalities detectable with "Pickelhaube" sign. Additionally, speckle-tracking echocardiography may identify MVP patients at higher risk for VA by detection of increased mechanical dispersion. On the other hand, cardiac magnetic resonance (CMR) has the capability to provide a comprehensive risk stratification combining the identification of morphological and motion alteration with the detection of myocardial replacement and interstitial fibrosis, making CMR an ideal method for arrhythmia risk stratification in patients with MVP. Finally, recent studies have suggested a potential role in risk stratification of new techniques such as hybrid PET-MR and late contrast enhancement CT. The purpose of this review is to provide an overview of the mitral valve prolapse syndrome with a focus on the role of imaging in arrhythmic risk stratification. CLINICAL RELEVANCE STATEMENT: Mitral valve prolapse is the most frequent valve condition potentially associated with arrhythmias. Imaging has a central role in the identification of anatomical, functional, mechanical, and structural alterations potentially associated with a higher risk of developing complex ventricular arrhythmia and sudden cardiac death. KEY POINTS: • Mitral valve prolapse is a common valve disease potentially associated with complex ventricular arrhythmia and sudden cardiac death. • The mechanism of arrhythmogenesis in mitral valve prolapse is complex and multifactorial, due to the interplay among multiple conditions including valve morphological alteration, mechanical stretch, myocardial structure remodeling with fibrosis, and inflammation. • Cardiac imaging, especially echocardiography and cardiac magnetic resonance, is crucial in the identification of several features associated with the potential risk of serious cardiac events. In particular, cardiac magnetic resonance has the advantage of being able to detect myocardial fibrosis which is currently the strongest prognosticator.

Mitral Annular Disease at Cardiac MRI: What to Know and Look For

Accurate evaluation of the mitral valve (MV) apparatus is essential for understanding the mechanisms of MV disease across various clinical scenarios. The mitral annulus (MA) is a complex and crucial structure that supports MV function; however, conventional imaging techniques have limitations in fully capturing the entirety of the MA. Moreover, recognizing annular changes might aid in identifying patients who may benefit from advanced cardiac imaging and interventions. Multimodality cardiovascular imaging plays a major role in the diagnosis, prognosis, and management of MV disease. Transthoracic echocardiography is the first-line modality for evaluation of the MA, but it has limitations. Cardiac MRI (CMR) has emerged as a robust imaging modality for assessing annular changes, with distinct advantages over other imaging techniques, including accurate flow and volumetric quantification and assessment of variations in the measurements and shape of the MA during the cardiac cycle. Mitral annular disjunction (MAD) is defined as atrial displacement of the hinge point of the MV annulus away from the ventricular myocardium, a condition that is now more frequently diagnosed and studied owing to recent technical advances in cardiac imaging. However, several unresolved issues regarding MAD, such as the functional significance of pathologic disjunction and how this disjunction advances in the clinical course, require further investigation. The authors review the role of CMR in the assessment of MA disease, with a focus on MAD and its functional implications in MV prolapse and mitral regurgitation. ©RSNA, 2024 Supplemental material is available for this article. See the invited commentary by Stojanovska and Fujikura in this issue.

Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies

Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.

Morphology of the mural and commissural atrioventricular junction of the mitral valve

OBJECTIVE

This study investigates mitral annular disjunctions (MAD) in the atrial wall-mitral annulus-ventricular wall junction along the mural mitral leaflet and commissures.

METHODS

We examined 224 adult human hearts (21.9% females, 47.9±17.6 years) devoid of cardiovascular diseases (especially mitral valve disease). These hearts were obtained during forensic medical autopsies conducted between January 2018 and June 2021. MAD was defined as a spatial displacement (≥2 mm) of the leaflet hinge line towards the left atrium. We provided a detailed morphometric analysis (disjunction height) and histological examination of MADs.

RESULTS

MADs were observed in 19.6% of all studied hearts. They appeared in 12.1% of mural leaflets. The P1 scallop was the primary site for disjunctions (8.9%), followed by the P2 scallop (5.4%) and P3 scallop (4.5%). MADs were found in 9.8% of all superolateral and 5.8% of all inferoseptal commissures. The average height for leaflet MADs was 3.0±0.6 mm, whereas that for commissural MADs was 2.1±0.5 mm (p<0.0001). The microscopical arrangement of MADs in both the mural leaflet and commissures revealed a disjunction shifted towards left atrial aspect, filled with connective tissue and covered by elongated valve annulus. The size of the MAD remained remarkably uniform and showed no correlation with other anthropometric factors (all p>0.05).

CONCLUSIONS

In the cohort of the patients with healthy hearts, MAD is present in about 20% of all studied hearts. The MADs identified tend to be localised, confined to a single scallop. Moreover, MADs in the commissures are notably smaller than those in the mural leaflet.

