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

Age-related changes in mitral annular disjunction: A retrospective analysis using enhanced cardiac CT

AIMS

The current recognition of mitral annular disjunction (MAD) as an anatomical abnormality potentially associated with ventricular arrhythmias has sparked controversy regarding its prevalence and clinical implications. This study aimed to investigate the prevalence and extent of MAD in individuals with no significant structural abnormalities involving the left heart using enhanced cardiac CT, while also exploring potential factors, such as age, that may be associated with MAD.

METHODS

Systolic datasets of cardiac CT from 742 subjects were retrospectively included. MAD was determined by rotating orthogonal multiplanar reconstruction images around the central axis of the mitral annulus. The maximal distance of disjunction (DMAD) and segments involved (SI, 0 to 5 basal segments at left ventricular wall) was quantified to evaluate the extent of separation.

RESULTS

In total, 449 (60.5%) had MAD. Subjects with MAD were significantly older (51.3 ± 19.9 years vs. 29.6 ± 20.3 years, P < 0.001). Age was found to be an independent relevant factor for MAD (OR = 1.059; 95%CI: 1.033, 1.085; P < 0.001). Subjects with MAD were then divided into 4 subgroups (G1: ≤20 years, G2: 21-40 years, G3: 41-60 years, G4: ≥61 years). DMAD and SI of each age subgroup were 1.9 ± 0.2 mm, 2.0 ± 1.2 (G1, n = 36), 2.7 ± 0.8 mm, 2.9 ± 1.3 (G2, n = 51), 3.0 ± 0.8 mm, 3.0 ± 1.3 (G3, n = 183), and 3.0 ± 1.0 mm, 3.7 ± 1.1 (G4, n = 179). Age was an independent relevant factor associated with DMAD (R2 = 0.132; β = 0.014; 95%CI: 0.004, 0.024; P = 0.007) and SI (OR = 1.030; 95%CI: 1.005, 1.055; P = 0.016).

CONCLUSIONS

MAD is a common finding on cardiac CT. Its prevalence and extent increase with age.

Role of cardiac magnetic resonance in stratifying arrhythmogenic risk in mitral valve prolapse patients: a systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis of studies investigating the diagnostic value of cardiac magnetic resonance (CMR) features for arrhythmic risk stratification in mitral valve prolapse (MVP) patients.

MATERIALS AND METHODS

EMBASE, PubMed/MEDLINE, and CENTRAL were searched for studies reporting MVP patients who underwent CMR with assessment of: left ventricular (LV) size and function, mitral regurgitation (MR), prolapse distance, mitral annular disjunction (MAD), curling, late gadolinium enhancement (LGE), and T1 mapping, and reported the association with arrhythmia. The primary endpoint was complex ventricular arrhythmias (co-VAs) as defined by any non-sustained ventricular tachycardia, sustained ventricular tachycardia, ventricular fibrillation, or aborted sudden cardiac death. Meta-analysis was performed when at least three studies investigated a CMR feature. PROSPERO registration number: CRD42023374185.

RESULTS

The meta-analysis included 11 studies with 1278 patients. MR severity, leaflet length/thickness, curling, MAD distance, and mapping techniques were not meta-analyzed as reported in < 3 studies. LV end-diastolic volume index, LV ejection fraction, and prolapse distance showed small non-significant effect sizes. LGE showed a strong and significant association with co-VA with a LogORs of 2.12 (95% confidence interval (CI): [1.00, 3.23]), for MAD the log odds-ratio was 0.95 (95% CI: [0.30, 1.60]). The predictive accuracy of LGE was substantial, with a hierarchical summary ROC AUC of 0.83 (95% CI: [0.69, 0.91]) and sensitivity and specificity rates of 0.70 (95% CI: [0.41, 0.89]) and 0.80 (95% CI: [0.67, 0.89]), respectively.

CONCLUSIONS

Our study highlights the role of LGE as the key CMR feature for arrhythmia risk stratification in MVP patients. MAD might complement arrhythmic risk stratification.