Arrhythmic mitral valve prolapse: a practical approach for asymptomatic patients

Mitral valve prolapse (MVP) is usually regarded as a benign condition though the proportion of patients with a life-threatening arrhythmic MVP form remains undefined. Recently, an experts' consensus statement on arrhythmic MVP has proposed approaches for risk stratification across the spectrum of clinical manifestation. However, sudden cardiac death may be the first presentation, making clinicians focused to early unmasking this subset of asymptomatic patients. Growing evidence on the role of cardiac imaging in the in-deep stratification pathway has emerged in the last decade. Pathology findings have suggested the fibrosis of papillary muscles and inferobasal left ventricular wall as the malignant hallmark. Cardiac magnetic resonance, while of limited availability, allows the identification of this arrhythmogenic substrate. Therefore, speckle-tracking echocardiography may be a gateway to prompt referring patients to further advanced imaging investigation. Our review aims to summarize the phenotypic features linked to the arrhythmic risk and to propose an image-based algorithm intended to help stratifying asymptomatic MVP patients.

Implications of Mitral Annular Disjunction in Patients Undergoing Transcatheter Edge-to-Edge Repair for Degenerative Mitral Regurgitation

BACKGROUND

Little is known about mitral transcatheter edge-to-edge repair (TEER) in patients with mitral annular disjunction (MAD).

OBJECTIVES

The authors sought to explore TEER for degenerative mitral regurgitation (MR) according to MAD status.

METHODS

We retrospectively analyzed 271 consecutive patients (median age 82 [Q1-Q3: 75-88] years, 60.9% men) undergoing an isolated, first-ever TEER for whom there were viewable preprocedural echocardiograms. Stratified by MAD status at baseline, the cohort was evaluated for all-cause mortality, heart failure hospitalizations, and mitral reinterventions-the composite of which constituted the primary outcome-as well as functional capacity and residual MR, all along the first postprocedural year.

RESULTS

Individuals with (n = 62, 22.9%) vs without MAD had more extensive prolapse and larger valve dimensions. Although the former's procedures were longer, utilizing more devices per case, technical success rate and residual MR were comparable. MAD presence was associated with higher mortality risk (HR: 2.64; 95% CI: 1.82-5.52; P = 0.014), and increased MAD length-with lower odds of functional class ≤II (OR: 0.65; 95% CI: 0.47-0.88; P = 0.006). Among 47 MAD patients with retrievable 1-month data, MAD regressed in 91.5% and by an overall 50% (Q1-Q3: 22%-100%) compared with baseline (P < 0.001). A greater MAD shortening conferred attenuated risk for the primary outcome.

CONCLUSIONS

In our experience, TEER for degenerative MR accompanied by MAD was feasible and safe; however, its postprocedural course was somewhat less favorable. MAD shortening following TEER was observed in most patients and proved prognostically beneficial.

Mitral Annular Disjunction: Clinical Implications and Surgical Considerations

Mitral annular disjunction is a cardiac structural abnormality characterized by the distinct separation between the top of the left ventricular myocardium and the mitral annulus supporting the posterior mitral leaflet occurring during systole. It has recently gained wide attention due to the increasing recognition of the link between mitral annular disjunction and arrhythmogenic mitral valve prolapse, particularly, with the increased risks of ventricular arrhythmias resulting in sudden cardiac death. This review has summarized the recent progress in the diagnostic modalities, clinical implications of mitral annular disjunction, and its specific surgical considerations.

Mitral Annular Disjunction: Review of an Increasingly Recognized Mitral Valve Entity

Mitral annular disjunction (MAD) refers to atrial displacement of the hinge point of the mitral valve annulus from the ventricular myocardium. MAD leads to paradoxical expansion of the annulus in systole and may often be associated with mitral valve prolapse (MVP), leaflet degeneration, myocardial and papillary muscle fibrosis, and, potentially, malignant cardiac arrhythmias. Patients with MAD and MVP may present similarly, and MAD is potentially the missing link in explaining why some patients with MVP experience adverse outcomes. Patients with a 5 mm or longer MAD distance have an elevated risk of malignant cardiac arrhythmia compared with those with a shorter MAD distance. Evaluation for MAD is an important component of cardiac imaging, especially in patients with MVP and unexplained cardiac arrhythmias. Cardiac MRI is an important diagnostic tool that aids in recognizing and quantifying MAD, MVP, and fibrosis in the papillary muscle and myocardium, which may predict and help improve outcomes following electrophysiology procedures and mitral valve surgery. This article reviews the history, pathophysiology, controversy, prevalence, clinical implications, and imaging considerations of MAD, focusing on cardiac MRI. Keywords: MR-Dynamic Contrast Enhanced, Cardiac, Mitral Valve, Mitral Annular Disjunction, Mitral Valve Prolapse, Floppy Mitral Valve, Cardiac MRI, Arrhythmia, Sudden Cardiac Death, Barlow Valve © RSNA, 2023.

Mitral annular disjunction in surgical mitral valve prolapse: prevalence, characteristics and outcomes

BACKGROUND

There is a paucity of literature regarding outcomes of patients with mitral valve prolapse (MVP) and mitral annular disjunction (MAD) after mitral surgery, with many unanswered questions including the post-surgical persistence of MAD, effect of MAD on mitral valve reparability, and incidence of arrhythmia after mitral valve surgery. We aimed to examine the prevalence, imaging characteristics and clinical associations of mitral annular disjunction among patients undergoing mitral valve surgery for mitral valve prolapse, as well as outcomes after surgery including the persistence of MAD, arrhythmic events and excess mortality.

RESULTS

A retrospective analysis of 111 consecutive patients who underwent mitral valve surgery for MVP was performed. A total of 32 patients (28.8%) had MAD. Patients with MAD were younger (64 vs 67 yrs, p = 0.04), with lower rates of hypertension (21.9% vs 50.6%, p = 0.01) and hyperlipidaemia (25% vs 50.6%; p = 0.01) and were more likely to be female (43.8% vs 21.4%, p = 0.04) with myxomatous leaflets > 5mm (90.6% vs 15.2%, p =  < 0.01) and bileaflet prolapse (31.3% vs 10.1%, p = 0.02). Mitral valve repair was performed in 29/32 patients (90.6%) in the MAD positive group, and no patients had the persistence of MAD post-surgery. Post-operative ventricular arrhythmia was higher in the MAD positive group (28.13% vs 11.69%, p = 0.04) with no difference in mortality, 30-day hospital re-admission, or post-operative mitral regurgitation between patients with and without MAD over 3.91 years of follow up.

CONCLUSION

In this study of consecutive patients with MVP undergoing surgery, MAD was a common finding (almost 1 in 3). MAD does not compromise mitral valve surgical reparability, and both repair and replacement are effective at correcting disjunction. Our data suggest that concurrent MAD in MVP patients undergoing surgery has no significant effect on post surgical outcomes. Further research as to whether this patient cohort requires post-surgical arrhythmia monitoring is warranted.

Mitral annular disjunction: Beyond mitral valve prolapse

Mitral annular disjunction (MAD) is an easily identifiable entity on transthoracic echocardiography, but is still poorly recognized or ignored. It is often associated with mitral valve prolapse and is itself a risk marker for ventricular arrhythmias and sudden cardiac death, but the management and risk stratification of these patients is not systematized. Two clinical cases of MAD associated with mitral valve prolapse and ventricular arrhythmias are presented. The first case is of a patient with a history of surgical intervention on the mitral valve due to Barlow's disease. He presented to the emergency department with sustained monomorphic ventricular tachycardia requiring emergent electrical cardioversion. MAD with transmural fibrosis at the level of the inferolateral wall was documented. The second report is of a young woman with palpitations and frequent premature ventricular contractions on Holter with documentation of valvular prolapse and MAD, and focuses on the risk stratification approach. The present article offers a review of the literature regarding the arrhythmic risk of MAD and mitral valve prolapse, as well as a review of risk stratification in these patients.

Arrhythmic mitral valve prolapse and mitral annular disjunction: pathophysiology, risk stratification, and management

Mitral valve prolapse (MVP) is the most frequent valve condition but remains a conundrum in many aspects, particularly in regard to the existence and frequency of an arrhythmic form (AMVP) and its link to sudden cardiac death. Furthermore, the presence, frequency, and significance of the anatomic functional feature called mitral annular disjunction (MAD) have remained widely disputed. Recent case series and cohorts have shattered the concept that MVP is most generally benign and have emphasized the various phenotypes associated with clinically significant ventricular arrhythmias, including AMVP. The definition, evaluation, follow-up, and management of AMVP represent the focus of the present review, strengthened by recent coherent studies defining an arrhythmic MVP phenotypic that would affect a small subset of patients with MVP at concentrated high risk. The role of MAD in this context is of particular importance, and this review highlights the characteristics of AMVP phenotypes and MAD, their clinical, multimodality imaging, and rhythmic evaluation. These seminal facts lead to proposing a risk stratification clinical pathway with consideration of medical, rhythmologic, and surgical management and have been objects of recent expert consensus statements and of proposals for new research directions.

Case report: Aborted sudden cardiac death as a first presentation of severe mitral annulus disjunction-a case series and review of the literature

Mitral annulus disjunction (MAD) is defined as a systolic displacement between the ventricular myocardium and the posterior mitral annulus supporting the posterior mitral leaflet. This structural abnormality is associated with the loss of mechanical annular function manifested as an abnormal systolic excursion of the leaflet hinge point into the left atrium but with maintained electrical function, separating the left atrium and ventricle electrophysiologically. The mitro-aortic fibrous continuity limits MAD anteriorly, between the aortic cusps and the anterior leaflet of the mitral valve. Consequently, MAD has been observed only at the insertion of the posterior leaflet. It can extend preferentially at the central posterior scallop. The first diagnostic modality aiding the diagnosis is transthoracic echocardiography (TTE), although in some cases adjunctive cardiac imaging modality might be suggested. MAD carries a strong association with malignant ventricular arrhythmogenesis and a profound predisposition for sudden cardiac death (SCD). In this context, a thorough investigation of this morphological and functional abnormality is vital in estimating the risk assessment and stratification for optimal management and elimination of the risk of the patient for SCD. Based on the current scientific data and literature, we will discuss the diagnosis, clinical implications, risk stratification, and therapeutic management of MAD.