CLINICAL RELEVANCE STATEMENT

LGE is a key factor for arrhythmogenic risk in MVP patients, with additional contribution from MAD. Combining MRI findings with clinical characteristics is critical for evaluating and accurately stratifying arrhythmogenic risk in MVP patients.

KEY POINTS

MVP affects 2-3% of the population, with some facing increased risk for arrhythmia. LGE can assess arrhythmia risk, and MAD may further stratify patients. CMR is critical for MVP arrhythmia risk stratification, making it essential in a comprehensive evaluation.

Mitral Annular Disjunction in the Context of Mitral Valve Prolapse: Identifying the At-Risk Patient

Mitral annular disjunction (MAD), a separation between the left atrium/mitral valve annulus and the left ventricular myocardium, is frequently seen in patients with arrhythmic mitral valve prolapse. Although an association exists between MAD and ventricular arrhythmias, little is known regarding the identification of individuals at high risk. Multimodality imaging including echocardiography, computed tomography, cardiac magnetic resonance, and positron emission tomography can play an important role in both the diagnosis and risk stratification of MAD. Due to a paucity of data, clinical decision making in a patient with MAD is challenging and remains largely empirical. Although MAD itself can be corrected surgically, the prevention and treatment of associated arrhythmias may require medical therapy, catheter ablation, and an implantable cardioverter-defibrillator. Prospective data are required to define the role of implantable cardioverter-defibrillators, targeted catheter ablation, and surgical correction in selected, at-risk patients.

Floppy Mitral Valve/Mitral Valve Prolapse and Manifestations Not Related to Mitral Regurgitation: Time to Search the Dark Side of the Moon

BACKGROUND

Floppy mitral valve/mitral valve prolapse (FMV/MVP) is a complex entity in which several clinical manifestations are not directly related to the severity of mitral regurgitation (MR).

SUMMARY

Patients with FMV/MVP and trivial to mild MR may have exercise intolerance, orthostatic phenomena, syncope/presyncope, chest pain, and ventricular arrhythmias, among others. Several anatomical and pathophysiologic consequences related to the abnormal mitral valve apparatus and to prolapse of the mitral leaflets into the left atrium provide some explanation for these symptoms. Further, it should be emphasized that MVP is a non-specific finding, while FMV (redundant mitral leaflets, elongated/rupture chordae tendineae, annular dilatation) is the central issue in the MVP story.

KEY MESSAGE

The purpose of this review was to highlight the clinical manifestations of FMV/MVP not directly related to the severity of MR and to discuss the pathophysiologic mechanisms contributing to these manifestations.

Mitral annular disjunction and its progression during childhood in Marfan syndrome

AIMS

Data on mitral annular disjunction (MAD) in children with Marfan syndrome (MFS) are sparse. To investigate the diagnostic yield of MAD by echocardiography and cardiac magnetic resonance imaging (CMR), its prevalence and progression during childhood.

METHODS AND RESULTS

We included patients <21 years old with MFS, defined by 2010 Ghent criteria and a pathogenic FBN1 variant or ectopia lentis. Two readers measured systolic separation between the mitral valve (MV) posterior hinge point and left ventricular (LV) myocardium on initial and subsequent imaging. MAD was defined as MV-LV separation ≥2 mm, MV prolapse (MVP) as atrial displacement ≥2 mm. Kappa coefficients evaluated echocardiogram-CMR agreement. Bland-Altman and intraclass correlation coefficients (ICCs) assessed inter-rater and inter-modality reliability. Univariable mixed-effects linear regression was used to evaluate longitudinal changes of MAD. MAD was detected in 60% (110/185) eligible patients. MVP was present in 48% (53/110) of MAD and MAD in 90% (53/59) of MVP. MAD detection by CMR and echocardiography had 96% overall agreement (Kappa = 0.89, P < 0.001) and a 0.32 mm estimate bias (95% CI 0.00, 0.65). ICC by echocardiography, CMR, and between modalities were 0.97 (95% CI 0.93, 0.98), 0.92 (95% CI 0.79, 0.97), and 0.91 (95% CI 0.85, 0.94), respectively. MAD was associated with aortic root dilation (P < 0.001). MAD was found in children of all ages, increased +0.18 mm/year (95% CI +0.14, +0.22) during a median duration of 5.5 years (IQR 3.1, 7.5 years). MAD indexed by height yielded a constant value +0.0002 mm/m/year (95% CI -0.0002, +0.0005 mm/m/year).