Twin hearts-minimally invasive mitral valve repair in twin sisters with mitral annular disjunction and Loeys-Dietz syndrome: a case series

In this case report, we present 31-year-old twin sisters diagnosed with severe Barlow mitral valve prolapse, mitral annular disjunction and presence of lateral mid-wall fibrosis diagnosed on MRI as well as ventricular arrhythmias, and a very rare variant of Loeys-Dietz syndrome, being referred to our center for surgical repair. Genetic testing detected pathogenic variants of clinical significance in SMAD3 and KCNH2 genes that are associated with autosomal dominant disease of Loeys-Dietz syndrome. Due to the presence of severe mitral valve regurgitation, the first patient was referred for minimally invasive mitral valve repair that was performed successfully. Before discharge, a subcutaneous ICD implantation was performed as primary prevention against malignant ventricular arrhythmias and sudden cardiac death. Her twin sister presented with the identical diagnosis and underwent the same surgical procedure with S-ICD implantation a few months later.

Left Ventricle Segmental Longitudinal Strain and Regional Myocardial Work Index Could Help Determine Mitral Valve Prolapse Patients with Increased Risk of Ventricular Arrhythmias

Mitral valve prolapse (MVP) could associate with malignant ventricular arrhythmias (VAs). Mitral annular disjunction, a putative mechanism for an arrhythmic substrate, leads to excessive mobility, stretch, and damage of some segments. Speckle tracking echocardiography (STE), with particular attention to the segmental longitudinal strain and myocardial work index (MWI), could be an indicator of the segments we aimed to check. Seventy-two MVP patients and twenty controls underwent echocardiography. Complex VAs documented prospectively after the enrollment was qualified as the primary endpoint, which was noticed in 29 (40%) patients. Pre-specified cut-off values for peak segmental longitudinal strain (PSS) and segmental MWI for basal lateral (-25%, 2200 mmHg%), mid-lateral (-25%, 2500 mmHg%), mid-posterior (-25%, 2400 mmHg%), and mid-inferior (-23%, 2400 mmHg%) segments were accurate predictors of complex VAs. A combination of PSS and MWI increased the probability of the endpoint, reaching the highest predictive value for the basal lateral segment: odds ratio 32.15 (3.78-273.8), p < 0.001 for PSS ≥ -25% and MWI ≥ 2200 mmHg%. STE may be a valuable tool for assessing the arrhythmic risk in MVP patients. Excessively increased segmental longitudinal strain with an augmented regional myocardial work index identifies patients with the highest risk of complex VAs.

The influence of chest wall conformation on myocardial strain parameters in a cohort of mitral valve prolapse patients with and without mitral annular disjunction

PURPOSE

To evaluate the possible influence of chest wall conformation on myocardial strain parameters in a cohort of mitral valve prolapse (MVP) patients with and without mitral annular disjunction (MAD).

METHODS

All consecutive middle-aged patients with MVP referred to our Outpatient Cardiology Clinic for performing two-dimensional (2D) transthoracic echocardiography (TTE) as part of work up for primary cardiovascular prevention between March 2018 and May 2022, were included into the study. All patients underwent clinic visit, physical examination, modified Haller index (MHI) assessment (the ratio of chest transverse diameter over the distance between sternum and spine) and conventional 2D-TTE implemented with speckle tracking analysis of left ventricular (LV) global longitudinal strain (GLS) and global circumferential strain (GCS). Independent predictors of MAD presence on 2D-TTE were assessed.

RESULTS

A total of 93 MVP patients (54.2 ± 16.4 yrs, 50.5% females) were prospectively analyzed. On 2D-TTE, 34.4% of MVP patients had MAD (7.3 ± 2.0 mm), whereas 65.6% did not. Compared to patients without MAD, those with MAD had: 1) significantly shorter antero-posterior (A-P) thoracic diameter (13.5 ± 1.2 vs 14.8 ± 1.3 cm, p < 0.001); 2) significantly smaller cardiac chambers dimensions; 3) significantly increased prevalence of classic MVP (84.3 vs 44.3%, p < 0.001); 4) significantly impaired LV-GLS (-17.2 ± 1.4 vs -19.4 ± 3.0%, p < 0.001) and LV-GCS (-16.3 ± 4.1 vs -20.4 ± 4.9, p < 0.001), despite similar LV ejection fraction (63.7 ± 4.2 vs 63.0 ± 3.9%, p = 0.42). A-P thoracic diameter (OR 0.25, 95%CI 0.10-0.82), classic MVP (OR 3.90, 95%CI 1.32-11.5) and mitral annular end-systolic A-P diameter (OR 2.76, 95%CI 1.54-4.92) were the main independent predictors of MAD. An A-P thoracic diameter ≤ 13.5 cm had 59% sensitivity and 84% specificity for predicting MAD presence (AUC = 0.81). In addition, MAD distance was strongly influenced by A-P thoracic diameter (r = - 0.96) and MHI (r = 0.87), but not by L-L thoracic diameter (r = 0.23). Finally, a strong inverse correlation between MHI and both LV-GLS and LV-GCS was demonstrated in MAD patients (r = - 0.94 and - 0.92, respectively), but not in those without (r = - 0.51 and - 0.50, respectively).

CONCLUSIONS

A narrow A-P thoracic diameter is strongly associated with MAD presence and is a major determinant of the impairment in myocardial strain parameters in MAD patients, in both longitudinal and circumferential directions.

Mitral Valve Prolapse and Sudden Cardiac Death in Athletes at High Risk

Mitral valve prolapse (MVP) is the most frequent valvulopathy in the general population, with usually a favourable prognosis. Although it can be associated with some complications, ventricular arrhythmias (VA) and sudden cardiac death (SCD) are the most worrying. The estimated risk of SCD in MVP is between 0.2% to 1.9% per year, including MVP patients with and without severe mitral regurgitation (MR). The association between SCD and MVP is expressed by a phenotype called "malignant MVP" characterized by transthoracic echocardiography (TTE) findings such as bileaflet myxomatous prolapse and mitral annulus disjunction (MAD), ECG findings such as repolarization abnormalities, complex ventricular arrhythmias (c-VAs) and LV fibrosis of papillary muscles (PMs) and inferobasal wall visualized by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Therefore, attention is raised for patients with "arrhythmic MVP" characterized from an ECG point of view by frequent premature ventricular contractions (PVCs) arising from one or both PMs as well as by T-wave inversion in the inferolateral leads. In athletes, SCD is the most frequent medical cause of death and in young subjects (< 35 years) usually is due to electrical mechanism affecting who has a silent cardiovascular disease and are not considered per se a cause of increased mortality. In MVP, SCD was reported to happen during sports activity or immediately after and valve prolapse was the only pathological aspect detected. The aim of the present paper is to explore the association between SCD and MVP in athletes, focusing attention on ECG, TTE in particular, and CMR findings that could help to identify subjects at high risk for complex arrhythmias and eventually SCD. In addition, it is also examined if sports activity might predispose patients with MVP to develop major arrhythmias.

Characterization of ventricular arrhythmias and sudden cardiac death in subjects with mitral valve prolapse and mitral annular disjunction

Sudden cardiac death is reported as the leading cause of mortality in developed nations. Arrhythmic mitral valve disease, encompassing mitral valve prolapse and/or mitral annular disjunction, is thought to be responsible in a sizable portion of these deaths. Despite this evidence, there are no reliable methods or clinically useful risk stratification schemes to determine which group of patients are at higher risk or may benefit from interventions such as catheter ablation or prophylactic implantation of a defibrillator. The reasons for this lack of guidance include our incomplete understanding of the mechanisms of ventricular arrhythmias and the fact that mitral valve prolapse and disjunction are frequently diagnosed, yet carry an overall low risk of sudden cardiac death. This heterogeneity makes the development of a reliable prediction model based on the presence of common risk factors very difficult. In this review, we summarize the relevant literature regarding the epidemiology, diagnosis, pathophysiology, and management of mitral valve prolapse and mitral annular disjunction and elucidate their role in sudden cardiac death.

Echocardiographic description and outcomes in a heterogeneous cohort of patients undergoing mitral valve surgery with and without mitral annular disjunction: a health service evaluation

Background

Mitral annular disjunction (MAD) is a structural abnormality characterized by the distinct separation of the mitral valve annulus/left atrium wall and myocardium. Little is known about the significance of MAD in patients requiring mitral valve surgery. This evaluation evaluates the echocardiographic characteristics and patient outcomes for patients with and without MAD who require mitral valve surgery.

Methods

All patients who underwent mitral valve surgery and who had a pre-surgical transthoracic echocardiogram between 2013 and 2020 were included. Patient demographics and clinical outcomes were collected on review of patient electronic records.

Results

A total of 185 patients were included in the analysis of which 32.4% had MAD (average MAD length 8.4 mm). MAD was seen most commonly in patients with mitral valve prolapse and myxomatous mitral valves disease (90% and 60% respectively). In the patients with MAD prior to mitral valve surgery, only 3.9% had MAD post mitral valve surgery. There were no significant difference in the severity of post-operative mitral regurgitation, arrhythmic events or major adverse cardiovascular events in patients with and without MAD.

Conclusions

MAD is common in patients who undergo mitral valve surgery. Current surgical techniques are able to correct the MAD abnormality in the vast majority of patients. MAD is not associated with an increased risk of adverse clinical outcomes post mitral valve surgery.

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.

Mapping of the myxomatous mitral valve: The three-dimensional extension of mitral annular disjunction in surgically repaired mitral prolapse

Objectives

This study aimed to describe the heterogeneous extension of mitral annular disjunction (MAD) and assess the hypotesis that different phenotypes of disjunction are not associated with increased surgical challenges.

Background

Mitral regurgitation (MR) is the most common end-stage scenario of degenerative mitral valve disease (DMVD). Few data exist on the three-dimensional extension and geometry of MAD, as well as for its role in valvular dynamic and coaptation.

Methods

A total of 85 consecutive subjects, who underwent elective mitral valve repair (MVR) for MMVD at our Institution between November 2019 and October 2021, were studied retrospectively. The extension and geometry of MAD was assessed using the digitally stored volumetric datasets of real-time 3D transesophageal echocardiography (TEE). Annular phenotypes and surgical repair techniques were analyzed.