CONCLUSION

MAD was common in pediatric MFS and was associated with aortic root dilation. MAD detection by echocardiography and CMR was highly reliable, suggesting that routine assessment in MFS is feasible. MAD was present in neonates and progressed over time but remained constant when indexing by height. Further studies are needed to evaluate MAD as a biomarker for clinical outcomes in pediatric MFS.

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.

Mitral annulus disjunction in consecutive patients undergoing cardiovascular magnetic resonance: Where is the boundary between normality and disease?

BACKGROUND

The presence of mitral annulus disjunction (MAD) has been considered a high-risk feature for sudden cardiac death based on selected study populations. We aimed to assess the prevalence of MAD in consecutive patients undergoing clinically indicated cardiovascular magnetic resonance (CMR), its association with ventricular arrhythmias, mitral valve prolapse (MVP), and other CMR features.

METHODS

This single-center retrospective study included consecutive patients referred to CMR at our institution between June 2021 and November 2021. MAD was defined as a ≥1 mm displacement between the left atrial wall-mitral valve leaflet junction and the left ventricular wall during end-systole. MAD extent was defined as the maximum longitudinal displacement. Associates of MAD were evaluated at univariable and multivariable regression analysis. The study endpoint, a composite of (aborted) sudden cardiac death, unexplained syncope, and sustained ventricular tachycardia, was evaluated at a 12-month follow-up.

RESULTS

Four hundred and forty-one patients 55 ± 18 years, 267/441 (61%) males) were included, and 29/441 (7%) had MVP. The prevalence of MAD ≥1 mm, 4 mm, and 6 mm was 214/441 (49%), 63/441 (14%), and 15/441 (3%), respectively. Patients with MVP showed a higher prevalence of MAD greater than 1 mm (26/29 (90%) vs 118/412 (46%)); p < 0.001), 4 mm (14/29 (48%) vs 49/412 (12%)); p < 0.001), and 6 mm (3/29 (10%) vs 12/412 (3%)); p = 0.03), and a greater MAD extent (4.2 mm, 3.0-5.7 mm vs 2.8 mm, 1.9-4.0 mm; p < 0.001) compared to patients without MVP. MVP was the only morpho-functional abnormality associated with MAD at multivariable analysis (p < 0.001). A high burden of ventricular ectopic beats at baseline Holter-electrocardiogram was associated with MAD ≥4 mm and MAD extent (p < 0.05). The presence of MAD ≥1 mm (0.9% vs 1.8%; p = 0.46), MAD ≥4 mm (1.6% vs 1.3%; p = 0.87), or MVP (3.5% vs 1.2%; p = 0.32) were not associated with the study endpoint, whereas patients with MAD ≥6 mm showed a trend toward a higher likelihood of the study endpoint (6.7% vs 1.2%; p = 0.07).

CONCLUSION

MAD of limited severity was common in consecutive patients undergoing CMR. Patients with MVP showed higher prevalence and greater extent of MAD. Extended MAD was rarer and showed association with ventricular arrhythmias at baseline. The mid-term prognosis of MAD seems benign; however, prospective studies are warranted to search for potential "malignant MAD extents" to improve patients' risk stratification.

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.

Mitral annular disjunction and mitral valve prolapse extrapolating adult data to an adolescent cohort?

PURPOSE OF REVIEW

The aim of this study is to provide an update on mitral valve prolapse (MVP) and mitral annular disjunction (MAD) and who may be at risk for ventricular arrhythmias and sudden cardiac death.

RECENT FINDINGS

MVP is generally considered a benign condition. However, a small subset of patients may be at risk for life-threatening ventricular arrhythmias. Among the risk factors identified in adults include patients with bileaflet mitral valves, myxomatous changes, myocardial fibrosis, and the presence of MAD. Advances in multimodal imaging have allowed for improved identification of fibrosis, anatomical valve derangements, and the amount of MAD. Recent guidelines have suggested that patients with MVP with or without MAD may be at risk for life-threatening arrhythmias if they have had prior ventricular arrhythmias, ventricular dysfunction, or unexplained syncope. Yet, extrapolation of adult data to a pediatric cohort with similar MVP and MAD at this juncture is challenging. There is, however, early evidence that some pediatric patients with significant myocardial fibrosis or abnormal tissue Doppler may be at risk for ventricular tachycardia.

SUMMARY

Mitral valve prolapse and mitral annular disjunction at times coexist and at other times can be seen as isolated entities. While the incidence of arrhythmic MVP is quite rare, there is increasing evidence that certain select adults with MVP may be at risk for ventricular tachycardia and sudden cardiac death. Future multicenter studies are needed to better understand the natural history of arrhythmic mitral valve disease and how early disease manifestation in children may impact findings now being reported in young adults.

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.

The Dutch Idiopathic Ventricular Fibrillation Registry: progress report on the quest to identify the unidentifiable

BACKGROUND

Idiopathic ventricular fibrillation (iVF) is a rare cause of sudden cardiac arrest and, by definition, a diagnosis of exclusion. Due to the rarity of the disease, previous and current studies are limited by their retrospective design and small patient numbers. Even though the incidence of iVF has declined owing to the identification of new disease entities, an important subgroup of patients remains.

AIM

To expand the existing Dutch iVF Registry into a large nationwide cohort of patients initially diagnosed with iVF, to reveal the underlying cause of iVF in these patients, and to improve arrhythmia management.

METHODS

The Dutch iVF Registry includes sudden cardiac arrest survivors with an initial diagnosis of iVF. Clinical data and outcomes are collected. Outcomes include subsequent detection of a diagnosis other than 'idiopathic', arrhythmia recurrence and death. Non-invasive electrocardiographic imaging is used to investigate electropathological substrates and triggers of VF.

RESULTS

To date, 432 patients have been included in the registry (median age at event 40 years (interquartile range 28-52)), 61% male. During a median follow-up of 6 (2-12) years, 38 patients (9%) received a diagnosis other than 'idiopathic'. Eleven iVF patients were characterised with electrocardiographic imaging.

CONCLUSION

The Dutch iVF Registry is currently the largest of its kind worldwide. In this heterogeneous population of index patients, we aim to identify common functional denominators associated with iVF. With the implementation of non-invasive electrocardiographic imaging and other diagnostic modalities (e.g. echocardiographic deformation, cardiac magnetic resonance), we advance the possibilities to reveal pro-fibrillatory substrates.

Mitral annular disjunction in idiopathic ventricular fibrillation patients: just a bystander or a potential cause?

AIMS

Previously, we demonstrated that inferolateral mitral annular disjunction (MAD) is more prevalent in patients with idiopathic ventricular fibrillation (IVF) than in healthy controls. In the present study, we advanced the insights into the prevalence and ventricular arrhythmogenicity by inferolateral MAD in an even larger IVF cohort.