Results

Mitral annular disjunction was diagnosed in 50 out of 85 patients (59%) with Barlow disease (BD). A detailed analysis of MAD extension was conducted on 33 patients. Two pattern of disjunction were identified: a bimodal shape was highlighted in 21 patients, while a more uniform distribution of the disjuncted annulus was observed in 12 patients. The bimodal pattern was characterized by lower disjunction distance (DD) at the 140°–220° arch (3.6 ± 2.2 mm), while a more regular DD was measured in the remaining patients. All patients successfully underwent MVR. Triangular leaflet resection was performed in 58% of the cases, neochordae implantation in 9%, and notably a 27% received an isolated annuloplasty.

Conclusion

Rather than a binary feature, MAD should be taken into account in its complex and heterogeneous morphology, where two major phenotypes can be identified. Despite its anatomical complexity, MAD was not associated with an increased surgical challenge; conversely a peculiar subgroup of patient was successfully treated with an isolated annuloplasty.

Mitral Annular Disjunction Assessed Using CMR Imaging: Insights From the UK Biobank Population Study

BACKGROUND

Mitral annular disjunction is the atrial displacement of the mural mitral valve leaflet hinge point within the atrioventricular junction. Said to be associated with malignant ventricular arrhythmias and sudden death, its prevalence in the general population is not known.

OBJECTIVES

The purpose of this study was to assess the frequency of occurrence and extent of mitral annular disjunction in a large population cohort.

METHODS

The authors assessed the cardiac magnetic resonance (CMR) images in 2,646 Caucasian subjects enrolled in the UK Biobank imaging study, measuring the length of disjunction at 4 points around the mitral annulus, assessing for presence of prolapse or billowing of the leaflets, and for curling motion of the inferolateral left ventricular wall.

RESULTS

From 2,607 included participants, the authors found disjunction in 1,990 (76%) cases, most commonly at the anterior and inferior ventricular wall. The authors found inferolateral disjunction, reported as clinically important, in 134 (5%) cases. Prolapse was more frequent in subjects with disjunction (odds ratio [OR]: 2.5; P = 0.02), with positive associations found between systolic curling and disjunction at any site (OR: 3.6; P < 0.01), and systolic curling and prolapse (OR: 71.9; P < 0.01).

CONCLUSIONS

This large-scale study shows that disjunction is a common finding when using CMR. Disjunction at the inferolateral ventricular wall, however, was rare. The authors found associations between disjunction and both prolapse and billowing of the mural mitral valve leaflet. These findings support the notion that only extensive inferolateral disjunction, when found, warrants consideration of further investigation, but disjunction elsewhere in the annulus should be considered a normal finding.

Substrate Characterization and Outcomes of Catheter Ablation of Ventricular Arrhythmias in Patients With Mitral Annular Disjunction

BACKGROUND

Mitral annular disjunction (MAD) has recently been recognized as an arrhythmogenic entity. Data on the electrophysiological substrate as well as the outcomes of catheter ablation of ventricular arrhythmias in patients with MAD is limited.

METHODS

Forty patients with MAD (mean age 47±15 years; 70% female) underwent catheter ablation for ventricular arrhythmias. Detailed clinical, electrocardiographic, cardiac imaging, and procedural data were collected. Clinical outcomes were compared between patients who had substrate modification in the MAD area and those who did not.

RESULTS

Twenty-three (57.5%) patients had ablation for premature ventricular contractions, 10 (25%) patients for sustained ventricular tachycardia, and 7 (17.5%) patients for premature ventricular contraction-triggered ventricular fibrillation ablation. Mean end-systolic MAD length was 10.58±3.49 mm on transthoracic echocardiography. Seventeen (42.5%) patients had preprocedural cardiac magnetic resonance imaging, and 5 (29%) patients had late gadolinium enhancement. Among the 18 (45%) patients who had abnormal local electrograms (low voltage, long-duration, fractionated, isolated mid-diastolic potentials) during electroanatomical mapping, 10 (25%) patients had abnormal electrograms in the anterolateral mitral annulus or MAD area. Substrate modification was performed in 10 (25%) patients. Catheter ablation was acutely successful in 36 (90%) patients (elimination of premature ventricular contraction or noninducibility of ventricular tachycardia). After a median follow-up duration of 54.08 (interquartile range, 10.67-89.79) months, premature ventricular contraction burden decreased from a median of 9.75% (interquartile range, 3.25-14) before the ablation to a median of 4% (interquartile range, 1-7.75) after the ablation (P=0.03 [95% CI, 0.055-6.5]). Eight (20.5%) patients had repeat ablation for ventricular arrhythmias. Substrate modification of the MAD was associated with a trend toward lower rates of repeat ablation (0% versus 26.7%; P=0.16).

CONCLUSIONS

Patients with MAD have a complex arrhythmogenic substrate, and catheter ablation is effective in reducing recurrence of ventricular arrhythmias. Substrate mapping and ablation may be considered in these patients.