METHODS AND RESULTS

This retrospective multi-centre study included 185 IVF patients [median age 39 (27, 52) years, 40% female]. Cardiac magnetic resonance images were analyzed for mitral valve and annular abnormalities and late gadolinium enhancement. Clinical characteristics were compared between patients with and without MAD. MAD in any of the 4 locations was present in 112 (61%) IVF patients and inferolateral MAD was identified in 24 (13%) IVF patients. Mitral valve prolapse (MVP) was found in 13 (7%) IVF patients. MVP was more prevalent in patients with inferolateral MAD compared with patients without inferolateral MAD (42 vs. 2%, P < 0.001). Pro-arrhythmic characteristics in terms of a high burden of premature ventricular complexes (PVCs) and non-sustained ventricular tachycardia (VT) were more prevalent in patients with inferolateral MAD compared to patients without inferolateral MAD (67 vs. 23%, P < 0.001 and 63 vs. 41%, P = 0.046, respectively). Appropriate implantable cardioverter defibrillator therapy during follow-up was comparable for IVF patients with or without inferolateral MAD (13 vs. 18%, P = 0.579).

CONCLUSION

A high prevalence of inferolateral MAD and MVP is a consistent finding in this large IVF cohort. The presence of inferolateral MAD is associated with a higher PVC burden and non-sustained VTs. Further research is needed to explain this potential interplay.

Mitral annular disjunction in out-of-hospital cardiac arrest patients-a retrospective cardiac MRI study

BACKGROUND

Mitral annular disjunction (MAD), defined as defective attachment of the mitral annulus to the ventricular myocardium, has recently been linked to malignant arrhythmias. However, its role and prognostic significance in patients requiring cardiopulmonary resuscitation (CPR) remain unknown. This retrospective analysis aimed to describe the prevalence and significance of MAD by cardiac magnetic resonance (CMR) imaging in out-of-hospital cardiac arrest (OHCA) patients.

METHODS

Eighty-six patients with OHCA and a CMR scan 5 days after CPR (interquartile range (IQR): 49 days before - 9 days after) were included. MAD was defined as disjunction-extent ≥ 1 mm in CMR long-axis cine-images. Medical records were screened for laboratory parameters, comorbidities, and a history of arrhythmia.

RESULTS

In 34 patients (40%), no underlying cause for OHCA was found during hospitalization despite profound diagnostics. Unknown-cause OHCA patients showed a higher prevalence of MAD compared to definite-cause patients (56% vs. 10%, p < 0.001) and had a MAD-extent of 6.3 mm (IQR: 4.4-10.3); moreover, these patients were significantly younger (43 years vs. 61 years, p < 0.001), more often female (74% vs. 21%, p < 0.001) and had fewer comorbidities (hypertension, hypercholesterolemia, coronary artery disease, all p < 0.005). By logistic regression analysis, the presence of MAD remained significantly associated with OHCA of unknown cause (odds ratio: 8.49, 95% confidence interval: 2.37-30.41, p = 0.001) after adjustment for age, presence of hypertension, and hypercholesterolemia.

CONCLUSIONS

MAD is rather common in OHCA patients without definitive aetiology undergoing CMR. The presence of MAD was independently associated to OHCA without an identifiable trigger. Further research is needed to understand the exact role of MAD in OHCA patients.

Description and prevalence of ventricular mitral annular disjunction: variation of normality or pathological variant?

INTRODUCTION AND OBJECTIVES

The aim of this study was to investigate a new variation of the atrial wall-mitral annulus-ventricular wall junction along the mural mitral leaflet and commissures: the ventricular mitral annular disjunction (v-MAD). This new variant is characterized by spatial displacement of the mitral leaflet hinge line by more than 2mm toward the left ventricle.

METHODS

We examined a cohort of autopsied human hearts (n=224, 21.9% females, 47.9±17.6 years) from patients without known cardiovascular disease to identify the presence of v-MAD.

RESULTS

More than half (57.1%) of the hearts showed no signs of MAD in the mural mitral leaflet or mitral commissures. However, v-MAD was found in 23.6% of cases, located within 20.1% of mural leaflets, 2.2% in superolateral commissures, and 1.3% in inferoseptal commissures. V-MAD was not uniformly distributed along the mitral annulus circumference, with the most frequent site being the P2 scallop (19.6% of hearts). The v-MAD height was significantly greater in mural leaflets than in commissures (4.4 mm±1.2 mm vs 2.1 mm±0.1 mm; P<.001). No specific variations in mitral valve morphology or anthropometrical features of donors were associated with the presence or distribution of v-MADs. Microscopic examinations revealed the overlap of the thin layer of atrial myocardium over ventricular myocardium in areas of v-MAD.