Imaging Considerations and Clinical Implications of Mitral Annular Disjunction

Mitral annular disjunction is increasingly recognized as an important anatomic feature of mitral valve disease. The presence of mitral annular disjunction, defined as separation between the left atrial wall at the point of mitral valve insertion and the left ventricular free wall, has been associated with increased degeneration of the mitral valve and increased incidence of sudden cardiac death. The clinical importance of this entity necessitates standard reporting on cardiovascular imaging reports if patients are to receive adequate risk stratification and management. We provide a narrative review of the literature pertaining to mitral annular disjunction, its clinical implications, and areas needing further research.

Mitral annular disjunction: A case series and review of the literature

Mitral annular disjunction (MAD) is an abnormal displacement of the mitral valve leaflet onto the left atrial wall and is commonly found in patients with mitral valve prolapse (MVP). The diagnosis is usually made by transthoracic echocardiography (TTE) although findings can be subtle and further cardiac imaging may be necessary. MAD has been associated with a risk of malignant ventricular arrhythmias and sudden cardiac death, therefore recognition of this diagnosis and risk stratification are highly important. In this review, we will discuss the diagnosis, clinical implications, risk stratification and management of MAD based upon currently available literature, as well as provide a series of cases showing the heterogeneity in presentation and our experience with management of this rare but potentially fatal entity.

Arrhythmogenic Mitral Valve Prolapse

Mitral valve prolapse (MVP) is a common condition present in 1–3% of the population. There has been evidence that a subset of MVP patients is at higher risk of sudden cardiac death. The arrhythmogenic mechanism is related to fibrotic changes in the papillary muscles caused by the prolapsing valve. ECG features include ST-segment depression, T wave inversion or biphasic T waves in inferior leads, and premature ventricular contractions arising from the papillary muscles and the fascicular system. Echocardiography can identify MVP and mitral annular disjunction, a feature that has significant negative prognostic value in MVP. Cardiac MRI is indicated for identifying fibrosis. Patients with high-risk features should be referred for further evaluation. Catheter ablation and mitral valve repair might reduce the risk of malignant arrhythmia. MVP patients with high-risk features and clinically documented ventricular arrhythmia may also be considered for an ICD.

Prevalence and prognostic impact of mitral annular disjunction in patients with STEMI - A cardiac magnetic resonance study

BACKGROUND

Mitral annular disjunction (MAD) represents the detachment of the mitral leaflet hinge-point from the ventricular myocardium. Its role in patients with ST-segment-elevation myocardial infarction (STEMI) is unknown. This study aims to investigate the prevalence of MAD by cardiac magnetic resonance imaging (CMR) in STEMI-patients and its association with serious adverse events.

METHODS

STEMI-patients (n = 621) underwent CMR 4 days [interquartile range (IQR) 2-5] after percutaneous coronary intervention. Presence and longitudinal extent of MAD were obtained in long-axis cine-images, infarct characteristics in late gadolinium enhancement-images. During a median follow-up time of 366 days (IQR 136-454), patients were observed for the occurrence of major adverse cardiac events (MACE), comprising death, myocardial reinfarction, and congestive heart failure.

RESULTS

Overall, 307 patients (49 %) had MAD. Longitudinal MAD-distance was 4.6 ± 1.7 mm and the P3-segment was affected most frequently (n = 262, 85 % of MAD-patients). MAD-patients had a significantly smaller infarct size, lower prevalence of microvascular obstruction, and intramyocardial hemorrhage as well as a higher ejection fraction (all p < 0.03). During follow-up period, MACE occurred in 52 patients (8 %) and did not show significant difference between patients with and without MAD (7 % vs. 9 %, p = 0.424). Cardiovascular death occurred significantly more often in patients without MAD (n = 10, 3.2 % vs. n = 2, 0.7 %, p = 0.021).

CONCLUSION

MAD is a rather common finding in patients presenting with STEMI. Patients with MAD had less severe infarct characteristics, however, they were not more commonly affected by MACE. Further confirmation and longer follow-up intervals are necessary to define the exact role of MAD in STEMI patients.

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.

Echocardiographic Assessment of Mitral Annular Disjunction With Cross-Correlation by Computed Tomography and Magnetic Resonance Imaging: A Case Series

Mitral valve (MV) pathology, along with its associated peripheral anatomy, is one of the most common categories of heart disease. Two-dimensional (2D) transthoracic echocardiography (TTE) plays a prominent role in the detection and management of various types MV disease, specifically mitral annular disjunction (MAD). MAD is defined as a structural abnormality of the mitral annulus fibrosus, causing a noticeable gap between the atrial wall-mitral valve junction and the basilar portion of the left ventricular free wall (LV). The integral role that cardiac sonographers play in identifying MAD cannot be underscored, as well as the risk of easily overlooking this unique abnormality. Often associated with mitral valve prolapse (MVP), accurate documentation of MAD amid an echocardiographic study can have positive implications on patient prognosis. This case series highlights the echocardiographic characteristics of MAD, to raise awareness of this often forgotten feature of myxomatous mitral valves, which can indeed cause adverse patient outcomes. It is important to demonstrate correlational features with additional imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT).

Malignant Mitral Valve Prolapse: Risk and Prevention of Sudden Cardiac Death

Purpose of review

The purpose of this review is to explore the prevalence and risk factors for a malignant phenotype in mitral valve prolapse (MVP) characterized by life-threatening ventricular arrhythmias and sudden cardiac arrest and death (SCD), including mechanistic and pathophysiologic findings and mechanism-based potential therapies.