CONCLUSIONS

Our study is the first to present a detailed definition and morphometric description of v-MAD. Further studies should focus on the clinical significance of v-MAD to elucidate whether it represents a benign anatomical variant or a significant clinical anomaly.

Determinants of Ventricular Arrhythmias in Mitral Valve Prolapse

BACKGROUND

Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement [LGE]) may account for arrhythmogenesis.

OBJECTIVES

This study investigated the determinants of VA in patients with MVP without significant regurgitation.

METHODS

This study included 108 patients with MVP (66 female; median age: 48 years) without valve regurgitation. All patients underwent 12-lead electrocardiography, 12-lead 24-hour electrocardiographic Holter monitoring, exercise stress test, and cardiac magnetic resonance. Patients were divided into 2 groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch block pattern.

RESULTS

The 62 patients (57%) with arrhythmic MVP showed: 1) higher MAD (median length: 6.0 vs 3.2 mm; P = 0.017); 2) higher prevalence of curling (79% vs 52%; P = 0.012); and 3) higher prevalence of left ventricular LGE (79% vs 52%; P = 0.012). Mediation analysis showed that curling had both a direct (P = 0.03) and indirect effect mediated by LGE (P = 0.04) on VA, whereas the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morphofunctional alterations, in terms of MAD (7.0 vs 4.6 mm; P = 0.004) and presence and severity of curling (respectively, 91% vs 64%; P = 0.010; and 4 vs 3 mm; P = 0.004), compared to those without severe VA.

CONCLUSIONS

In patients with MVP the occurrence of VA with right bundle branch block morphology is the expression of more severe morphologic, mechanical, and tissue alterations. Curling has both a direct and an indirect effect on VA.

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.

Imaging in patients with cardiovascular implantable electronic devices: part 1-imaging before and during device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

More than 500 000 cardiovascular implantable electronic devices (CIEDs) are implanted in the European Society of Cardiology countries each year. The role of cardiovascular imaging in patients being considered for CIED is distinctly different from imaging in CIED recipients. In the former group, imaging can help identify specific or potentially reversible causes of heart block, the underlying tissue characteristics associated with malignant arrhythmias, and the mechanical consequences of conduction delays and can also aid challenging lead placements. On the other hand, cardiovascular imaging is required in CIED recipients for standard indications and to assess the response to device implantation, to diagnose immediate and delayed complications after implantation, and to guide device optimization. The present clinical consensus statement (Part 1) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients undergoing implantation of conventional pacemakers, cardioverter defibrillators, and resynchronization therapy devices. The document summarizes the existing evidence regarding the use of imaging in patient selection and during the implantation procedure and also underlines gaps in evidence in the field. The role of imaging after CIED implantation is discussed in the second document (Part 2).

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 and Pickelhaube sign in children with mitral valve prolapse: A prospective cohort study

BACKGROUND

Mitral annular disjunction (MAD) and the Pickelhaube sign are identified as risk factors for malignant ventricular arrhythmias (VAs) and sudden cardiac death in adults with mitral valve prolapse (MVP); their prevalence and consequences in children have never been studied.

OBJECTIVES

To determine the proportion of MAD in children with MVP, and its potential link with VAs.

METHODS

A cohort of 49 consecutive children (mean age 12.8±3.0 years; 33 females) with MVP and comprehensive clinical arrhythmia (24-hour monitoring) and Doppler echocardiographic characterization, including pulsed-wave tissue Doppler (PWTD) of the lateral mitral annulus, was identified. The relationship between clinical and echocardiographic data and presence of VAs was studied.