Recent findings

A malignant phenotype in MVP characterized by life-threatening arrhythmias has long been recognized, although MVP is often benign. Efforts to identify this malignant phenotype have revealed potential risk factors for SCD that include elongated, myxomatous leaflets, ECG changes and complex ventricular ectopy. More recently, malignant MVP has been associated with myocardial fibrosis in the papillary muscles and inferobasal left ventricular wall. This localization suggests a central role of prolapse-induced mechanical forces on the myocardium in creating an arrhythmogenic substrate and triggering life-threatening arrhythmias. This mechanism for fibrosis is also consistent with imaging evidence of prolapse-induced mechanical changes in the papillary muscles and inferobasal left ventricular wall. Currently, no therapy to prevent SCD in malignant MVP has been established and limited clinical data are available. Mechanistic information and prospective study have the potential to identify patients at risk of SCD and preventive strategies.

Summary

Malignant MVP relates to unique properties and mechanical abnormalities in the mitral valve apparatus and adjacent myocardium. Increased understanding of disease mechanisms and determinants of arrhythmias is needed to establish effective therapies.

Arrhythmic Mitral Valve Prolapse and Mitral Annular Disjunction: Clinical Features, Pathophysiology, Risk Stratification, and Management

Mitral valve prolapse (MVP) is a common cause of valvular heart disease. Although many patients with MVP have a benign course, there is increasing recognition of an arrhythmic phenotype associated with ventricular arrhythmias and sudden cardiac death (SCD). Pathophysiologic mechanisms associated with arrhythmias include cardiac fibrosis, mechanical stress induced changes in ventricular refractory periods, as well as electrophysiologic changes in Purkinje fibers. Clinically, a variety of risk factors including demographic, electrocardiographic, and imaging characteristics help to identify patients with MVP at the highest at risk of SCD and arrhythmias. Once identified, recent advances in treatment including device therapy, catheter ablation, and surgical interventions show promising outcomes. In this review, we will summarize the incidence of ventricular arrhythmias and SCD in patients with MVP, the association with mitral annular disjunction, mechanisms of arrhythmogenesis, methods for arrhythmic and SCD risk stratification including findings with multimodality imaging, and treatments for the primary and secondary prevention of SCD.

Definition, prevalence, and clinical significance of mitral annular disjunction in different patient cohorts: A systematic review

BACKGROUND

Mitral annular disjunction (MAD) is a structural abnormality involving a distinct separation of the left atrium/mitral valve annulus and myocardium continuum. The literature around MAD has increased over recent years, thus we sought to review the current data on the definition, prevalence, and clinical outcomes of MAD.

METHODS

A search of MEDLINE and EMBASE was conducted to identify studies which evaluated MAD in any patient cohort. The study results were synthesized narratively.

RESULTS

A total of 12 studies were included with 3925 patients (average age 62 years, 63% male). The pooled prevalence of MAD in patients with mitral valve prolapse and/or Barlow's disease was 30.1%. In a general population, MAD prevalence was 8.7%. The definition of MAD was not consistent across all studies. In terms of clinical outcomes, only one study reported MAD to be associated with ventricular arrhythmias.

CONCLUSIONS

MAD is an increasingly recognized finding amongst patients undergoing cardiac imaging. This review highlights the need for agreed definitions for clinically significant MAD and how identified MAD should be managed. At present, there is insufficient evidence that MAD is associated adverse clinical outcomes.

Diagnosis of Mitral Valve Prolapse: Much More than Simple Prolapse. Multimodality Approach to Risk Stratification and Therapeutic Management

Mitral valve prolapse (MVP) is the most common valvular disease with a prevalence of 2%. It has generally a benign course; however, recent findings suggested an association between MVP and complex arrhythmias and eventually cardiac arrest and for this reason, it is also called arrhythmogenic MVP. Subjects who experience this complication are in general young women, with thickened mitral leaflets or bileaflet prolapse not necessarily associated with severe mitral regurgitation (MR). The nature of the relation between MVP and cardiac arrest is not clearly understood. Actually, the challenging task is to find the cluster of prognostic factors including T-wave inversion, polymorphic premature ventricular contractions, bileaflet prolapse, MR severity, but most importantly, those parameters of hypercontractility, mitral annulus disjunction (MAD), and myocardial fibrosis using a multimodality approach. Transthoracic echocardiography is the first-line imaging modality for the diagnosis of MVP, but also for detecting MAD and hypercontractility, followed by cardiac magnetic resonance for tissue characterization and detection of myocardial and papillary muscle fibrosis, using either late gadolinium enhancement (at the basal segment of the inferolateral wall and papillary muscles) (macro-fibrosis), or diffuse fibrosis by T1 mapping (native and post contrast T1). Moreover, there are also preliminary data on positron emission tomography utilizing 18F-fluorodeoxyglucose as a tool for providing evidence of early myocardial inflammation. The objective of this review article is to provide the clinician with an overview and a practical clinical approach to MVP for risk stratification and treatment guidance.