RESULTS

MAD was common (n=25; 51%). Only five patients had significant VAs (Lown grade>2) characterized by polymorphic premature ventricular contractions or couplets. MAD was not associated with VAs on 24-hour Holter monitoring, but an association was found between VAs and spiked high-velocity midsystolic signal>16cm/s on PWTD (Pickelhaube sign) (P=0.004), myxomatous mitral valve (P=0.004) and left ventricular dilatation (P=0.01). T-wave inversion in inferolateral leads on electrocardiogram was more frequent in patients with versus without the Pickelhaube sign (P=0.03). No difference was found between patients with or without MAD regarding sex, history of palpitation, severity of mitral regurgitation, aortic root diameter and incidence of connective tissue disorders. Myocardial fibrosis was detected in two of three patients who underwent a complementary cardiac magnetic resonance examination.

CONCLUSIONS

MAD is common in children with MVP; its presence was not associated with significant VAs on 24-hour Holter monitoring, but the Pickelhaube sign and presence of myxomatous mitral valve may help to detect patients prone to significant VAs. Myocardial fibrosis can be detected by cardiac magnetic resonance in children with significant VAs.

Multidimensional Analysis of the Adult Human Heart in Health and Disease using Hierarchical Phase-Contrast Tomography (HiP-CT)

Cardiovascular diseases (CVDs) are a leading cause of death worldwide. Current clinical imaging modalities provide resolution adequate for diagnosis but are unable to provide detail of structural changes in the heart, across length-scales, necessary for understanding underlying pathophysiology of disease. Hierarchical Phase-Contrast Tomography (HiP-CT), using new (4th) generation synchrotron sources, potentially overcomes this limitation, allowing micron resolution imaging of intact adult organs with unprecedented detail. In this proof of principle study (n=2), we show the utility of HiP-CT to image whole adult human hearts ex-vivo: one 'control' without known cardiac disease and one with multiple known cardiopulmonary pathologies. The resulting multiscale imaging was able to demonstrate exemplars of anatomy in each cardiac segment along with novel findings in the cardiac conduction system, from gross (20 um/voxel) to cellular scale (2.2 um/voxel), non-destructively, thereby bridging the gap between macroscopic and microscopic investigations. We propose that the technique represents a significant step in virtual autopsy methods for studying structural heart disease, facilitating research into abnormalities across scales and age-groups. It opens up possibilities for understanding and treating disease; and provides a cardiac 'blueprint' with potential for in-silico simulation, device design, virtual surgical training, and bioengineered heart in the future.

Lifetime exercise dose and ventricular arrhythmias in patients with mitral valve prolapse

AIMS

Patients with mitral valve prolapse (MVP) have high risk of life-threatening ventricular arrhythmias (VAs). Data on the impact of exercise on arrhythmic risk in these patients are lacking. We explored whether lifetime exercise dose was associated with severe VA and with established risk factors in patients with MVP. Furthermore, we explored the circumstances at the VA event.

METHODS AND RESULTS

In this retrospective cohort study, we included patients with MVP and assessed lifetime exercise dose as metabolic equivalents of task (MET) hours/week. Severe VA was defined as sustained ventricular tachycardia or fibrillation, aborted cardiac arrest, and appropriate shock by a primary preventive implantable cardioverter defibrillator. We included 136 MVP patients (48 years [interquartile range (IQR) 35-59], 61% female), and 17 (13%) had previous severe VA. The lifetime exercise dose did not differ in patients with and without severe VA (17 MET h/week [IQR 9-27] vs. 14 MET h/week [IQR 6-31], P = 0.34). Lifetime exercise dose > 9.6 MET h/week was a borderline significant marker for severe VA (OR 3.38, 95% CI 0.92-12.40, P = 0.07), while not when adjusted for age (OR 2.63, 95% CI 0.66-10.56, P = 0.17). Ventricular arrhythmia events occurred most frequently during wakeful rest (53%), followed by exercise (29%) and sleep (12%).

CONCLUSION

We found no clear association between moderate lifetime exercise dose and severe VA in patients with MVP. We cannot exclude an upper threshold for safe levels of exercise. Further studies are needed to explore exercise and risk of severe VA.

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.

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.

The evolving role of cardiovascular magnetic resonance in the assessment of mitral valve prolapse

Mitral valve prolapse (MVP), characterized by a displacement > 2 mm above the mitral annulus of one or both bileaflets, with or without leaflet thickening, is a common valvular heart disease, with a prevalence of approximately 2% in western countries. Although this population has a generally good overall prognosis, MVP can be associated with mitral regurgitation (MR), left ventricular (LV) remodeling leading to heart failure, ventricular arrhythmia, and, the most devastating complication, sudden cardiac death, especially in myxomatous bileaflet prolapse (Barlow's disease). Among several prognostic factors reported in the literature, LV fibrosis and mitral annular disjunction may act as an arrhythmogenic substrate in this population. Cardiac magnetic resonance (CMR) has emerged as a reliable tool for assessing MVP, MR severity, LV remodeling, and fibrosis. Indeed, CMR is the gold standard imaging modality to assess ventricular volume, function, and wall motion abnormalities; it allows accurate calculation of the regurgitant volume and regurgitant fraction in MR using a combination of LV volumetric measurement and aortic flow quantification, independent of regurgitant jet morphology and valid in cases of multiple valvulopathies. Moreover, CMR is a unique imaging modality that can assess non-invasively focal and diffuse fibrosis using late gadolinium enhancement sequences and, more recently, T1 mapping. This review describes the use of CMR in patients with MVP and its role in identifying patients at high risk of ventricular arrhythmia.

Anatomy of the mitral valve relative to controversies concerning the so-called annular disjunction

It is now accepted that the mitral valve functions on the basis of a complex made up of the annulus, the leaflets, the tendinous cords and the papillary muscles. So as to work properly, these components must combine together in harmonious fashion. Despite the features of the arrangement of each component having been the focus of anatomical investigation for centuries, controversies still exist in their inter-relations and how best to describe them. To a large extent, the ongoing problems reflect the fact that, again for centuries, morphologists when describing the heart have ignored the rule that its components should be described as seen in the body during life. Failure to use attitudinally appropriate descriptions underscores a particular current issue, namely the influence of the so-called disjunction within the atrioventricular junction as a potential substrate for leaflet prolapse or malignant arrhythmias. With these difficulties in mind, we have reviewed how the components of the valvar complex can best be described when comparing direct images with those obtained using three-dimensional techniques now used for clinical imaging. We submit that these show that the skirt of leaflet tissue is best described as having aortic and mural components. When the hinge of the mural leaflet is assessed within the overall atrioventricular junction, the so-called disjunction is ubiquitous, but not always in the same place. We further suggest that its significance will best be determined when clinicians describe its presence using attitudinally appropriate terms.

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.

The Role of Cardiovascular Magnetic Resonance in Patients with Mitral Regurgitation

The 2019 Global Burden of Disease (GBD) study estimated that there were approximately 24.2 million people affected worldwide by degenerative mitral regurgitation (MR), resulting in 34,200 deaths. After aortic stenosis, MR is the most prevalent VHD in Europe and the second-most common VHD to pose indications for surgery in western countries. Current ESC and AHA/ACC guidelines for the management of VHD emphasize the importance of an integrative approach for the assessment of MR severity, which is of paramount importance in dictating the timing for surgery. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are the first-line imaging modalities; however, despite the technological advancement, sometimes, the final diagnosis on the degree of the disease may still be challenging. In the last 20 years, CMR has emerged as a robust technique in the assessment of patients with cardiac disease, and, recently, its role is gaining more and more importance in the field of VHD. In fact, CMR is the gold standard in the assessment of cardiac volumes, and it is possible to accurately evaluate the regurgitant volume. The purpose of this review is to outline the current state-of-the-art management of MR by using Cardiac Magnetic Resonance (CMR).